[Alan Rutlidge]

"Patrick Turner" wrote in message
...


Alan Rutlidge wrote:

"Trevor Wilson" wrote in message
...

"Alan Rutlidge" wrote in message
...

"Trevor Wilson" wrote in message
...

"Alan Rutlidge" wrote in
message
...

So what you are implying is that a transistor tester, capable of
reading current gain and Vbe is beyond the budget or the average
electronics tech and beyond his / her competency to use? Pull the
other one Trevor, it's got bells on it.

**No. That's not what I'm telling you. The problem is acquiring the
sheer number of devices, in order to obtain suitable matches. Not
only
that, but Peter matches his large signal devices at 1 Amp. Few techs
bother testing at more than a few ma.

So what's going to happen if one of my output devices fails and there
are
no matching spares?

**That is a reasonable concern. That *may* happen one day. You may need
to
consider your options at that time. However, right now, there are
plenty
of spares available. At my best guess, those spares will likely be
available for the next 20 years or so. Possibly longer.

I guess the whole lot of the output devices would need to be replaced.

**Yep. That is one possibility.

So
the customer bears the cost of the other undamaged devices and the
labour
cost associated with that?

**Yep.

Show me the economics in that rationalisation.

**All transistors in the amplifier stages are matched to within 1%
for
hFE and Vbe. The resultant number is written on the top of the
output
devices.

**Maybe, maybe not. Batch numbers don't tell you much. Peter matches
the
devices, based on their MEASURED parameters, not what the
manufacturer
may claim.

I wasn't refering to the transistor manufacturer's batch numbers but
the
numbers hand written on the top of the devices (presumably by PS or
one
of his former employees).

**They're not batch numbers. They're numbers which indicate the hFE and
Vbe matching characteristics of the device. The term 'batch numbers' is
always understood by people in the business to mean the batch number
from
the manufacturer. I am sorry for the misunderstanding.

No problems Trevor, no apology required. Perhaps I should have made
myself
clearer in the first instance.

So, IOW, the numbers written on the tops of the MJ15024 devices in any
one
amplifier module should read the same?
Likewise for the MJ15026 devices (except they could bear a different
number
as they are a different device). Right?

Cheers,
Alan

Alan, Trevor is pulling wool right over your eyes; in broad daylight he
is trying to fool you.

He knows you ain't a technical man, and can be fooled.

Actually I have a Diploma in Electronic Engineering, specialising in
telecommunications.
I am a full time lecturer in electronics and telecommunications as well as a
technical writer and courseware developer.
I have 30+ years industry experience.


Fooling ppl is Trevor's game.

On Usenet I'd prefer to play dumb.



There is no information about **EXACTLY** how transistors used in ME
amps are selected for use.

There is no website explaining it all, and no service manual where
matching info and procedures should be fully explained.

There could be some proof in the eating. When I have the time I'll run a
set of full test measurements on one channel in my ME850 Hi-Cap over a range
of power outputs. I'll measure frequency response, THD, IMD and S/N ratio.
I'll then replace one of the output devices with an off the shelf device of
the same type (say MJE150025) and remeasure the performance of the amplifier
under the same test conditions. If they meaure the same then TW is talking
out of his arse. If there is any significant measureable difference then
perhaps there is some credibility to his statement.

Cheers,
Alan



DO NOT BUY ME AMPS BEFORE FULL SERVICE MANUALS BECOME AVAILABLE.

Plenty of spurious claims have been and cointinue to be made about ME
amps.

Don't believe claims without proof.

Patrick Turner.

[Arny Krueger]

"Trevor Wilson" wrote
in message

"roughplanet" wrote in
message
...

"Trevor Wilson"
wrote in message
...

"Patrick Turner" wrote in
message ...

I never read what Trevor says about ME amps or the way
transistors are matched because its all empty sales
talk and utter BS.

Is device matching more important in a power amp that lacks loop feedback?

Unequivocally yes!

**Read the above very carefully. THIS is exactly what I
am talking about. Every tech on the planet claims to
know more about ME amplifiers than Peter Stein does.
They WILL NOT fit critically matched devices, even when
specifically instructed to do so. They will always take
the easy (cheap) way out. As a consequence, the
performance and reliability of the product will suffer.
I know. I've seen the messes that have been created by
second rate techs, who think they know it all.

Sounds like a believable story.

All the schematics in the world will not help, as long
as techs think they know more than Peter does about his
own product.

Well, they think that he is being hypercautious. We've seen people like this
on this thread.

I know, from my own experience, that some high Global
NFB products benefit from the use of matched devices.
In a product with no Global NFB, the importance of
matching becomes far more crucial.

Agreed.

Gawd TW, You have dug yourself a hole so deep that you
will never get out of it now, no matter what.

More mouth than brains!

Why not go away & have a good think about the logic, or
rather, the lack of it in what you have said, and then
come back & TELL THE TRUTH, THE WHOLE TRUTH & ONLY THE
TRUTH to the other members of this group.

If irony killed!

You will gain at least some respect; more than if you
just keep banging away at the same old gong, which is
now badly dented & in need of replacing.

I don't think that Trevor is infallible and have crossed swords with him
many times. But, when Trevor is right like this, Trevor deserves respect,
not the derision of fools.

**Be specific and I will do my best to answer.

Nice come back, Trevor!

[Trevor Wilson[_2_]]

"Patrick Turner" wrote in message
...


Trevor Wilson wrote:

"Patrick Turner" wrote in message
...




************************************************** **
I never read what Trevor says about ME amps or the way transistors are
matched
because its all empty sales talk and utter BS.
************************************************** **

**Read the above very carefully. THIS is exactly what I am talking about.
Every tech on the planet claims to know more about ME amplifiers than
Peter
Stein does. They WILL NOT fit critically matched devices, even when
specifically instructed to do so. They will always take the easy (cheap)
way
out. As a consequence, the performance and reliability of the product
will
suffer. I know. I've seen the messes that have been created by second
rate
techs, who think they know it all.

All the schematics in the world will not help, as long as techs think
they
know more than Peter does about his own product.

I know, from my own experience, that some high Global NFB products
benefit
from the use of matched devices. In a product with no Global NFB, the
importance of matching becomes far more crucial.

Trevor Wilson

WHAT YOU SAY IS UTTER ****ING BS.

**No, it is not.


Most techs do not assume they know more than Peter Stein.

**You do. Most of the ones I've met seem to. They think that they can
replace output devices in one of his amps with unmatched devices.


In desperation because service manuals are not available, they
may fit whatever transitors can be purchased which have as god as or
better ratings
than those chosen by PS.

The claims you make about the importance of accurate hfe matching
between both all
PNP and NPN output or other transistors is a complete load of ********.

**Wrong.


Good transistor amps function perfectly well with wider tolerances than
you say because of the abundance of
local and other NFB.

**"Good" is your term. not mine. I happen to feel that amplifiers which use
lots of Golbal NFB are not "good". They are average.

Trevor Wilson

[Trevor Wilson[_2_]]

"Alan Rutlidge" wrote in message
...

"Patrick Turner" wrote in message
...


Alan Rutlidge wrote:

"Trevor Wilson" wrote in message
...

"Alan Rutlidge" wrote in message
...

"Trevor Wilson" wrote in message
...

"Alan Rutlidge" wrote in
message
...

So what you are implying is that a transistor tester, capable of
reading current gain and Vbe is beyond the budget or the average
electronics tech and beyond his / her competency to use? Pull the
other one Trevor, it's got bells on it.

**No. That's not what I'm telling you. The problem is acquiring the
sheer number of devices, in order to obtain suitable matches. Not
only
that, but Peter matches his large signal devices at 1 Amp. Few techs
bother testing at more than a few ma.

So what's going to happen if one of my output devices fails and there
are
no matching spares?

**That is a reasonable concern. That *may* happen one day. You may
need to
consider your options at that time. However, right now, there are
plenty
of spares available. At my best guess, those spares will likely be
available for the next 20 years or so. Possibly longer.

I guess the whole lot of the output devices would need to be
replaced.

**Yep. That is one possibility.

So
the customer bears the cost of the other undamaged devices and the
labour
cost associated with that?

**Yep.

Show me the economics in that rationalisation.

**All transistors in the amplifier stages are matched to within 1%
for
hFE and Vbe. The resultant number is written on the top of the
output
devices.

**Maybe, maybe not. Batch numbers don't tell you much. Peter matches
the
devices, based on their MEASURED parameters, not what the
manufacturer
may claim.

I wasn't refering to the transistor manufacturer's batch numbers but
the
numbers hand written on the top of the devices (presumably by PS or
one
of his former employees).

**They're not batch numbers. They're numbers which indicate the hFE
and
Vbe matching characteristics of the device. The term 'batch numbers'
is
always understood by people in the business to mean the batch number
from
the manufacturer. I am sorry for the misunderstanding.

No problems Trevor, no apology required. Perhaps I should have made
myself
clearer in the first instance.

So, IOW, the numbers written on the tops of the MJ15024 devices in any
one
amplifier module should read the same?
Likewise for the MJ15026 devices (except they could bear a different
number
as they are a different device). Right?

Cheers,
Alan

Alan, Trevor is pulling wool right over your eyes; in broad daylight he
is trying to fool you.

He knows you ain't a technical man, and can be fooled.

Actually I have a Diploma in Electronic Engineering, specialising in
telecommunications.
I am a full time lecturer in electronics and telecommunications as well as
a technical writer and courseware developer.
I have 30+ years industry experience.

**As you know, I was aware of this.



Fooling ppl is Trevor's game.

On Usenet I'd prefer to play dumb.



There is no information about **EXACTLY** how transistors used in ME
amps are selected for use.

There is no website explaining it all, and no service manual where
matching info and procedures should be fully explained.

There could be some proof in the eating. When I have the time I'll run a
set of full test measurements on one channel in my ME850 Hi-Cap over a
range of power outputs. I'll measure frequency response, THD, IMD and S/N
ratio. I'll then replace one of the output devices with an off the shelf
device of the same type (say MJE150025) and remeasure the performance of
the amplifier under the same test conditions. If they meaure the same
then TW is talking out of his arse. If there is any significant
measureable difference then perhaps there is some credibility to his
statement.

**Given the number of output devices in your ME850, I would imagine that the
performance difference is likely to be minimal. What you need to do, is
follow Patrick's (really stupid) advice and replace all the outputs with
randomly chosen devices. THEN measure the performance. Make certain you
measure THD from 20Hz - 20kHz. S/N won't change. Nor FR. IMD will. Be aware
that you will compromise reliability by doing this! It will tell you all you
need to know about device matching.

There is no loop feedback to ensure that the output stage will operate
correctly, when unmatched devices are used. This is something that valve
amplifier owners have known for many years. Hence the thriving business in
supplying matched output valves. Such things are not required for most
transistor amplifiers. And certainly not required for MOSFET amplifiers, as
the characteristics of the devices ensure that 'current hogging' can not
occur. Which is why I was surprised when you said that Perreaux claimed
matched devices were used in his amplifiers. Hell, Perreaux didn't even use
drain or source resistors.

Just be careful when you do this.

Trevor Wilson

[Trevor Wilson[_2_]]

"Peter Wieck" wrote in message
...
On Apr 26, 10:41 pm, "Trevor Wilson"
**Except that I was specifically referring to replacing ALL the output
devices in an entire amplifier, yes.

OK... and that would be much like matching tubes - you get a pair/quad
that matches within that pair/quad and is overall within tolerance and
Bob's your uncle. That pair/quad need not match any other pair/quad in
any other amp, just within itself.

So, (picking familiar equipment at random) if I need ten (10) matched
output devices for my Citation 16, I would perhaps have to slog
through maybe 30-40 to get them based on my several experiences with
this process.

**Provided you were not after 1% tolerance, yes.

It is quite likely that of the 20-30 left over, I would
get another ten-set match as well. And any number of pairs/quads.
However, I will also state that I have _NEVER_ had such a catastrophic
failure in my own equipment -though I have seen it in other stuff. I
can only imagine what it would take to create one that did not give
otherwise-warning ahead of time. Yes, a great number of people do not
heed those otherwise-warnings, that is true.

**I just pulled out a selection of MJ15003 devices I recently tested. They
were matched by a major manufacturer, for use with their products (They,
too, insist on matched output devices) Here are the results:

Hfe Vbe
24 0.57
35 0.57
40 0.57
37 0.57
79 0.59
82 0.59
36 0.57
91 0.59
30 0.55
73 0.57
80 0.59
69 0.57


**That has not been my experience. I've never seen devices chosen at
random
as closely matched as you state. Not ever.

That is really too bad.

**It is, nevertheless, reality.

Your suppliers must not specify well when they
bulk-purchase and you must not be willing to pay the going prices for
such care.

**Perhaps. Perhaps 2N3055 devices are closer specc'd than superior devices.

Mouser is not the cheapest supplier on earth, but they
answer their phone with a human being - typically one who knows a bit
- and they stand behind what they sell. DigiKey and Newark are very
nearly as good. I could pay less than a US$ for a 2N3055. Typically I
pay around $2.50 or so inclusive of shipping - for that care.


**Shipping to Australia would swamp any monetary disadvantage.

Trevor Wilson

[Trevor Wilson[_2_]]

"bassett" wrote in message
...

"Trevor Wilson" wrote in message
...

"bassett" wrote in message
...

"Trevor Wilson" wrote in message
...
.

**Let me re-state the situation:

* Peter Stein is supporting and servicing products he manufactured. I
am servicing and supporting ME and other products.
* There are others who service and support ME products. Due to the
careful matching of semiconductors in all ME products, servicing the
output stages by anyone other than PS (or his appointed successor/s) is
a real bad idea.
* Supplying schematics to anyone calling themselves a 'tech', in the
case of ME, may be a very bad idea. Techs who are unable to perform
even basic fault-finding, can end up doing far more damage to the
amplifier.
* In the case of most ME models, the output stages are modular in
format. This makes removal and replacement a quick, simple exercise.
Peter Stein (and his appointed successors) can effect service to those
output modules and the modules posted back, safely, inexpensively and
easily. Freighting amplifiers around the nation is not required. All
that is required, is a competent tech.
* I have seen many ME amplifiers which have been worked on by
incompetent techs. The result is not pretty, nor cheap to rectify.
* Poorly serviced ME amplifiers reflect badly on the product's
reputation.

Trevor Wilson

One would have thought or at least hoped that electronics' would have
advanced, improved, or at the very least progressed to a point where a
30 year old design could be called dated, superseded or at the very
last 'outmoded' By modern technology, multi-layered chips, and
modern manufacturing technique's

**I'll let you into a dirty little secret:

* Amplifier topology (BJT) has not altered since 1965.
* MOSFETs and IGBJTs are the only new devices, necessitating new
topologies to enter the market place. MOSFETs suck (sound-wise) and
IGBJTs have never succeeded.
* Even so-called 'digital amplifiers' (aka: Class D) are not new. They
were around several decades ago.

There you go. No amplifier is significantly new, nor innovative. Peter
Stein released his innovative products in 1976. They were and still are,
very different to almost every other product on the market.


At what point do you decide that up-dating, re-fitting, or simply
replacing old components for new ones, is beyond the scope of
transforming something into what you consider expectable or comparable
to a modern day design. and at the very least on a par with what is
available today.

**I'll put a 1976 model ME up against any mass market product available
today.


Or have you also updated your Holden commodore, by removing the
starting handle out the front of the radiator, and while it might have
been an advantage in the late fifties to have such a leg breaker, we
now have modern electronics' making your starting handle obsolete.

**I'd LIKE to update my Commodore to one or more of the following:
* Direct injection Diesel.
* Direct injection petrol.
* Hybrid Diesel/electric engine.
* Side curtain air bags.
* Stability programme.
* Etc.

I can't because GMH don't make the technology able to be retro-fitted,
nor, if it was, economically viable. At least Peter Stein ensures that
his customers can keep their products up to date. Which is more than can
be said of Rotel, Yamaha, Marantz, Onkyo, Krell, etc.


In short we get to the point where a 30 year old design, is simply
that, nothing more nothing less,

**ALL amplifier designs are at least that old.

Of cause supporting something of that age does
have considerable advantages, for one thing, nothing new needs to be
learned, Old relics constantly breakdown, so an income can be assured
in your retirement years.

**I have news for you: Instead of throwing their amps away, ME owners can
simply update them.


Of cause it could also be argued that a modern day design, would
simply not make it in this modern age, and there would simply be no need
to start manufacturing new models as the diminishing market and the
production costs would make anything new completely out of reach, price
wise to Jo Public, unless it was made in China, Korea or Taiwan,
and for that to happen schematic's would need to be supplied to the
factory of choice, with a undertaking that Chinese laws would need to
change to protect the Copyright's of such valuable documents

**That much is correct. The rest is just wrong.

Trevor Wilson

So at what point do we start to up-date the updated. According to you
it'd like a living
superannuation scheme, or scam depending on your perspective

**Re-read what I wrote. All will become clear.

Trevor Wilson

[Patrick Turner]

Trevor Wilson wrote:

"Patrick Turner" wrote in message
...


Trevor Wilson wrote:

"Patrick Turner" wrote in message
...




************************************************** **
I never read what Trevor says about ME amps or the way transistors are
matched
because its all empty sales talk and utter BS.
************************************************** **

**Read the above very carefully. THIS is exactly what I am talking about.
Every tech on the planet claims to know more about ME amplifiers than
Peter
Stein does. They WILL NOT fit critically matched devices, even when
specifically instructed to do so. They will always take the easy (cheap)
way
out. As a consequence, the performance and reliability of the product
will
suffer. I know. I've seen the messes that have been created by second
rate
techs, who think they know it all.

All the schematics in the world will not help, as long as techs think
they
know more than Peter does about his own product.

I know, from my own experience, that some high Global NFB products
benefit
from the use of matched devices. In a product with no Global NFB, the
importance of matching becomes far more crucial.

Trevor Wilson

WHAT YOU SAY IS UTTER ****ING BS.

**No, it is not.


Most techs do not assume they know more than Peter Stein.

**You do. Most of the ones I've met seem to. They think that they can
replace output devices in one of his amps with unmatched devices.


In desperation because service manuals are not available, they
may fit whatever transitors can be purchased which have as god as or
better ratings
than those chosen by PS.

The claims you make about the importance of accurate hfe matching
between both all
PNP and NPN output or other transistors is a complete load of ********.

**Wrong.


Good transistor amps function perfectly well with wider tolerances than
you say because of the abundance of
local and other NFB.

**"Good" is your term. not mine. I happen to feel that amplifiers which use
lots of Golbal NFB are not "good". They are average.

Trevor Wilson

More total BS from Trevor Wilson without the slightest amount of useful
true information.

DON'T EVER BUY ME AMPS.

THERE ARE NO SERVOCE MANUALS AVAILABLE.

THEY ARE EXPENSIVE AND DIFFICULT TO REPAIR.

Patrick Turner.

[Patrick Turner]

Trevor Wilson wrote:

"Alan Rutlidge" wrote in message
...

"Patrick Turner" wrote in message
...


Alan Rutlidge wrote:

"Trevor Wilson" wrote in message
...

"Alan Rutlidge" wrote in message
...

"Trevor Wilson" wrote in message
...

"Alan Rutlidge" wrote in
message
...

So what you are implying is that a transistor tester, capable of
reading current gain and Vbe is beyond the budget or the average
electronics tech and beyond his / her competency to use? Pull the
other one Trevor, it's got bells on it.

**No. That's not what I'm telling you. The problem is acquiring the
sheer number of devices, in order to obtain suitable matches. Not
only
that, but Peter matches his large signal devices at 1 Amp. Few techs
bother testing at more than a few ma.

So what's going to happen if one of my output devices fails and there
are
no matching spares?

**That is a reasonable concern. That *may* happen one day. You may
need to
consider your options at that time. However, right now, there are
plenty
of spares available. At my best guess, those spares will likely be
available for the next 20 years or so. Possibly longer.

I guess the whole lot of the output devices would need to be
replaced.

**Yep. That is one possibility.

So
the customer bears the cost of the other undamaged devices and the
labour
cost associated with that?

**Yep.

Show me the economics in that rationalisation.

**All transistors in the amplifier stages are matched to within 1%
for
hFE and Vbe. The resultant number is written on the top of the
output
devices.

**Maybe, maybe not. Batch numbers don't tell you much. Peter matches
the
devices, based on their MEASURED parameters, not what the
manufacturer
may claim.

I wasn't refering to the transistor manufacturer's batch numbers but
the
numbers hand written on the top of the devices (presumably by PS or
one
of his former employees).

**They're not batch numbers. They're numbers which indicate the hFE
and
Vbe matching characteristics of the device. The term 'batch numbers'
is
always understood by people in the business to mean the batch number
from
the manufacturer. I am sorry for the misunderstanding.

No problems Trevor, no apology required. Perhaps I should have made
myself
clearer in the first instance.

So, IOW, the numbers written on the tops of the MJ15024 devices in any
one
amplifier module should read the same?
Likewise for the MJ15026 devices (except they could bear a different
number
as they are a different device). Right?

Cheers,
Alan

Alan, Trevor is pulling wool right over your eyes; in broad daylight he
is trying to fool you.

He knows you ain't a technical man, and can be fooled.

Actually I have a Diploma in Electronic Engineering, specialising in
telecommunications.
I am a full time lecturer in electronics and telecommunications as well as
a technical writer and courseware developer.
I have 30+ years industry experience.

**As you know, I was aware of this.



Fooling ppl is Trevor's game.

On Usenet I'd prefer to play dumb.



There is no information about **EXACTLY** how transistors used in ME
amps are selected for use.

There is no website explaining it all, and no service manual where
matching info and procedures should be fully explained.

There could be some proof in the eating. When I have the time I'll run a
set of full test measurements on one channel in my ME850 Hi-Cap over a
range of power outputs. I'll measure frequency response, THD, IMD and S/N
ratio. I'll then replace one of the output devices with an off the shelf
device of the same type (say MJE150025) and remeasure the performance of
the amplifier under the same test conditions. If they meaure the same
then TW is talking out of his arse. If there is any significant
measureable difference then perhaps there is some credibility to his
statement.

**Given the number of output devices in your ME850, I would imagine that the
performance difference is likely to be minimal. What you need to do, is
follow Patrick's (really stupid) advice and replace all the outputs with
randomly chosen devices. THEN measure the performance. Make certain you
measure THD from 20Hz - 20kHz. S/N won't change. Nor FR. IMD will. Be aware
that you will compromise reliability by doing this! It will tell you all you
need to know about device matching.


I did not advise ppl to use randomly chosen devices.

TREVOR WILSON TELLS LIES ON NEWS GROUPS EVERY ****ING DAY.

However, if one did use randomly chosen devices, the amp shoulds still
work
satisfactorily.

BUT THERE IS NO SERVICE MANUALS FOR ME PRODUCTS
WITH **ALL** SCHEMATICS AND ADVICE ABOUT DEVICE MATCHING.

TREVOR WILSON IS A SNAKE OIL SALESMAN.

DO NOT DEAL WITH THIS CHARLATAN.

There is no loop feedback to ensure that the output stage will operate
correctly, when unmatched devices are used.

I HAVE SEEN THE SCHEMATIC FOR SOME MODELS OF ME AMPS.

THERE IS LOTS OF LOCAL LOOP FB APPLIED.

CORRECT OPERATION OF THE OUTPUT STAGE DOES NOT DEPEND ON LOCAL
OR GLOBAL NFB OR UPON CLSELY MATCHED DEVICES.

TREVOR WILSON MAKES THE THE MOST ABSURD AND UNTRUE COMMENTS ABOUT
TECHNICAL
OPERATION OF THE AMPS HE SUPPOSEDLY SERVICES.

TREVOR IS AN IGNORANT JERK.

Of course Trevor sprays his terrible lies and BS around without
anyone able to check on its truth.

There is no place on the webs where ME amp schematics are displayed,
and where anyone with half a brain can see what Trevor is talking about,
thus understanding
that he is a complete fool, and 100% bull**** artist.

DO NOT EVER BUY ME AMPS.


This is something that valve
amplifier owners have known for many years. Hence the thriving business in
supplying matched output valves.


Closely matched output valves are only required where there is only ONE
bias voltage adjustment able to be made and where the tubes operate in
mainly class AB
with a small class A PO.

Trevor knows utterly **** all about tube amps.


HI-Fi PP Tube amps happily tolerate tube differences of up to 20%
in transconductance before anything is heard because the first 10 watts
are class A watts and matching does not matter, and only slightly
increases 2H.



Such things are not required for most
transistor amplifiers. And certainly not required for MOSFET amplifiers, as
the characteristics of the devices ensure that 'current hogging' can not
occur.

"Current hogging"??????

Trevor, please explain in technical terms!!!

Or are you just a ****ing idiot who fails totally to understand
anything?





Which is why I was surprised when you said that Perreaux claimed
matched devices were used in his amplifiers. Hell, Perreaux didn't even use
drain or source resistors.

Drain resistors or collector resistors are never used in SS amps to
ensure
even current conduction between multiple parallel devices.
Source or emitter resistors of between 0.1 and 0.5 ohms ARE used to
ensure each unmatched device conducts very nearly equal current.

The base to emitter voltage required for output transistors to work
ranges between
0.5 to 0.75 volts.
This is a small range of voltage, and the most common emitter resistors
are 0.22 ohms.
1 amp I flow gives 0.22V across the 0.22 ohms, and it produces a large
amount
of series current FB voltage, thus regulating the I flow in the output
transistor.

In my 2 x 300W amp with a six pack of mosfets, I have 0.5 ohm source
resistors
at each source to regulate current flow.
There is utterly no need for close matching of output mosfets.

THD 0.005% at 250W, much lower than an ME amp.

NEVER BELIEVE THE UTTER TWADDLE AND LIES ABOUT MOSFETS AND TUBES WHICH
TREVOR WILSON SPRAYS AROUND.



Just be careful when you do this.

JUST BE CAREFUL WHEN YOU READ TREVOR WILSON'S POSTS BECAUSE THEY ARE
MAINLY ALL BULL****.

Patrick Turner.



Trevor Wilson

[Patrick Turner]

Trevor Wilson wrote:

"Peter Wieck" wrote in message
...
On Apr 26, 10:41 pm, "Trevor Wilson"
**Except that I was specifically referring to replacing ALL the output
devices in an entire amplifier, yes.

OK... and that would be much like matching tubes - you get a pair/quad
that matches within that pair/quad and is overall within tolerance and
Bob's your uncle. That pair/quad need not match any other pair/quad in
any other amp, just within itself.

??????

TREVOR WILSON SPEAKS GIBERISH AGAIN.

So, (picking familiar equipment at random) if I need ten (10) matched
output devices for my Citation 16, I would perhaps have to slog
through maybe 30-40 to get them based on my several experiences with
this process.

**Provided you were not after 1% tolerance, yes.

It is quite likely that of the 20-30 left over, I would
get another ten-set match as well. And any number of pairs/quads.
However, I will also state that I have _NEVER_ had such a catastrophic
failure in my own equipment -though I have seen it in other stuff. I
can only imagine what it would take to create one that did not give
otherwise-warning ahead of time. Yes, a great number of people do not
heed those otherwise-warnings, that is true.

IRELEVANT TWADDLE

**I just pulled out a selection of MJ15003 devices I recently tested. They
were matched by a major manufacturer, for use with their products (They,
too, insist on matched output devices) Here are the results:

Hfe Vbe
24 0.57
35 0.57
40 0.57
37 0.57
79 0.59
82 0.59
36 0.57
91 0.59
30 0.55
73 0.57
80 0.59
69 0.57

TREVOR WILSON ATTEMPTS TO FOLL THE WORLD YET AGAIN WITH LIES AND BS.

HE DOES NOT TELL US THE TEST CONDITIONS AND TESTING METHOD USED TO
ESTABLISH THE HFE.

TREVOR WILSON IS A COMPLETE FOOL, CHARLATAN, AND ****ING CLOWN.

NOBODY CAN HAVE A RATIONAL CONVERSATION WITH TREVOR WILSON
BECAUSE AFTER 2 MINUTES IT ALL SWAMPED BY BULL****.



**That has not been my experience. I've never seen devices chosen at
random
as closely matched as you state. Not ever.

That is really too bad.

**It is, nevertheless, reality.

Your suppliers must not specify well when they
bulk-purchase and you must not be willing to pay the going prices for
such care.

**Perhaps. Perhaps 2N3055 devices are closer specc'd than superior devices.

Mouser is not the cheapest supplier on earth, but they
answer their phone with a human being - typically one who knows a bit
- and they stand behind what they sell. DigiKey and Newark are very
nearly as good. I could pay less than a US$ for a 2N3055. Typically I
pay around $2.50 or so inclusive of shipping - for that care.

**Shipping to Australia would swamp any monetary disadvantage.

Trevor Wilson

There is a huge disadvantage for anyone trying to deal with Trevor
Wilson,
a charlartan and snake oil salesman unable to
explain the simplest technical aspects of amplifiers.

DON'T BUY ME AMPS because there are no service manuals.

Patrick Turner.

[Trevor Wilson[_2_]]

"Patrick Turner" wrote in message
...


Trevor Wilson wrote:

"Peter Wieck" wrote in message
...
On Apr 26, 10:41 pm, "Trevor Wilson"
**Except that I was specifically referring to replacing ALL the output
devices in an entire amplifier, yes.

OK... and that would be much like matching tubes - you get a pair/quad
that matches within that pair/quad and is overall within tolerance and
Bob's your uncle. That pair/quad need not match any other pair/quad in
any other amp, just within itself.

??????

TREVOR WILSON SPEAKS GIBERISH AGAIN.

**LOL! You're responding to Peter Weik. I look forward to his response.


So, (picking familiar equipment at random) if I need ten (10) matched
output devices for my Citation 16, I would perhaps have to slog
through maybe 30-40 to get them based on my several experiences with
this process.

**Provided you were not after 1% tolerance, yes.

It is quite likely that of the 20-30 left over, I would
get another ten-set match as well. And any number of pairs/quads.
However, I will also state that I have _NEVER_ had such a catastrophic
failure in my own equipment -though I have seen it in other stuff. I
can only imagine what it would take to create one that did not give
otherwise-warning ahead of time. Yes, a great number of people do not
heed those otherwise-warnings, that is true.

IRELEVANT TWADDLE

**LOL! You're responding to Peter Weik. I look forward to his response.


**I just pulled out a selection of MJ15003 devices I recently tested.
They
were matched by a major manufacturer, for use with their products (They,
too, insist on matched output devices) Here are the results:

Hfe Vbe
24 0.57
35 0.57
40 0.57
37 0.57
79 0.59
82 0.59
36 0.57
91 0.59
30 0.55
73 0.57
80 0.59
69 0.57

TREVOR WILSON ATTEMPTS TO FOLL THE WORLD YET AGAIN WITH LIES AND BS.

**Incorrect. The transistors are here in my workshop. I invite any
interested parties to check my measurements. Even you.


HE DOES NOT TELL US THE TEST CONDITIONS AND TESTING METHOD USED TO
ESTABLISH THE HFE.

**I used my Peak tester. It was done at around 4ma.


TREVOR WILSON IS A COMPLETE FOOL, CHARLATAN, AND ****ING CLOWN.

NOBODY CAN HAVE A RATIONAL CONVERSATION WITH TREVOR WILSON
BECAUSE AFTER 2 MINUTES IT ALL SWAMPED BY BULL****.

**No need to shout, Patrick. Like a petulant child, stamping your feet and
screaming will get you nowhere. If you wish to carry on a logical, rational
discussion, I am always ready. I will not be bullied nor intimidated by your
childish antics. I'm guessing that Peter Wiek will have something to say
about your antics as well.

Trevor Wilson

[Phil Allison]

"Trevor Wilson"


**I just pulled out a selection of MJ15003 devices I recently tested. They
were matched by a major manufacturer, for use with their products (They,
too, insist on matched output devices) Here are the results:

Hfe Vbe
24 0.57
35 0.57
40 0.57
37 0.57
79 0.59
82 0.59
36 0.57
91 0.59
30 0.55
73 0.57
80 0.59
69 0.57


** Hfe is not a single number - it is a variable.

Vbe is not a single number - it is also a variable.

The Hfe of a power transistor like the MJ15003 needs to be done at an
appropriate level of Ic and Vce or it is meaningless - same goes for Vbe
testing.

Testing the Hfe of a MJ15003 with a small signal transistor tester gives
wrong results.

Testing the Vbe of a MJ15003 with a DMM ( in diode check) is quite
pointless.

Electronics Australia published (in May 1988) my design for a " Simple
Tester for Power Transistors " that determines both parameters
simultaneously, at a meaningful voltage and current levels, so such devices
can be matched for parallel operation.

There was no PCB since the wiring needed was quite minimal - Altronics sold
a kit for it for a few years, K2532.




....... Phil

[Peter Wieck]

On Apr 27, 8:10*pm, "Trevor Wilson" I'm guessing that Peter Wiek will
have something to say
about your antics as well.

Actually not. I did not read Patrick's reply quite as you did, but
that is not-hardly relevant to the discusion at hand.

As to shipping to Australia - one ships by weight at flat increments.
International Priority Mail (United States Postal Service) for a two
pound package - enough for a major bunch of transistors - comes to US$
25.25. About enough for a family of 4 to get fat at McDonalds with not
a great deal of change left over. Nor do I believe for one
hummingbird heartbeat that devices purchased in Australia differ in
any significant way from the same devices from the same maker
purchased in the US. So, somehow, it must get down to how your
suppliers specify their purchases such that the makers send you the
wildly disparate crap and the relatively decent stuff here.

Y'all need to broaden your horizons. Y'all need to read back over this
thread and recognize how wildely nonsensical it has become and how
insane your position as-stated really is. With all due respect, all
Mr. Stein needs to do is state that any ME-made devices 'service-by-
others' have voided whatever warranty exists - however here are the
schematics and service manuals for those of you who wish to understand
the product. And please do NOT attempt to tell me that the
intervention of an outside hand would not be instantly apparent.

Hell, this is nothing new here in the US. Most every maker from the
sublime to the ridiculous publishes this sort of information as a
matter of course.

Peter Wieck
Melrose Park, pA

[Patrick Turner]

Alan Rutlidge wrote:

"Patrick Turner" wrote in message
...


Alan Rutlidge wrote:

"Trevor Wilson" wrote in message
...

"Alan Rutlidge" wrote in message
...

"Trevor Wilson" wrote in message
...

"Alan Rutlidge" wrote in
message
...

So what you are implying is that a transistor tester, capable of
reading current gain and Vbe is beyond the budget or the average
electronics tech and beyond his / her competency to use? Pull the
other one Trevor, it's got bells on it.

**No. That's not what I'm telling you. The problem is acquiring the
sheer number of devices, in order to obtain suitable matches. Not
only
that, but Peter matches his large signal devices at 1 Amp. Few techs
bother testing at more than a few ma.

So what's going to happen if one of my output devices fails and there
are
no matching spares?

**That is a reasonable concern. That *may* happen one day. You may need
to
consider your options at that time. However, right now, there are
plenty
of spares available. At my best guess, those spares will likely be
available for the next 20 years or so. Possibly longer.

I guess the whole lot of the output devices would need to be replaced.

**Yep. That is one possibility.

So
the customer bears the cost of the other undamaged devices and the
labour
cost associated with that?

**Yep.

Show me the economics in that rationalisation.

**All transistors in the amplifier stages are matched to within 1%
for
hFE and Vbe. The resultant number is written on the top of the
output
devices.

**Maybe, maybe not. Batch numbers don't tell you much. Peter matches
the
devices, based on their MEASURED parameters, not what the
manufacturer
may claim.

I wasn't refering to the transistor manufacturer's batch numbers but
the
numbers hand written on the top of the devices (presumably by PS or
one
of his former employees).

**They're not batch numbers. They're numbers which indicate the hFE and
Vbe matching characteristics of the device. The term 'batch numbers' is
always understood by people in the business to mean the batch number
from
the manufacturer. I am sorry for the misunderstanding.

No problems Trevor, no apology required. Perhaps I should have made
myself
clearer in the first instance.

So, IOW, the numbers written on the tops of the MJ15024 devices in any
one
amplifier module should read the same?
Likewise for the MJ15026 devices (except they could bear a different
number
as they are a different device). Right?

Cheers,
Alan

Alan, Trevor is pulling wool right over your eyes; in broad daylight he
is trying to fool you.

He knows you ain't a technical man, and can be fooled.

Actually I have a Diploma in Electronic Engineering, specialising in
telecommunications.
I am a full time lecturer in electronics and telecommunications as well as a
technical writer and courseware developer.
I have 30+ years industry experience.


But how much experience have you had designing and building solid state
amplifiers?

Is it less than Trevor Wilson's experience?

He has NO experience.

He fixes things he hardly understands.

Its nothing to be ashamed of. None of us know everything.
Unless one blathers on to look like one does know a lot, but doesn't.

Someone medically trained and specialising in proctology
may not know very much about brain surgery.



Fooling ppl is Trevor's game.

On Usenet I'd prefer to play dumb.

I'd sure prefer Trevor just shut the **** up.

He makes a true idiot of himself every time he dabbles in techno talk.




There is no information about **EXACTLY** how transistors used in ME
amps are selected for use.

There is no website explaining it all, and no service manual where
matching info and procedures should be fully explained.

There could be some proof in the eating. When I have the time I'll run a
set of full test measurements on one channel in my ME850 Hi-Cap over a range
of power outputs. I'll measure frequency response, THD, IMD and S/N ratio.
I'll then replace one of the output devices with an off the shelf device of
the same type (say MJE150025) and remeasure the performance of the amplifier
under the same test conditions. If they meaure the same then TW is talking
out of his arse. If there is any significant measureable difference then
perhaps there is some credibility to his statement.


With all due respect Alan, you'd be wasting all your time doing such an
experiment.

The F response, THD/IMD and S/N ration and power will remain virtually
unchanged
providing the amp is biased correctly.

In a Cambridge SS 4040 amp I once repaired, I could change the bias from
class C to heavy class A and
there was ZERO sound change.
But the NFB applied in the Cambridge was able to counter the
gross distortions of the open loop condition caused with class C
operation.
The cambridge had a fairly standard Lin type of generic SS circuit but
with an added
j-fet in the gain VAS stage which made the stability too marginal and
led to
mains fuses blowing probably through cross crossconduction at HF when a
shorted speaker
was used.
I removed the j-fet and altered the circuit to a sensible and simpler
design.
Measured THD remained well below audibility.

Now to fully understand what i just said means someone needs to know a
heck of a lot about
amplifiers.

Almost nobody except myself wants to discuss technical matters in groups
because
virtually nobody understands me or understands amplifiers well.
Trevor sure doesn't.
Phil Allison does though, maybe a couple of others, and that's all.


A change from 0.001% THD at 1 watt from a typical SS amp biased into
class A
to say 0.01%, a tenfold increase, cannot be heard at all.

Trevor Wilson only discusses what he wants to and allows me to drag him
around
in the pool of his own **** because it gives ME amps some publicity
which he thinks might increase the sales. Trevor comes equipped
with a pathological desire to be treated like ****.

The part of his brain which limits bull**** outgoings is quite defunct.

He is a very irrational man with extremely shallow knowledge about how
amplifiers work.

He irrationally believes servicing of ME products can only be done by
himself or Stein,
but its because he wishes to maintain the monopoly;
his whole stance is about the money, and the truth doesn't have a chance
under such
conditions.

I am well qualified to pop Trevor Wilson's balloon of bull****.

I operate a fully transparent and open honest repair and handcrafting
amplifier business where all details of what i think are online and
available to all for free.

I expect Wilson and Stein to operate similarly before I can respect
their enterprize
which to me looks shambolic, and devoid of ethics.

The ME range of amplfiers are nice looking and substantially made,
but no better sounding or more reliable than many other brands.
When they fail, the repairs are very difficult to achieve,
and expensive compared to many other brands.

I do not wish to deal with Trevor Wilson because of his bull**** stream
in the Internet.

I would be happy to buy matched transistors or a manual from Stein if
they were
available at the right prices.

I wish Trevor Wilson would just shut the **** up because
everything he says is meaningless and uninformative crap.

He brings the ME brand into disrepute.

Of course, there

SHOULD BE MANUALS FOR ALL ME MODELS.

I SURE HOPE THAT WHEN PPL DIAL IN ME AMPLIFIERS UNDER GOOGLE
ALL MY NEGATIVE POSTS WILL COME UP.

To change the situation, Peter Stein should produce manuals
for sale, and give all schematics and explanations and
include the simple methods of matching the transistors.

People wanting to own an ME 850 amp should get a far better deal
than they get now for their $6,000.

There MUST be a full service manual.

DO NOT BUY ME AMPS BEFORE FULL SERVICE MANUALS BECOME AVAILABLE.

Patrick Turner.











Cheers,
Alan


DO NOT BUY ME AMPS BEFORE FULL SERVICE MANUALS BECOME AVAILABLE.

Plenty of spurious claims have been and cointinue to be made about ME
amps.

Don't believe claims without proof.

Patrick Turner.

[Trevor Wilson[_2_]]

"Patrick Turner" wrote in message
...


Trevor Wilson wrote:

"Alan Rutlidge" wrote in message
...

"Patrick Turner" wrote in message
...


Alan Rutlidge wrote:

"Trevor Wilson" wrote in message
...

"Alan Rutlidge" wrote in
message
...

"Trevor Wilson" wrote in
message
...

"Alan Rutlidge" wrote in
message
...

So what you are implying is that a transistor tester, capable of
reading current gain and Vbe is beyond the budget or the average
electronics tech and beyond his / her competency to use? Pull
the
other one Trevor, it's got bells on it.

**No. That's not what I'm telling you. The problem is acquiring
the
sheer number of devices, in order to obtain suitable matches. Not
only
that, but Peter matches his large signal devices at 1 Amp. Few
techs
bother testing at more than a few ma.

So what's going to happen if one of my output devices fails and
there
are
no matching spares?

**That is a reasonable concern. That *may* happen one day. You may
need to
consider your options at that time. However, right now, there are
plenty
of spares available. At my best guess, those spares will likely be
available for the next 20 years or so. Possibly longer.

I guess the whole lot of the output devices would need to be
replaced.

**Yep. That is one possibility.

So
the customer bears the cost of the other undamaged devices and the
labour
cost associated with that?

**Yep.

Show me the economics in that rationalisation.

**All transistors in the amplifier stages are matched to within
1%
for
hFE and Vbe. The resultant number is written on the top of the
output
devices.

**Maybe, maybe not. Batch numbers don't tell you much. Peter
matches
the
devices, based on their MEASURED parameters, not what the
manufacturer
may claim.

I wasn't refering to the transistor manufacturer's batch numbers
but
the
numbers hand written on the top of the devices (presumably by PS
or
one
of his former employees).

**They're not batch numbers. They're numbers which indicate the hFE
and
Vbe matching characteristics of the device. The term 'batch
numbers'
is
always understood by people in the business to mean the batch
number
from
the manufacturer. I am sorry for the misunderstanding.

No problems Trevor, no apology required. Perhaps I should have made
myself
clearer in the first instance.

So, IOW, the numbers written on the tops of the MJ15024 devices in
any
one
amplifier module should read the same?
Likewise for the MJ15026 devices (except they could bear a different
number
as they are a different device). Right?

Cheers,
Alan

Alan, Trevor is pulling wool right over your eyes; in broad daylight
he
is trying to fool you.

He knows you ain't a technical man, and can be fooled.

Actually I have a Diploma in Electronic Engineering, specialising in
telecommunications.
I am a full time lecturer in electronics and telecommunications as well
as
a technical writer and courseware developer.
I have 30+ years industry experience.

**As you know, I was aware of this.



Fooling ppl is Trevor's game.

On Usenet I'd prefer to play dumb.



There is no information about **EXACTLY** how transistors used in ME
amps are selected for use.

There is no website explaining it all, and no service manual where
matching info and procedures should be fully explained.

There could be some proof in the eating. When I have the time I'll run
a
set of full test measurements on one channel in my ME850 Hi-Cap over a
range of power outputs. I'll measure frequency response, THD, IMD and
S/N
ratio. I'll then replace one of the output devices with an off the
shelf
device of the same type (say MJE150025) and remeasure the performance
of
the amplifier under the same test conditions. If they meaure the same
then TW is talking out of his arse. If there is any significant
measureable difference then perhaps there is some credibility to his
statement.

**Given the number of output devices in your ME850, I would imagine that
the
performance difference is likely to be minimal. What you need to do, is
follow Patrick's (really stupid) advice and replace all the outputs with
randomly chosen devices. THEN measure the performance. Make certain you
measure THD from 20Hz - 20kHz. S/N won't change. Nor FR. IMD will. Be
aware
that you will compromise reliability by doing this! It will tell you all
you
need to know about device matching.


I did not advise ppl to use randomly chosen devices.

**Yes, you do. Here are your words:

*********************************************
I never read what Trevor says about ME amps or the way transistors are
matched because its all empty sales talk and utter BS.
*********************************************

I am here to tell you that you are wrong.


TREVOR WILSON TELLS LIES ON NEWS GROUPS EVERY ****ING DAY.

However, if one did use randomly chosen devices, the amp shoulds still
work
satisfactorily.

**Here is exactly what I am talking about. You feel that you know more about
the amplifiers than the designer does.


BUT THERE IS NO SERVICE MANUALS FOR ME PRODUCTS
WITH **ALL** SCHEMATICS AND ADVICE ABOUT DEVICE MATCHING.

TREVOR WILSON IS A SNAKE OIL SALESMAN.

DO NOT DEAL WITH THIS CHARLATAN.

There is no loop feedback to ensure that the output stage will operate
correctly, when unmatched devices are used.

I HAVE SEEN THE SCHEMATIC FOR SOME MODELS OF ME AMPS.

THERE IS LOTS OF LOCAL LOOP FB APPLIED.

CORRECT OPERATION OF THE OUTPUT STAGE DOES NOT DEPEND ON LOCAL
OR GLOBAL NFB OR UPON CLSELY MATCHED DEVICES.

TREVOR WILSON MAKES THE THE MOST ABSURD AND UNTRUE COMMENTS ABOUT
TECHNICAL
OPERATION OF THE AMPS HE SUPPOSEDLY SERVICES.

TREVOR IS AN IGNORANT JERK.

Of course Trevor sprays his terrible lies and BS around without
anyone able to check on its truth.

There is no place on the webs where ME amp schematics are displayed,
and where anyone with half a brain can see what Trevor is talking about,
thus understanding
that he is a complete fool, and 100% bull**** artist.

DO NOT EVER BUY ME AMPS.


This is something that valve
amplifier owners have known for many years. Hence the thriving business
in
supplying matched output valves.


Closely matched output valves are only required where there is only ONE
bias voltage adjustment able to be made and where the tubes operate in
mainly class AB
with a small class A PO.

Trevor knows utterly **** all about tube amps.


HI-Fi PP Tube amps happily tolerate tube differences of up to 20%
in transconductance before anything is heard because the first 10 watts
are class A watts and matching does not matter, and only slightly
increases 2H.



Such things are not required for most
transistor amplifiers. And certainly not required for MOSFET amplifiers,
as
the characteristics of the devices ensure that 'current hogging' can not
occur.

"Current hogging"??????

**Certainly. I am always happy to assist with your education:

http://en.wikipedia.org/wiki/Thermal_runaway

http://www.siliconfareast.com/rtl.htm

http://www.altavistaaudio.com/MosfetMatching.html

When BJTs are connected in parallel, the higher gain devices will tend to
'hog' bias current. Under extreme conditions, this can lead to thermal
runaway. Such problems are rare in MOSFET amps. MOSFETs negative tempco of
gm makes them more resistant to this effect.


Trevor, please explain in technical terms!!!

Or are you just a ****ing idiot who fails totally to understand
anything?

**Wait for the explanation, before stomping your feet and screaming.






Which is why I was surprised when you said that Perreaux claimed
matched devices were used in his amplifiers. Hell, Perreaux didn't even
use
drain or source resistors.

Drain resistors or collector resistors are never used in SS amps to
ensure
even current conduction between multiple parallel devices.
Source or emitter resistors of between 0.1 and 0.5 ohms ARE used to
ensure each unmatched device conducts very nearly equal current.

**Not in Perreaux amps, they weren't. Perreaux amps used no source or drain
resistors. The new models may well do so, but the old ones certainly did
not. And, just to remind you: It is Perreaux amps that I am SPECIFICALLY
speaking about, as that is the topic Alan brought up.


The base to emitter voltage required for output transistors to work
ranges between
0.5 to 0.75 volts.
This is a small range of voltage, and the most common emitter resistors
are 0.22 ohms.
1 amp I flow gives 0.22V across the 0.22 ohms, and it produces a large
amount
of series current FB voltage, thus regulating the I flow in the output
transistor.

In my 2 x 300W amp with a six pack of mosfets, I have 0.5 ohm source
resistors
at each source to regulate current flow.
There is utterly no need for close matching of output mosfets.

**Of course. MOSFETs are inherently protected.


THD 0.005% at 250W, much lower than an ME amp.

**Indeed.


NEVER BELIEVE THE UTTER TWADDLE AND LIES ABOUT MOSFETS AND TUBES WHICH
TREVOR WILSON SPRAYS AROUND.



Just be careful when you do this.

JUST BE CAREFUL WHEN YOU READ TREVOR WILSON'S POSTS BECAUSE THEY ARE
MAINLY ALL BULL****.

**Screaming and stomping your feet won't help you convey your message.

Trevor Wilson



** Posted from http://www.teranews.com **

[Patrick Turner]

Trevor Wilson wrote:

"Patrick Turner" wrote in message
...


Trevor Wilson wrote:

"Peter Wieck" wrote in message
...
On Apr 26, 10:41 pm, "Trevor Wilson"
**Except that I was specifically referring to replacing ALL the output
devices in an entire amplifier, yes.

OK... and that would be much like matching tubes - you get a pair/quad
that matches within that pair/quad and is overall within tolerance and
Bob's your uncle. That pair/quad need not match any other pair/quad in
any other amp, just within itself.

??????

TREVOR WILSON SPEAKS GIBERISH AGAIN.

**LOL! You're responding to Peter Weik. I look forward to his response.


So, (picking familiar equipment at random) if I need ten (10) matched
output devices for my Citation 16, I would perhaps have to slog
through maybe 30-40 to get them based on my several experiences with
this process.

**Provided you were not after 1% tolerance, yes.

It is quite likely that of the 20-30 left over, I would
get another ten-set match as well. And any number of pairs/quads.
However, I will also state that I have _NEVER_ had such a catastrophic
failure in my own equipment -though I have seen it in other stuff. I
can only imagine what it would take to create one that did not give
otherwise-warning ahead of time. Yes, a great number of people do not
heed those otherwise-warnings, that is true.

IRELEVANT TWADDLE

**LOL! You're responding to Peter Weik. I look forward to his response.


**I just pulled out a selection of MJ15003 devices I recently tested.
They
were matched by a major manufacturer, for use with their products (They,
too, insist on matched output devices) Here are the results:

Hfe Vbe
24 0.57
35 0.57
40 0.57
37 0.57
79 0.59
82 0.59
36 0.57
91 0.59
30 0.55
73 0.57
80 0.59
69 0.57

TREVOR WILSON ATTEMPTS TO FOLL THE WORLD YET AGAIN WITH LIES AND BS.

**Incorrect. The transistors are here in my workshop. I invite any
interested parties to check my measurements. Even you.


HE DOES NOT TELL US THE TEST CONDITIONS AND TESTING METHOD USED TO
ESTABLISH THE HFE.

**I used my Peak tester. It was done at around 4ma.


TREVOR WILSON IS A COMPLETE FOOL, CHARLATAN, AND ****ING CLOWN.

NOBODY CAN HAVE A RATIONAL CONVERSATION WITH TREVOR WILSON
BECAUSE AFTER 2 MINUTES IT ALL SWAMPED BY BULL****.

**No need to shout, Patrick. Like a petulant child, stamping your feet and
screaming will get you nowhere. If you wish to carry on a logical, rational
discussion, I am always ready. I will not be bullied nor intimidated by your
childish antics. I'm guessing that Peter Wiek will have something to say
about your antics as well.

Trevor Wilson

Trevor, everything you say is BS and irrational, far worse than
shouting.

So, shut the **** up.

I am not shouting. Just stating the obvious to anyone with 1/2 a brain.

YOU BELIEVE IN POOR BUSINESS ETHICS AND POOR BUSINESS STANDARDS,
and you suppot the idea that there does not need to be
any service manuals for ME amplifiers.

Wot a **** you are!!

If you want respect, then you must earn it.

Since you never respect anyone else, you have a difficult life ahead.

Patrick Turner.

[Patrick Turner]

Peter Wieck wrote:

On Apr 27, 8:10 pm, "Trevor Wilson" I'm guessing that Peter Wiek will
have something to say
about your antics as well.

Actually not. I did not read Patrick's reply quite as you did, but
that is not-hardly relevant to the discusion at hand.

As to shipping to Australia - one ships by weight at flat increments.
International Priority Mail (United States Postal Service) for a two
pound package - enough for a major bunch of transistors - comes to US$
25.25. About enough for a family of 4 to get fat at McDonalds with not
a great deal of change left over. Nor do I believe for one
hummingbird heartbeat that devices purchased in Australia differ in
any significant way from the same devices from the same maker
purchased in the US. So, somehow, it must get down to how your
suppliers specify their purchases such that the makers send you the
wildly disparate crap and the relatively decent stuff here.

Y'all need to broaden your horizons. Y'all need to read back over this
thread and recognize how wildely nonsensical it has become and how
insane your position as-stated really is. With all due respect, all
Mr. Stein needs to do is state that any ME-made devices 'service-by-
others' have voided whatever warranty exists - however here are the
schematics and service manuals for those of you who wish to understand
the product. And please do NOT attempt to tell me that the
intervention of an outside hand would not be instantly apparent.

Hell, this is nothing new here in the US. Most every maker from the
sublime to the ridiculous publishes this sort of information as a
matter of course.

Peter Wieck
Melrose Park, pA

Peter Stein has sought to deprive service people of the vital
information to enable ME amp repairs easily and cheaply.


Only one guy, a jerk Trevor Wilson repairs ME amps in Sydney who I am
aware of.
I know of no other techs in Oz for ME.

There are no available schematics or manuals available and with all
explanatory notes
including exactly how to match transistors where deemed necessary.

Stein lives in far North Queensland and having a heavy amp sent up there
and back
from southern states is a huge cost and breakages during such trips are
common.
People tend to not pack their amps well enough, and the transport ppl
tend to drop
things, or allow other things in the trucks to crash around on-route.

There are plenty of capable techs able to repair ME amps satisfactorily
like any other brand if they were able to buy the manual or buy the
required transistors
to maintain the design integrity.

Sadly, Stein AND Wilson do not wish to do a single damn thing about the
appallingly bad arrangement for ME amp service.

Its due to the appalling after sales support and service situation that
I recommend nobody buy any ME products until the service situation
improves.

Patrick Turner.

[Trevor Wilson[_2_]]

"Peter Wieck" wrote in message
...
On Apr 27, 8:10 pm, "Trevor Wilson" I'm guessing that Peter Wiek will
have something to say
about your antics as well.

Actually not. I did not read Patrick's reply quite as you did, but
that is not-hardly relevant to the discusion at hand.

**Here are his words, which were directed at you:

"TREVOR WILSON SPEAKS GIBERISH AGAIN."

Since Patrick was responding to YOUR words, he, therefore claimed that you
spoke gibberish.

Here is something else he said (in response to YOUR words):

"IRELEVANT TWADDLE"

Clearly, Patrick feels that you speak "irelevant twaddle".


As to shipping to Australia - one ships by weight at flat increments.
International Priority Mail (United States Postal Service) for a two
pound package - enough for a major bunch of transistors - comes to US$
25.25. About enough for a family of 4 to get fat at McDonalds with not
a great deal of change left over. Nor do I believe for one
hummingbird heartbeat that devices purchased in Australia differ in
any significant way from the same devices from the same maker
purchased in the US. So, somehow, it must get down to how your
suppliers specify their purchases such that the makers send you the
wildly disparate crap and the relatively decent stuff here.

**I provided a list of devices supplied by a Canadian manufacturer and the
Hfe figures. They are far from closely matched.


Y'all need to broaden your horizons. Y'all need to read back over this
thread and recognize how wildely nonsensical it has become and how
insane your position as-stated really is.

**Which position is that? Please be precise in your answer and refer to MY
position, not what Patrick claims is my position.

With all due respect, all
Mr. Stein needs to do is state that any ME-made devices 'service-by-
others' have voided whatever warranty exists

**That is a given.

- however here are the
schematics and service manuals for those of you who wish to understand
the product. And please do NOT attempt to tell me that the
intervention of an outside hand would not be instantly apparent.

**Why should Mr Stein provide service data for all and sundry? Peter
presently provides a fast, effective method of service for all products
manufactured by his company since 1976.


Hell, this is nothing new here in the US. Most every maker from the
sublime to the ridiculous publishes this sort of information as a
matter of course.


**Some do, some don't. Manufacturers are entitled to protect their
intellectual property in any way they see fit. They are also entitled to
protect the reputation of their product from people like Patrick, who feel
that fitting matched output devices is unnecessary.

Trevor Wilson

[keithr]

Hey girls, how about you put away the handbags and stop spitting at each
other. Lets put it this way, if you really feel that, for some reason, you
need to blow 6 grand on an amp and you like the noise that the ME makes, go
ahead, just don't expect Patrick to fix it. Personally, I can think of much
better uses for that amount of money, after all it seems to be generally
agreed that most listening is done at quite modest levels and there are much
more reasonable options that will give virtually identical results at those
sorts of levels. I suspect that the psycho-acoustic effect comes into play
at this sort of level, after all if it doesn't sound any better than
something bought for a grand or less you are going to feel pretty dumb, so
it is going to sound better isn't it?

"Patrick Turner" wrote in message
...

Almost nobody except myself wants to discuss technical matters in groups
because
virtually nobody understands me

It must be very lonely being that clever Patrick

or understands amplifiers well.

Plenty of us understand amplifiers, on the scale of complexity of things
electronic they don't rate very far up the tree, there is a lot more hocus
pocus there than scientific method. Many people don't get involved in
technical discussions either because they don't have the time to write huge
tomes, or because these discussions usually end up in a **** fight

Trevor sure doesn't.
Phil Allison does though, maybe a couple of others, and that's all.

Like I said **** fights (and abuse)

To change the situation, Peter Stein should produce manuals
for sale, and give all schematics and explanations and
include the simple methods of matching the transistors.

There certainly should be a manual available at a reasonable price, but this
is one of the problems with boutique manufacturers, they can't usually
afford a technical writer to do the job, and the last person that you want
doing it is the designer.

include the simple methods of matching the transistors.

Far better to design curcuits that do not require component matching to
within 1%

People wanting to own an ME 850 amp should get a far better deal
than they get now for their $6,000.

Yes like $4000 change.

Keith

[keithr]

"Patrick Turner" wrote in message
...

Hardly anyone here except Phil Allison or myself have any technical
training or experience.

What technical training Patrick? In your own words:-

"In about 1993 my career as a licensed building construction contractor was
coming to a close because my knees began to fail to keep up with the
creativity with bricks, concrete, lumber, and climbing up ladders.
At that time I had become very interested in my hobby of electronics while
trying to improve my own sound system. It consisted of a cheap solid state
receiver and speakers I'd built in 1977 and all designed mainly by
guesswork. During some particularly arduous work on a roof my knees went on
strike for 9 months, and I could not work hard at all. So I sought to train
myself in some alternative method of earning a living so for a couple of
years I learnt all I could about vacuum tube amps and speakers, so I could
try to earn a living from what was a hobby."

Doesn't exactly found like a formal education in electronics to me, I think
that a number of people here have more training and experience than that.

Keith

[Patrick Turner]

keithr wrote:

snip irelevants,

To change the situation, Peter Stein should produce manuals
for sale, and give all schematics and explanations and
include the simple methods of matching the transistors.

There certainly should be a manual available at a reasonable price, but this
is one of the problems with boutique manufacturers, they can't usually
afford a technical writer to do the job, and the last person that you want
doing it is the designer.

Wrong.

Peter Stein has once appeared on the news groups to slow up the bull****
stream from Trevor
Wilson. Its was not a happy episode.

Stein has no trouble typing plain english, and would, like myself, have
no trouble
whatsover drafting up a comprehensive manual.

He would do it better than an employed writer who would, without Peter's
knowledge, make a cock up of the manual.

I didn't need some dumb & expensive writer **** to write my website and
draw up all the schematics.

If you cannot and or will not write up your own
true story about your productions then something is very wrong.


include the simple methods of matching the transistors.

Far better to design curcuits that do not require component matching to
within 1%

People wanting to own an ME 850 amp should get a far better deal
than they get now for their $6,000.

Yes like $4000 change.

Peter Stein doesn't care that his product appeals to only a tiny itzt
bitzy
weeny percentage of ppl.

He must think he can "hang out" for the big price.

However, I could also be accused of charging too much per watt.

But the work I do for $6,000 is vastly more than whatever Peter Stein
does.

Any SS amp is child's play to make compared to a serious tube amp.

Then it depends who you compare me to. Some chinese makers are selling
5050 Watt stereo tube4 amps on-line
and direct from the maker without western round eye arsole middlemen for
$700.

But they are junk, and badly made.

The Real Mccoy is much more expensive.

I don't care if you make steam engines forsale. Good luck if you do.

But if you didn't have the service information about your engines, i'd
be right onto you.


My overwhelming concern in this thread is that
Peter Stein and that idiot fool Trevor Wilson fail to see that its
necessary to have all constructional information and schematics of their
products
either available online for free or available as a hard copy workshop
service manual for a fee.

Trevor accuses me of SHOUTING but he spews mountains of utter lies,
bull****,
and nothing really informative at all.

He has never designed or built an amp in his life,
but poses as a know all.

Patrick Turner.





Keith

[keithr]

"Trevor Wilson" wrote in message
...

Good transistor amps function perfectly well with wider tolerances than
you say because of the abundance of
local and other NFB.

**"Good" is your term. not mine. I happen to feel that amplifiers which
use lots of Golbal NFB are not "good". They are average.

Trevor Wilson

Speaking as one who has never seen, heard, or even smelled an ME amp perhaps
you can clear something up for me. As I understand it the ME is made up of
several modules in the signal path. Each of these modules has it's own
feedback loop. Assuming that the module and it's feedback path are correctly
designed and thus pass an undistorted signal to the next downstream module,
why does this require such tight tolerancing in the output stage? I do
assume that the ouput stage module has it's own feedback loop and is being
fed an undistorted signal. After all, even with global feedback, I know of
no design that takes the feedback loop back to the input of the pre-amp so
it is not entirely global even in that case.

Keith

[Patrick Turner]

keithr wrote:

"Patrick Turner" wrote in message
...

Hardly anyone here except Phil Allison or myself have any technical
training or experience.

What technical training Patrick? In your own words:-

"In about 1993 my career as a licensed building construction contractor was
coming to a close because my knees began to fail to keep up with the
creativity with bricks, concrete, lumber, and climbing up ladders.
At that time I had become very interested in my hobby of electronics while
trying to improve my own sound system. It consisted of a cheap solid state
receiver and speakers I'd built in 1977 and all designed mainly by
guesswork. During some particularly arduous work on a roof my knees went on
strike for 9 months, and I could not work hard at all. So I sought to train
myself in some alternative method of earning a living so for a couple of
years I learnt all I could about vacuum tube amps and speakers, so I could
try to earn a living from what was a hobby."

Doesn't exactly found like a formal education in electronics to me, I think
that a number of people here have more training and experience than that.

Keith

Keith, I served my apprenticeship as an amp designer.
Because there wasn't a course at any tech or uni where a degree or
certificate in Triodology
is available, I proceded to qualify myself independantly and privately.

One soon learns to swim after throwing oneself into the deep end.

Much of what i learnt as a construction designer builder was learnt from
vast onsite experience,
and was not just out of a book. I did however become a qualified
carpeter-joiner as a young man and
went on to study at night to get a Building Certificate. Most of what I
knew and used daily
was on the job experience.

I have never claimed to have been formerly educated in electronics at
some institution of learning.

I became entirely self taught BEFORE I even got a PC or learnt to type
in 2000.

This doesn't mean I ain't well educated about all the issues surrounding
audio amplifiers.

If I had to switch to say radio telescope electronics, i'd be lost until
I learned all about
it all. Takes time.
I believe I could do that if I tried.

A lady of 95 here just got her Master's Degree in Anthropology.

Its remarkable what some folks are able to do.

One guy here I know well became a world expert on hang-glider
aeronautics.
He lived to try out his ideas.
No formal education though.

My website now atracts an average of 450 hits daily, mainly from diyer's
wanting to learn,
and because I have tried to make it easy, simple, and well explained
without contradiction.

Its NOT rocket science, or like brain surgery.


Since 2000, there has never been any valid criticism of my site by
anyone except
for the inevitable typing mistake, or minor math mistake which I have
fixed after being informed.

Meanwhile, where are Trevor Wilson's or Peter Steins' highly informative
websites?

They like big noting themselves, and asking the high prices,
but they don't even have workshop manuals, which is the epitome of
poor ethics.

Patrick Turner.

[Trevor Wilson[_2_]]

"keithr" wrote in message
...

"Trevor Wilson" wrote in message
...

Good transistor amps function perfectly well with wider tolerances than
you say because of the abundance of
local and other NFB.

**"Good" is your term. not mine. I happen to feel that amplifiers which
use lots of Golbal NFB are not "good". They are average.

Trevor Wilson

Speaking as one who has never seen, heard, or even smelled an ME amp
perhaps you can clear something up for me. As I understand it the ME is
made up of several modules in the signal path. Each of these modules has
it's own feedback loop.

**Not quite. The amplifier is not all that complex. It is pretty standard,
full complementary symmetry thoughout, dual differential inputs, with the
obligatory active current sources. The Voltage amplifier stage uses around
15dB of Global NFB to stabilise Voltage gain to the desired level. The
Voltage amp feeds the current amplifier, which uses local feedback only (no
loop, from output back to input). The output devices are coupled to the load
via the collectors, rather than the more usual emitter follower
configuration. So, no, each module does not have it's own feedback loop.
Only the Voltage amp has a feedback loop.

Assuming that the module and it's feedback path are correctly
designed and thus pass an undistorted signal to the next downstream
module, why does this require such tight tolerancing in the output stage?

**Because there is no loop feedback around the output stage. Additionally,
the feedback that does operate, is lightly applied.

I do
assume that the ouput stage module has it's own feedback loop and is being
fed an undistorted signal.

**The output stage uses no feedback loop. All feedback is local only. IOW:
Degenerative feedback only.

After all, even with global feedback, I know of
no design that takes the feedback loop back to the input of the pre-amp so
it is not entirely global even in that case.

**The term 'Global NFB' is usually taken to mean that the feedback loop
operates from output to input (of the power amp stage).

Trevor Wilson

[Patrick Turner]

Trevor Wilson wrote:

"Peter Wieck" wrote in message
...
On Apr 27, 8:10 pm, "Trevor Wilson" I'm guessing that Peter Wiek will
have something to say
about your antics as well.

Actually not. I did not read Patrick's reply quite as you did, but
that is not-hardly relevant to the discusion at hand.

**Here are his words, which were directed at you:

"TREVOR WILSON SPEAKS GIBERISH AGAIN."

Since Patrick was responding to YOUR words, he, therefore claimed that you
spoke gibberish.

WRONG TREVOR. I WAS QUITE PLAINLY DELIVERING WORDS OF DISCOURAGEMENT
AT YOU, TREVOR WILSON, WHO SPEAKS GIBERISH MOST DAYS.


Here is something else he said (in response to YOUR words):

"IRELEVANT TWADDLE"

Clearly, Patrick feels that you speak "irelevant twaddle".

LET ME SAY IT PLAINLY AGAIN, WHAT YOU SPEAK IS MAINLY
IRELEVANT TWADDLE.



As to shipping to Australia - one ships by weight at flat increments.
International Priority Mail (United States Postal Service) for a two
pound package - enough for a major bunch of transistors - comes to US$
25.25. About enough for a family of 4 to get fat at McDonalds with not
a great deal of change left over. Nor do I believe for one
hummingbird heartbeat that devices purchased in Australia differ in
any significant way from the same devices from the same maker
purchased in the US. So, somehow, it must get down to how your
suppliers specify their purchases such that the makers send you the
wildly disparate crap and the relatively decent stuff here.

**I provided a list of devices supplied by a Canadian manufacturer and the
Hfe figures. They are far from closely matched.

You, Trevor Wilson, provided a bunch of incorrect misleading muck
about hfe in transistors.

There was no carefully presented case with all the test methods
included.

Hang your head in shame, you deadbeat charlatan Wilson!

Y'all need to broaden your horizons. Y'all need to read back over this
thread and recognize how wildely nonsensical it has become and how
insane your position as-stated really is.

**Which position is that? Please be precise in your answer and refer to MY
position, not what Patrick claims is my position.

YOUR POSITION, TREVOR, IS THAT OF CHIEF BIG FOOL IN THESE GROUPS TO WHOM
YOU SEND YOUR
DAILY BULL****.

How much clearer do you wish us to say it to you?


With all due respect, all
Mr. Stein needs to do is state that any ME-made devices 'service-by-
others' have voided whatever warranty exists

**That is a given.

- however here are the
schematics and service manuals for those of you who wish to understand
the product. And please do NOT attempt to tell me that the
intervention of an outside hand would not be instantly apparent.

**Why should Mr Stein provide service data for all and sundry? Peter
presently provides a fast, effective method of service for all products
manufactured by his company since 1976.

No service manuals exist. Ordinary people like myself could not get a
manual if they tried.

ME service arrangements are the oppsite of what Trevor Wilson is saying.


I should not have to grovel to get service info.

I should not have to go to Trevor Wilson or Peter Stein for ME repairs.

I should be able to buy a manual, or download it.

All about any special matching should be included.

I hate dealing with disreputable liars and bull**** artists like Trevor
Wilson.

The sales of amplifiers other than ME amps looks more assured
the longer this thread runs.

Hell, this is nothing new here in the US. Most every maker from the
sublime to the ridiculous publishes this sort of information as a
matter of course.

**Some do, some don't. Manufacturers are entitled to protect their
intellectual property in any way they see fit.

And they appear utterly stupid to me if they do it like Peter Stein and
yourself.


They are also entitled to
protect the reputation of their product from people like Patrick, who feel
that fitting matched output devices is unnecessary.

"Fitting matched output devices" is a meaningless jargon used by Wilson
when nobody has the slightest idea
what the **** the idiot Wilson is ever saying when the talk goes
technical.
Wilson has NOT said a word about EXACTLY how the tranaistors have been
matched.

The truth is most likely a lot more horribly simple. Ie, transistors
in ME amps are hardly matched at all.

Unless Charlatan Wilson produces proof that devices are matched,
assume they ain't and the talk and claims are all simple lies.


Trevor Wilson is ruining the reputation of ME even further because he
goes right along with the idea of keeping all ME amp techniques a
secret.

If I help ruin ME's reutation, ie, help ruin any chance of further sales
of ME products,
then Peter Stein and Trevor Wilson are to blame, not me, because what I
seek of
EVERYONE AT ALL TIMES is honesty, transparency, detailed arguments,
factual claims,
and workshop manuals with ALL information.


ME deserves all the possible hindrance the world can offer while they
cling to being obstructive,
fulla bull****, and not coming forth with workshop manuals.

Every argument has been tried by Wilson to escape being seen to have
very poor business ethics,
such as mentioning that many other brands also have terrible after sales
support.

The dysfunctionality of other brand names does not in anyway excuse the
ME Technology brand from being arsolic.

When I have any more customers with ME amps, I'll tell them I know of
nobody
who repairs them and that no service information is available.

I for one do not need to service crap for which there are no manuals.

If Peter Stein or Trevor Wilson wish to improve a terrible situtation,
they must prepare either full online info or have manuals printed as
booklets
like other well respected makers.

Failure to do so will NEVER EVER gain my respect.

I don't expect Trevor or Peter to improve their abysmally low standards.
Its typical of such obstinate businessmen.

Patrick Turner.







Trevor Wilson

[Patrick Turner]

keithr wrote:

"Trevor Wilson" wrote in message
...

Good transistor amps function perfectly well with wider tolerances than
you say because of the abundance of
local and other NFB.

**"Good" is your term. not mine. I happen to feel that amplifiers which
use lots of Golbal NFB are not "good". They are average.

Trevor Wilson

Speaking as one who has never seen, heard, or even smelled an ME amp perhaps
you can clear something up for me. As I understand it the ME is made up of
several modules in the signal path. Each of these modules has it's own
feedback loop. Assuming that the module and it's feedback path are correctly
designed and thus pass an undistorted signal to the next downstream module,
why does this require such tight tolerancing in the output stage? I do
assume that the ouput stage module has it's own feedback loop and is being
fed an undistorted signal. After all, even with global feedback, I know of
no design that takes the feedback loop back to the input of the pre-amp so
it is not entirely global even in that case.

Keith

You have invited an utter bull**** artist, ie, Trevor Wilson, to spew
all over you.

Good luck.

Water restrictions prevent me using a hose to clean you up after Trevor
does his bull****ting and spewing.

Note that whatever he says isn't referenced in any way to a schematic of
an ME amp
which you are able to inspect.

It is all sales talk and self agrandisement.

Trevor has never designed or built an amp in the last 30 years.

I seriously doubt Trevor Wilson has ever read a book about amplifier
design in his life.


Your questions require a very well detailed long answer with a schematic
reference,
and this is what you will NEVER GET from a dumb **** like Wilson.

But lemme say that it is supposed by somebody somewhere that well
matched output
transistors assist in getting low crossover distortion switching
artifacts
and low macro artifacts from disimilar hfe and gm on each side of the PP
circuit
where a complementary Ziclai pair of NPN and PNP transistors are used.
The Sziclai output arrangement in ME amp output stage is difficult to
describe in words,
but there is a shirt and trouser load of NFB involved. A schematic is
need to get the picture.
Where output transistors have been paralleled on each side of the PP
circuit
in groups of NPN and groups of PNP types, matching reduces open loop
distortions
if differences between all NPN and between all paralleled PNP are
minimised.
But for full benefits, differences in hfe and gm of PNP AND NPN must
also be considered.

The huge amount of NFB reduces the device differences enormously.

see
http://en.wikipedia.org/wiki/Sziklai_pair

Many amps have PNP and NPN devices in an output stage, and the match
between them is
often very poor indeed, like having an EL34 and a 6L6 in a PP tube amp.

Most ppl wouldn't notice any difference though as the resulting increase
in THD
is marginal only if they are biased at the same idle current.

Its extremely easy to build an emitter follower complementary pair
output stage using NPN and PNP
devices and find that distortion WITHOUT ANY OTHER LOOP OR GLOBAL NFB
becomes inaudible.
This is because the follower connection is an application of about
30 to 40 dB of local series voltage NFB, and the open loop operation of
the same transistors in common
emitter mode, ie, with load in the collector circuit would generate
perhaps 10% THD at clip, and maybe 2% crossover artifacts at low 2 watt
levels,
so when 40dB of follower FB is applied, the 2% becomes 0.02%.

The ME design using Sziclai has a lot of NFB.

It is somewhat similar in principle to

http://www.ampslab.com/c200cfp.htm

In adhering to a 30 year old design Peter Stein lacks any flexability
or fluency in ability to design something different.

The Sziclai isn't especially wonderful, just another of many ways to
hook
up a bunch of transistors.

Matching helps minimise distortions, but only very slightly.

Trevor would have to move mountains to prove otherwise.

see also

http://pirun.ku.ac.th/~fscinrn/Nucle...nt/node97.html

NEVER BUY ME AMPLIFIERS. THERE ARE NO SERVICE MANUALS.




Patrick Turner.

[Patrick Turner]

Trevor Wilson wrote:

"keithr" wrote in message
...

"Trevor Wilson" wrote in message
...

Good transistor amps function perfectly well with wider tolerances than
you say because of the abundance of
local and other NFB.

**"Good" is your term. not mine. I happen to feel that amplifiers which
use lots of Golbal NFB are not "good". They are average.

Trevor Wilson

Speaking as one who has never seen, heard, or even smelled an ME amp
perhaps you can clear something up for me. As I understand it the ME is
made up of several modules in the signal path. Each of these modules has
it's own feedback loop.

**Not quite. The amplifier is not all that complex. It is pretty standard,
full complementary symmetry thoughout, dual differential inputs, with the
obligatory active current sources. The Voltage amplifier stage uses around
15dB of Global NFB to stabilise Voltage gain to the desired level. The
Voltage amp feeds the current amplifier, which uses local feedback only (no
loop, from output back to input). The output devices are coupled to the load
via the collectors, rather than the more usual emitter follower
configuration. So, no, each module does not have it's own feedback loop.
Only the Voltage amp has a feedback loop.

Assuming that the module and it's feedback path are correctly
designed and thus pass an undistorted signal to the next downstream
module, why does this require such tight tolerancing in the output stage?

**Because there is no loop feedback around the output stage. Additionally,
the feedback that does operate, is lightly applied.

I do
assume that the ouput stage module has it's own feedback loop and is being
fed an undistorted signal.

**The output stage uses no feedback loop. All feedback is local only. IOW:
Degenerative feedback only.

Total ****ing bull**** from an ignorant Trevor Wilson!!!

Patrick Turner.

After all, even with global feedback, I know of
no design that takes the feedback loop back to the input of the pre-amp so
it is not entirely global even in that case.

**The term 'Global NFB' is usually taken to mean that the feedback loop
operates from output to input (of the power amp stage).

Trevor Wilson

[keithr]

"Patrick Turner" wrote in message
...


keithr wrote:

"Patrick Turner" wrote in message
...

Hardly anyone here except Phil Allison or myself have any technical
training or experience.

What technical training Patrick? In your own words:-

"In about 1993 my career as a licensed building construction contractor
was
coming to a close because my knees began to fail to keep up with the
creativity with bricks, concrete, lumber, and climbing up ladders.
At that time I had become very interested in my hobby of electronics
while
trying to improve my own sound system. It consisted of a cheap solid
state
receiver and speakers I'd built in 1977 and all designed mainly by
guesswork. During some particularly arduous work on a roof my knees went
on
strike for 9 months, and I could not work hard at all. So I sought to
train
myself in some alternative method of earning a living so for a couple of
years I learnt all I could about vacuum tube amps and speakers, so I
could
try to earn a living from what was a hobby."

Doesn't exactly found like a formal education in electronics to me, I
think
that a number of people here have more training and experience than that.

Keith

Keith, I served my apprenticeship as an amp designer.
Because there wasn't a course at any tech or uni where a degree or
certificate in Triodology
is available, I proceded to qualify myself independantly and privately.

One soon learns to swim after throwing oneself into the deep end.

I have nothing against self tuition, I learned to fix computers (mainframes
not desktop toys) in 3 weeks under pressure, but what you said was "Hardly
anyone here except Phil Allison or myself have any technical training or
experience", and by your own admission you don't have any technical training
in electronics. I don't know what training Phil has, I thought I saw
someting about a uni course, if it was in creative insults then he must have
a PhD.

Much of what i learnt as a construction designer builder was learnt from
vast onsite experience,
and was not just out of a book. I did however become a qualified
carpeter-joiner as a young man and
went on to study at night to get a Building Certificate. Most of what I
knew and used daily
was on the job experience.

I did a 5 year apprenticeship in electronic design. 2 days a week in tech
and 3 days working in the labs of a major governmental research
establishment. I got to work with the likes of Peter J Baxendall, and others
of that sort of level that you would not have heard of.

I have never claimed to have been formerly educated in electronics at
some institution of learning.

"Hardly anyone here except Phil Allison or myself have any technical
training "


I became entirely self taught BEFORE I even got a PC or learnt to type
in 2000.

This doesn't mean I ain't well educated about all the issues surrounding
audio amplifiers.

I wouldn't imply that you don't, but you are no better educated about them
than many others here.

If I had to switch to say radio telescope electronics, i'd be lost until
I learned all about
it all. Takes time.
I believe I could do that if I tried.

A lady of 95 here just got her Master's Degree in Anthropology.

Its remarkable what some folks are able to do.

One guy here I know well became a world expert on hang-glider
aeronautics.
He lived to try out his ideas.
No formal education though.

But did he survive trying out his ideas?

My website now atracts an average of 450 hits daily, mainly from diyer's
wanting to learn,
and because I have tried to make it easy, simple, and well explained
without contradiction.

Its NOT rocket science, or like brain surgery.


Since 2000, there has never been any valid criticism of my site by
anyone except
for the inevitable typing mistake, or minor math mistake which I have
fixed after being informed.

Enough about the web site already, you are getting to sound like Jute,
although I have to say that yours contains a lot more information than his
and at least you do not talk about yourself in the third person.

Meanwhile, where are Trevor Wilson's or Peter Steins' highly informative
websites?

Let's face it your web site is a hobby not a commerial venture, perhaps they
have different hobbies.

They like big noting themselves, and asking the high prices,
but they don't even have workshop manuals, which is the epitome of
poor ethics.

Certainly ME amps cost several times what I would be prepared to pay and
they certainly should have a manual, but I haven't heard that Trevor
overcharges for his repairs.

Keith

[Alan Rutlidge]

"Trevor Wilson" wrote in message
...

"Patrick Turner" wrote in message
...


Trevor Wilson wrote:

"Peter Wieck" wrote in message
...
On Apr 26, 10:41 pm, "Trevor Wilson"
**Except that I was specifically referring to replacing ALL the output
devices in an entire amplifier, yes.

OK... and that would be much like matching tubes - you get a pair/quad
that matches within that pair/quad and is overall within tolerance and
Bob's your uncle. That pair/quad need not match any other pair/quad in
any other amp, just within itself.

??????

TREVOR WILSON SPEAKS GIBERISH AGAIN.

**LOL! You're responding to Peter Weik. I look forward to his response.


So, (picking familiar equipment at random) if I need ten (10) matched
output devices for my Citation 16, I would perhaps have to slog
through maybe 30-40 to get them based on my several experiences with
this process.

**Provided you were not after 1% tolerance, yes.

It is quite likely that of the 20-30 left over, I would
get another ten-set match as well. And any number of pairs/quads.
However, I will also state that I have _NEVER_ had such a catastrophic
failure in my own equipment -though I have seen it in other stuff. I
can only imagine what it would take to create one that did not give
otherwise-warning ahead of time. Yes, a great number of people do not
heed those otherwise-warnings, that is true.

IRELEVANT TWADDLE

**LOL! You're responding to Peter Weik. I look forward to his response.


**I just pulled out a selection of MJ15003 devices I recently tested.
They
were matched by a major manufacturer, for use with their products (They,
too, insist on matched output devices) Here are the results:

Hfe Vbe
24 0.57
35 0.57
40 0.57
37 0.57
79 0.59
82 0.59
36 0.57
91 0.59
30 0.55
73 0.57
80 0.59
69 0.57

TREVOR WILSON ATTEMPTS TO FOLL THE WORLD YET AGAIN WITH LIES AND BS.

**Incorrect. The transistors are here in my workshop. I invite any
interested parties to check my measurements. Even you.


HE DOES NOT TELL US THE TEST CONDITIONS AND TESTING METHOD USED TO
ESTABLISH THE HFE.

**I used my Peak tester. It was done at around 4ma.

Hang on Trevor. Just a few posts ago you siad PS tests his output
transistors at 1A. You're testing at 4mA!
There something wrong with the consistency in the measuring techniques,
isn't there?




TREVOR WILSON IS A COMPLETE FOOL, CHARLATAN, AND ****ING CLOWN.

NOBODY CAN HAVE A RATIONAL CONVERSATION WITH TREVOR WILSON
BECAUSE AFTER 2 MINUTES IT ALL SWAMPED BY BULL****.

**No need to shout, Patrick. Like a petulant child, stamping your feet and
screaming will get you nowhere. If you wish to carry on a logical,
rational discussion, I am always ready. I will not be bullied nor
intimidated by your childish antics. I'm guessing that Peter Wiek will
have something to say about your antics as well.

Trevor Wilson

[roughplanet]

"Arny Krueger" wrote in message
...

"Trevor Wilson" wrote
in message

"roughplanet" wrote in
message ...

"Patrick Turner" wrote in
message ...

I never read what Trevor says about ME amps or the way
transistors are matched because its all empty sales
talk and utter BS.

Is device matching more important in a power amp that lacks loop feedback?

Unequivocally yes!

**Read the above very carefully. THIS is exactly what I
am talking about. Every tech on the planet claims to
know more about ME amplifiers than Peter Stein does.
They WILL NOT fit critically matched devices, even when
specifically instructed to do so. They will always take
the easy (cheap) way out. As a consequence, the
performance and reliability of the product will suffer.
I know. I've seen the messes that have been created by
second rate techs, who think they know it all.

Sounds like a believable story.

To someone as thick as two short planks I'm sure it does.

All the schematics in the world will not help, as long
as techs think they know more than Peter does about his
own product.

Well, they think that he is being hypercautious. We've seen people like
this on this thread.

I know, from my own experience, that some high Global
NFB products benefit from the use of matched devices.
In a product with no Global NFB, the importance of
matching becomes far more crucial.

Agreed.

Gawd TW, You have dug yourself a hole so deep that you
will never get out of it now, no matter what.

More mouth than brains!

Ahh.....the emergence of the Krooborg from his hole in the ground. Church
finish early this evening Arnie?

Why not go away & have a good think about the logic, or
rather, the lack of it in what you have said, and then
come back & TELL THE TRUTH, THE WHOLE TRUTH & ONLY THE
TRUTH to the other members of this group.

If irony killed!

You'd be dead, dead, dead.

You will gain at least some respect; more than if you
just keep banging away at the same old gong, which is
now badly dented & in need of replacing.

I don't think that Trevor is infallible and have crossed swords with him
many times. But, when Trevor is right like this, Trevor deserves respect,
not the derision of fools.

And who are you that your opinion, and that's all you have to offer, is
correct?
Trevor ISN'T right. He's just a BS artiste trying to sell something that
died several years ago but won't lie down.

How can you comment on something you know absolutely nothing about? Have you
ever even seen an ME amp, much less owned one?
I owned one of these amps Arnie, as well as the then matching preamp, and
believe me they were nothing special.

But TW will no doubt tell you that I owned 'an early model' or some such BS
& so my opinion doesn't matter. But the truth is, as Patrick so rightly
says, that both Peter Stein & Trevor Wilson have done very nicely out of ME
'upgrades' & repairs, as without schematics or any other information on
which to rely, other technicians have one hand tied behind their back.

So put up or shut up Arnie. If you know something we don't, then by all
means tell us. If not, better to be thought a fool than open your mouth &
prove it.
But alas, you're way past the point where anyone believes anything you have
to say, a bit like TW.

**Be specific and I will do my best to answer.

Nice come back, Trevor!

Only to a like-minded knowall like you Arnie. The rest of us can see through
his BS, even if you can't.

ruff

[Trevor Wilson[_2_]]

"Alan Rutlidge" wrote in message
...

"Trevor Wilson" wrote in message
...

"Patrick Turner" wrote in message
...


Trevor Wilson wrote:

"Peter Wieck" wrote in message
...
On Apr 26, 10:41 pm, "Trevor Wilson"
**Except that I was specifically referring to replacing ALL the
output
devices in an entire amplifier, yes.

OK... and that would be much like matching tubes - you get a pair/quad
that matches within that pair/quad and is overall within tolerance and
Bob's your uncle. That pair/quad need not match any other pair/quad in
any other amp, just within itself.

??????

TREVOR WILSON SPEAKS GIBERISH AGAIN.

**LOL! You're responding to Peter Weik. I look forward to his response.


So, (picking familiar equipment at random) if I need ten (10) matched
output devices for my Citation 16, I would perhaps have to slog
through maybe 30-40 to get them based on my several experiences with
this process.

**Provided you were not after 1% tolerance, yes.

It is quite likely that of the 20-30 left over, I would
get another ten-set match as well. And any number of pairs/quads.
However, I will also state that I have _NEVER_ had such a catastrophic
failure in my own equipment -though I have seen it in other stuff. I
can only imagine what it would take to create one that did not give
otherwise-warning ahead of time. Yes, a great number of people do not
heed those otherwise-warnings, that is true.

IRELEVANT TWADDLE

**LOL! You're responding to Peter Weik. I look forward to his response.


**I just pulled out a selection of MJ15003 devices I recently tested.
They
were matched by a major manufacturer, for use with their products
(They,
too, insist on matched output devices) Here are the results:

Hfe Vbe
24 0.57
35 0.57
40 0.57
37 0.57
79 0.59
82 0.59
36 0.57
91 0.59
30 0.55
73 0.57
80 0.59
69 0.57

TREVOR WILSON ATTEMPTS TO FOLL THE WORLD YET AGAIN WITH LIES AND BS.

**Incorrect. The transistors are here in my workshop. I invite any
interested parties to check my measurements. Even you.


HE DOES NOT TELL US THE TEST CONDITIONS AND TESTING METHOD USED TO
ESTABLISH THE HFE.

**I used my Peak tester. It was done at around 4ma.

Hang on Trevor. Just a few posts ago you siad PS tests his output
transistors at 1A. You're testing at 4mA!

**Correct. Just to recap:

I don't attempt to match transistors for ME repairs. I buy them from Peter.
I merely listed the above tests to show that transistors vary wildly in Hfe.

There something wrong with the consistency in the measuring techniques,
isn't there?

**In what sense? I was just proving a point about the gain varibility of
transistors. Nothing more.

Trevor Wilson

[TT]

"keithr" wrote in message
...
:
I don't know what training Phil has, I thought I saw
: someting about a uni course, if it was in creative insults
then he must have
: a PhD.
::
: Keith
:
PA attended Sydney Uni in 1971-72 on a fully paid
scholarship and was enrolled in Electrical Engineering. He
never completed it as he dropped out. PA has *NO* formal
qualifications of any sort including not even a drivers
licence. After dropping out he worked for the mob that
repaired a lot of "Flame Linears" where he obviously picked
up a few hints.

Cheers TT

[Trevor Wilson[_2_]]

"roughplanet" wrote in message
...
"Arny Krueger" wrote in message
...

"Trevor Wilson" wrote
in message

"roughplanet" wrote in
message ...

"Patrick Turner" wrote in
message ...

I never read what Trevor says about ME amps or the way
transistors are matched because its all empty sales
talk and utter BS.

Is device matching more important in a power amp that lacks loop
feedback?

Unequivocally yes!

**Read the above very carefully. THIS is exactly what I
am talking about. Every tech on the planet claims to
know more about ME amplifiers than Peter Stein does.
They WILL NOT fit critically matched devices, even when
specifically instructed to do so. They will always take
the easy (cheap) way out. As a consequence, the
performance and reliability of the product will suffer.
I know. I've seen the messes that have been created by
second rate techs, who think they know it all.

Sounds like a believable story.

To someone as thick as two short planks I'm sure it does.

All the schematics in the world will not help, as long
as techs think they know more than Peter does about his
own product.

Well, they think that he is being hypercautious. We've seen people like
this on this thread.

I know, from my own experience, that some high Global
NFB products benefit from the use of matched devices.
In a product with no Global NFB, the importance of
matching becomes far more crucial.

Agreed.

Gawd TW, You have dug yourself a hole so deep that you
will never get out of it now, no matter what.

More mouth than brains!

Ahh.....the emergence of the Krooborg from his hole in the ground. Church
finish early this evening Arnie?

Why not go away & have a good think about the logic, or
rather, the lack of it in what you have said, and then
come back & TELL THE TRUTH, THE WHOLE TRUTH & ONLY THE
TRUTH to the other members of this group.

If irony killed!

You'd be dead, dead, dead.

You will gain at least some respect; more than if you
just keep banging away at the same old gong, which is
now badly dented & in need of replacing.

I don't think that Trevor is infallible and have crossed swords with him
many times. But, when Trevor is right like this, Trevor deserves respect,
not the derision of fools.

And who are you that your opinion, and that's all you have to offer, is
correct?
Trevor ISN'T right. He's just a BS artiste trying to sell something that
died several years ago but won't lie down.

**Nope. But continue anyway.


How can you comment on something you know absolutely nothing about? Have
you ever even seen an ME amp, much less owned one?
I owned one of these amps Arnie, as well as the then matching preamp, and
believe me they were nothing special.

**Really? Let me see if I can locate a cite..............

Here's one:

"In fact, the phono stage in the ME25, custom-built to suit the
impedance of the cartridge you were using, was very good indeed (Oi!!). I
had several plugin modules for different cartridges, and they made the
difference between very good & superb. Peter Stein; someone who gives a
stuff......at a price ;-)."

Any guesses as to the author?





But TW will no doubt tell you that I owned 'an early model' or some such
BS & so my opinion doesn't matter. But the truth is, as Patrick so
rightly says, that both Peter Stein & Trevor Wilson have done very nicely
out of ME 'upgrades' & repairs, as without schematics or any other
information on which to rely, other technicians have one hand tied behind
their back.

**You're not paying close attention. I do not possess a schematic for an
ME850 amplifier. If an audio module fails, I send it to Peter for service.


So put up or shut up Arnie. If you know something we don't, then by all
means tell us. If not, better to be thought a fool than open your mouth &
prove it.
But alas, you're way past the point where anyone believes anything you
have to say, a bit like TW.

**Be specific and I will do my best to answer.

Nice come back, Trevor!

Only to a like-minded knowall like you Arnie. The rest of us can see
through his BS, even if you can't.

**I note that you have yet to provide anything specific. It's pretty much
what I expected.

Trevor Wilson

[Alan Rutlidge]

"keithr" wrote in message
...

"Patrick Turner" wrote in message
...


keithr wrote:

"Patrick Turner" wrote in message
...

Hardly anyone here except Phil Allison or myself have any technical
training or experience.

What technical training Patrick? In your own words:-

"In about 1993 my career as a licensed building construction contractor
was
coming to a close because my knees began to fail to keep up with the
creativity with bricks, concrete, lumber, and climbing up ladders.
At that time I had become very interested in my hobby of electronics
while
trying to improve my own sound system. It consisted of a cheap solid
state
receiver and speakers I'd built in 1977 and all designed mainly by
guesswork. During some particularly arduous work on a roof my knees went
on
strike for 9 months, and I could not work hard at all. So I sought to
train
myself in some alternative method of earning a living so for a couple of
years I learnt all I could about vacuum tube amps and speakers, so I
could
try to earn a living from what was a hobby."

Doesn't exactly found like a formal education in electronics to me, I
think
that a number of people here have more training and experience than
that.

Keith

Keith, I served my apprenticeship as an amp designer.
Because there wasn't a course at any tech or uni where a degree or
certificate in Triodology
is available, I proceded to qualify myself independantly and privately.

One soon learns to swim after throwing oneself into the deep end.

I have nothing against self tuition, I learned to fix computers
(mainframes not desktop toys) in 3 weeks under pressure, but what you said
was "Hardly anyone here except Phil Allison or myself have any technical
training or experience", and by your own admission you don't have any
technical training in electronics. I don't know what training Phil has, I
thought I saw someting about a uni course, if it was in creative insults
then he must have a PhD.

Just for the record. I have a Dipl. in Electronic Engineering. Several
years study at technical college as it was known in those days.
I've attended more manufacturer's specialist courses than I care to
remember.
I don't think it makes me any better or worse than others similarly
qualified who post in this NG.

Phil apparently attend uni on a scholarship but never stuck it out to gain
any recognised qualification.
Most of his knowledge I would suspect was gained from the school of hard
knocks so to say.
There is almost no doubt in my mind he is quite knowledgeable in the field.
His only obvious downfall is his social ineptness and an inability to
communicate without it turning into a foul mouthed mud slinging match. :-(
As such he has earned the tag "Toaster tech". No doubt a term of endearment
he rather not have.

I've designed and built the odd pre-amp and power amp. I do it as a hobby.
A very part time hobby at that.
I'm no expert and don't claim to be. There is much to be learned as
technology evolves.
In my day to day work I have to keep my finger on the pulse of the
technologies I lecture in.
Unfortunately that doesn't involve as much electronics these days, and
certaingy not linear audio amplifiers.

Cheers,
Alan

[roughplanet]

"Trevor Wilson" wrote in message
...

"roughplanet" wrote in message
...

"Arny Krueger" wrote in message
...

"Patrick Turner" wrote in
message ...

I never read what Trevor says about ME amps or the way
transistors are matched because its all empty sales
talk and utter BS.

Is device matching more important in a power amp that lacks loop
feedback?

Unequivocally yes!

**Read the above very carefully. THIS is exactly what I
am talking about. Every tech on the planet claims to
know more about ME amplifiers than Peter Stein does.
They WILL NOT fit critically matched devices, even when
specifically instructed to do so. They will always take
the easy (cheap) way out. As a consequence, the
performance and reliability of the product will suffer.
I know. I've seen the messes that have been created by
second rate techs, who think they know it all.

Sounds like a believable story.

To someone as thick as two short planks I'm sure it does.

All the schematics in the world will not help, as long
as techs think they know more than Peter does about his
own product.

Well, they think that he is being hypercautious. We've seen people like
this on this thread.

I know, from my own experience, that some high Global
NFB products benefit from the use of matched devices.
In a product with no Global NFB, the importance of
matching becomes far more crucial.

Agreed.

Gawd TW, You have dug yourself a hole so deep that you
will never get out of it now, no matter what.

More mouth than brains!

Ahh.....the emergence of the Krooborg from his hole in the ground. Church
finish early this evening Arnie?

Why not go away & have a good think about the logic, or
rather, the lack of it in what you have said, and then
come back & TELL THE TRUTH, THE WHOLE TRUTH & ONLY THE
TRUTH to the other members of this group.

If irony killed!

You'd be dead, dead, dead.

You will gain at least some respect; more than if you
just keep banging away at the same old gong, which is
now badly dented & in need of replacing.

I don't think that Trevor is infallible and have crossed swords with him
many times. But, when Trevor is right like this, Trevor deserves
respect, not the derision of fools.

And who are you that your opinion, and that's all you have to offer, is
correct?
Trevor ISN'T right. He's just a BS artiste trying to sell something that
died several years ago but won't lie down.

**Nope. But continue anyway.

How can you comment on something you know absolutely nothing about? Have
you ever even seen an ME amp, much less owned one?
I owned one of these amps Arnie, as well as the then matching preamp, and
believe me they were nothing special.

**Really? Let me see if I can locate a cite..............
Here's one:
"In fact, the phono stage in the ME25, custom-built to suit the
impedance of the cartridge you were using, was very good indeed (Oi!!). I
had several plugin modules for different cartridges, and they made the
difference between very good & superb. Peter Stein; someone who gives a
stuff......at a price ;-)."

Any guesses as to the author?

Yep me, but I was talking about the phono stage, a small plug in board, and
nothing else. The rest of the ME25 was, as I said, nothing special. When
offered a Rose (tube) preamp, which really was a pearler, I dropped the ME25
like a hot scone.

But TW will no doubt tell you that I owned 'an early model' or some such
BS & so my opinion doesn't matter. But the truth is, as Patrick so
rightly says, that both Peter Stein & Trevor Wilson have done very nicely
out of ME 'upgrades' & repairs, as without schematics or any other
information on which to rely, other technicians have one hand tied behind
their back.

**You're not paying close attention. I do not possess a schematic for an
ME850 amplifier. If an audio module fails, I send it to Peter for service.

I wasn't talking about an ME850 as you well know TW, I was referring to the
ME750 that I owned. When I last mentioned that fact, your reply was along
the lines of 'yes, but that was an early model which was greatly improved by
a subsequent upgrade'

The 'subsequent upgrade' was from a 750 to an 850, and I'd be lying if I
said I could remember the cost. But what I can remember is that it was
pretty darn expensive, and PS was attempting to get a production run of them
before beginning the upgrades. If you missed the boat, both the time to
perform the upgrade & the cost blew out to something that was out of the
question.

I smelt a rat & decided I could do better with my dollar, and bought a pair
of Tube Technology 100 watt monoblocs, which I later sold to buy the (don't
read this; you'll only get upset) 35 watt SET amp that I am still using
today.

So put up or shut up Arnie. If you know something we don't, then by all
means tell us. If not, better to be thought a fool than open your mouth &
prove it.
But alas, you're way past the point where anyone believes anything you
have to say, a bit like TW.

**Be specific and I will do my best to answer.

Nice come back, Trevor!

Only to a like-minded knowall like you Arnie. The rest of us can see
through his BS, even if you can't.

**I note that you have yet to provide anything specific. It's pretty much
what I expected.

What you expect is invariably what you'll get TW. The BS that you've told
has finally grown to the point where it has bitten you on the bum.
You're just another crazy control freak who can never be wrong, even when
you are. This newsgroup has quite a few now, so you'll never be lonely.
Cheers,

ruff

[roughplanet]

"Alan Rutlidge" wrote in message
...

"keithr" wrote in message
...

"Patrick Turner" wrote in message
...

Hardly anyone here except Phil Allison or myself have any technical
training or experience.

What technical training Patrick? In your own words:-

"In about 1993 my career as a licensed building construction contractor
was coming to a close because my knees began to fail to keep up with
the creativity with bricks, concrete, lumber, and climbing up ladders.
At that time I had become very interested in my hobby of electronics
while trying to improve my own sound system. It consisted of a cheap
solid state receiver and speakers I'd built in 1977 and all designed
mainly by guesswork. During some particularly arduous work on a roof my
knees went on
strike for 9 months, and I could not work hard at all. So I sought to
train myself in some alternative method of earning a living so for a
couple of years I learnt all I could about vacuum tube amps and
speakers, so I could try to earn a living from what was a hobby."

Doesn't exactly found like a formal education in electronics to me, I
think that a number of people here have more training and experience
than that.

Keith, I served my apprenticeship as an amp designer.
Because there wasn't a course at any tech or uni where a degree or
certificate in Triodology
is available, I proceded to qualify myself independantly and privately.

One soon learns to swim after throwing oneself into the deep end.

I have nothing against self tuition, I learned to fix computers
(mainframes not desktop toys) in 3 weeks under pressure, but what you
said was "Hardly anyone here except Phil Allison or myself have any
technical training or experience", and by your own admission you don't
have any technical training in electronics. I don't know what training
Phil has, I thought I saw someting about a uni course, if it was in
creative insults then he must have a PhD.

Just for the record. I have a Dipl. in Electronic Engineering. Several
years study at technical college as it was known in those days.
I've attended more manufacturer's specialist courses than I care to
remember.
I don't think it makes me any better or worse than others similarly
qualified who post in this NG.

Phil apparently attend uni on a scholarship but never stuck it out to gain
any recognised qualification.
Most of his knowledge I would suspect was gained from the school of hard
knocks so to say.
There is almost no doubt in my mind he is quite knowledgeable in the
field.
His only obvious downfall is his social ineptness and an inability to
communicate without it turning into a foul mouthed mud slinging match. :-(
As such he has earned the tag "Toaster tech". No doubt a term of
endearment he rather not have.

I've designed and built the odd pre-amp and power amp. I do it as a
hobby. A very part time hobby at that.
I'm no expert and don't claim to be. There is much to be learned as
technology evolves.
In my day to day work I have to keep my finger on the pulse of the
technologies I lecture in.
Unfortunately that doesn't involve as much electronics these days, and
certaingy not linear audio amplifiers.

Ohhhh..............you'd LOVE the linear amplifier that I have sitting in my
shack at the moment Alan, all 3kW of it. Once midnight strikes, I'll turn it
on.
Hope I don't turn into......PA :-).

ruff

[Phil Allison]

"Trevor Wilson"

**Correct. Just to recap:

I don't attempt to match transistors for ME repairs. I buy them from
Peter. I merely listed the above tests to show that transistors vary
wildly in Hfe.


** You have shown no such thing with a meaningless test with that unsuitable
" Peak " meter - which is clearly intended for small signal devices.

The Hfe of high power BJTs typically falls off sharply below 100mA Ic.

The very same group of MJ15003s will likely test very close in Hfe at an Ic
of 250mA or more.





....... Phil

[atec77[_2_]]

Trevor Wilson wrote:
"Alan Rutlidge" wrote in message



..


HE DOES NOT TELL US THE TEST CONDITIONS AND TESTING METHOD USED TO
ESTABLISH THE HFE.
**I used my Peak tester. It was done at around 4ma.
Hang on Trevor. Just a few posts ago you siad PS tests his output
transistors at 1A. You're testing at 4mA!

**Correct. Just to recap:

I don't attempt to match transistors for ME repairs. I buy them from Peter.
I merely listed the above tests to show that transistors vary wildly in Hfe.

There something wrong with the consistency in the measuring techniques,
isn't there?

**In what sense? I was just proving a point about the gain varibility of
transistors. Nothing more.
you lied by omission , a VERY common ploy on your part .

Trevor Wilson

[keithr]

"Patrick Turner" wrote in message
...


keithr wrote:

snip irelevants,

To change the situation, Peter Stein should produce manuals
for sale, and give all schematics and explanations and
include the simple methods of matching the transistors.

There certainly should be a manual available at a reasonable price, but
this
is one of the problems with boutique manufacturers, they can't usually
afford a technical writer to do the job, and the last person that you
want
doing it is the designer.

Wrong.

sorry but I have to disagree as someone who has been there and done that.

Peter Stein has once appeared on the news groups to slow up the bull****
stream from Trevor
Wilson. Its was not a happy episode.

Stein has no trouble typing plain english, and would, like myself, have
no trouble
whatsover drafting up a comprehensive manual.

He would do it better than an employed writer who would, without Peter's
knowledge, make a cock up of the manual.

You obviously have never participated in a major commercial project. I have
see the crap that designers wrote, then the tranformation that a
professional technical writer could bring to it. It is an iterative process
that may take a couple of cycles between the designers and the writer to
asrrive at something that satisfies everybody, but the result is far better
than the designers would do themselves. Part of the process is getting the
designers to explain their work to someone who knows nothing about the
project, that focusses the mind wonderfully

I didn't need some dumb & expensive writer **** to write my website and
draw up all the schematics.

If you cannot and or will not write up your own
true story about your productions then something is very wrong.

In my experience, few designers do a good job of it.

include the simple methods of matching the transistors.

Far better to design curcuits that do not require component matching to
within 1%

People wanting to own an ME 850 amp should get a far better deal
than they get now for their $6,000.

Yes like $4000 change.

Peter Stein doesn't care that his product appeals to only a tiny itzt
bitzy
weeny percentage of ppl.

He must think he can "hang out" for the big price.

However, I could also be accused of charging too much per watt.

But the work I do for $6,000 is vastly more than whatever Peter Stein
does.

Any SS amp is child's play to make compared to a serious tube amp.

Why?

Then it depends who you compare me to. Some chinese makers are selling
5050 Watt stereo tube4 amps on-line
and direct from the maker without western round eye arsole middlemen for
$700.

But they are junk, and badly made.

I have owned several Japanese SS amps costing 10-20% of an ME and have never
had the least trouble with any of them, the only reason that they have been
replaced is to get something a little better.

The Real Mccoy is much more expensive.

I don't care if you make steam engines forsale. Good luck if you do.

But if you didn't have the service information about your engines, i'd
be right onto you.

If you can't service your own steam engine without help, you shouldn't be
owning one. I don't think that Watt had a web site.

My overwhelming concern in this thread is that
Peter Stein and that idiot fool Trevor Wilson fail to see that its
necessary to have all constructional information and schematics of their
products
either available online for free or available as a hard copy workshop
service manual for a fee.

Trevor accuses me of SHOUTING but he spews mountains of utter lies,
bull****,
and nothing really informative at all.

He has never designed or built an amp in his life,
but poses as a know all.

The pair of you are as bad as each other. Peronally, I never built a
mainframe computer but I was damn good at fixing them mainly because I had a
good understanding of the principles involved (and had a complete set of
logics).

Keith

[keithr]

"Trevor Wilson" wrote in message
...

"keithr" wrote in message
...

"Trevor Wilson" wrote in message
...

Good transistor amps function perfectly well with wider tolerances than
you say because of the abundance of
local and other NFB.

**"Good" is your term. not mine. I happen to feel that amplifiers which
use lots of Golbal NFB are not "good". They are average.

Trevor Wilson

Speaking as one who has never seen, heard, or even smelled an ME amp
perhaps you can clear something up for me. As I understand it the ME is
made up of several modules in the signal path. Each of these modules has
it's own feedback loop.

**Not quite. The amplifier is not all that complex. It is pretty standard,
full complementary symmetry thoughout, dual differential inputs, with the
obligatory active current sources. The Voltage amplifier stage uses around
15dB of Global NFB to stabilise Voltage gain to the desired level. The
Voltage amp feeds the current amplifier, which uses local feedback only
(no loop, from output back to input). The output devices are coupled to
the load via the collectors, rather than the more usual emitter follower
configuration. So, no, each module does not have it's own feedback loop.
Only the Voltage amp has a feedback loop.

Assuming that the module and it's feedback path are correctly
designed and thus pass an undistorted signal to the next downstream
module, why does this require such tight tolerancing in the output stage?

**Because there is no loop feedback around the output stage. Additionally,
the feedback that does operate, is lightly applied.

I do
assume that the ouput stage module has it's own feedback loop and is
being fed an undistorted signal.

**The output stage uses no feedback loop. All feedback is local only. IOW:
Degenerative feedback only.

Maybe a little feedback around the output stage would eliminate the need for
such close matching without changing the sound, but I suppose that in audio,
everybody has to have their own gimmick to differentiate their product.

After all, even with global feedback, I know of
no design that takes the feedback loop back to the input of the pre-amp
so it is not entirely global even in that case.

**The term 'Global NFB' is usually taken to mean that the feedback loop
operates from output to input (of the power amp stage).

Trevor Wilson

[Arny Krueger]

"roughplanet" wrote in
message
"Arny Krueger" wrote in message
...

"Trevor Wilson" wrote
in message

"roughplanet" wrote in
message
...
"Patrick Turner" wrote in
message ...

I never read what Trevor says about ME amps or the
way transistors are matched because its all empty
sales talk and utter BS.

Is device matching more important in a power amp that
lacks loop feedback?

Unequivocally yes!

**Read the above very carefully. THIS is exactly what
I am talking about. Every tech on the planet claims to
know more about ME amplifiers than Peter Stein does.
They WILL NOT fit critically matched devices, even
when specifically instructed to do so. They will
always take the easy (cheap) way out. As a
consequence, the performance and reliability of the
product will suffer. I know. I've seen the messes
that have been created by second rate techs, who
think they know it all.

Sounds like a believable story.

To someone as thick as two short planks I'm sure it does.

Long on childish name-calling, short on relevant facts. Where did you get
your EE from, a cereal box? ;-)

All the schematics in the world will not help, as long
as techs think they know more than Peter does about
his own product.

Well, they think that he is being hypercautious. We've
seen people like this on this thread.

I know, from my own experience, that some high Global
NFB products benefit from the use of matched devices.
In a product with no Global NFB, the importance of
matching becomes far more crucial.

Agreed.

Gawd TW, You have dug yourself a hole so deep that you
will never get out of it now, no matter what.

More mouth than brains!

Ahh.....the emergence of the Krooborg from his hole in
the ground. Church finish early this evening Arnie?

Why not go away & have a good think about the logic, or
rather, the lack of it in what you have said, and then
come back & TELL THE TRUTH, THE WHOLE TRUTH & ONLY THE
TRUTH to the other members of this group.

If irony killed!

You'd be dead, dead, dead.

More childish name-calling, still no relevant technical comments.

You will gain at least some respect; more than if you
just keep banging away at the same old gong, which is
now badly dented & in need of replacing.

I don't think that Trevor is infallible and have crossed
swords with him many times. But, when Trevor is right
like this, Trevor deserves respect, not the derision of
fools.

And who are you that your opinion, and that's all you
have to offer, is correct?

Just a graduate engineer with 40 years of relevant experience.

Trevor ISN'T right.

On the technical point, he is.

He's just a BS artiste trying to sell
something that died several years ago but won't lie down.

That's a different issue.

How can you comment on something you know absolutely
nothing about?

You've shown me how? ;-)

Have you ever even seen an ME amp, much
less owned one?

I don't need to own a zero loop FB SS amp to know something of their care
and feeding.

I owned one of these amps Arnie, as well as the then
matching preamp, and believe me they were nothing special.

That's a different issue.

But TW will no doubt tell you that I owned 'an early
model' or some such BS & so my opinion doesn't matter.

Given your inability to understand audio technology, your opinion is
geneally wrong.

But the truth is, as Patrick so rightly says, that both
Peter Stein & Trevor Wilson have done very nicely out of
ME 'upgrades' & repairs, as without schematics or any
other information on which to rely, other technicians
have one hand tied behind their back.

That's a different issue.

So put up or shut up Arnie. If you know something we
don't, then by all means tell us.

Been there, done that. You spit on it.

If not, better to be
thought a fool than open your mouth & prove it.
But alas, you're way past the point where anyone believes
anything you have to say, a bit like TW.

That's your problem.

**Be specific and I will do my best to answer.

Nice come back, Trevor!

Only to a like-minded knowall like you Arnie. The rest of
us can see through his BS, even if you can't.

I'm only addressing the technical issue of the need for careful selection of
devices in a zero loop NFB amp.