Friends, rodents and other tubies, hail!

The KISS AMP 300B project:
http://members.lycos.co.uk/fiultra/T...mp%20INDEX.htm
is one of many DIY tube and solid state amp projects, and also point
source speakers, at JUTE ON AMPS:
http://members.lycos.co.uk/fiultra/JUTE%20ON%20AMPS.htm

Here is a mainly visual progress report for one of the two amps in The
KISS AMP 300B project:
T39 single tube input/driver stage proving prototype:
http://members.lycos.co.uk/fiultra/K...0T68MZ417A.jpg
Driver stage circuit (potato amp made by subtracting 300B):
http://members.lycos.co.uk/fiultra/t...17acircuit.jpg
Layout suitable for potato (T68) version only (latest hi-cap filter
version of T39 will not fit; the new caps -- see below -- are too fat
to fit between the second choke and the output tranny at the top of the
page)
http://members.lycos.co.uk/fiultra/t68bismzlayout.jpg
Circuit of T39 KISS Amp:
http://members.lycos.co.uk/fiultra/T...trafi-crct.jpg
Transfer function for the KISS T39 Amp for those of you who want to
calculate along with Rudy (go on, surprise yourself by discovering how
little distortion there can be in a SET amp):
http://members.lycos.co.uk/fiultra/112KISScurves.jpg
What lies behind the curves -- the neddy introduction:
http://members.lycos.co.uk/fiultra/K...dre%20Jute.htm
Teach yourself to evaluate transfer curves:
http://members.lycos.co.uk/fiultra/K...dre%20Jute.htm
The KISS T39 original (low-cap) prototype (since transformed into T68
potato above; the interstage transformers shown in the T68 layout went
in the space occupied by big turreted ceramic UX4 sockets for the 300B
in the T39 -- before you ask, the T39 is silent enough without IST):
http://members.lycos.co.uk/fiultra/t39kiss001.jpg
More illustrations:
http://members.lycos.co.uk/fiultra/KISS%20190.htm

An amp like the T39 KISS AMP is not built in isolation:
My DIY horns and other sensitive point source speaker designs for the
KISS 300B amps:
http://members.lycos.co.uk/fiultra/K...20T91HWAF3.jpg
http://members.lycos.co.uk/fiultra/K...Impresario.jpg

For a giggle, five files on a moderately economical fun experiment to
approach DHT sound with a transistor amp:
http://members.lycos.co.uk/fiultra/K...dre%20Jute.htm
http://members.lycos.co.uk/fiultra/K...dre%20Jute.htm
http://members.lycos.co.uk/fiultra/K...20mGBschem.jpg
http://members.lycos.co.uk/fiultra/K...%20mGBmatr.jpg
http://members.lycos.co.uk/fiultra/K...%20NoBleed.jpg

Next I shall design the layout and appearance of the final version, for
which I have a copper plate 13in wide by 1m long.

I'm still trying to use a 17x10x4in Hammond box as a cover for the
gubbins. I'm keen on the Hammond chassis as a cover idea because that
is a promise I made with the original Lundahl Modular Amp series, of
which the other KISS amp, the T44 (circuit and frequency response in
these links, description in main KISS materials) is a development.
http://members.lycos.co.uk/fiultra/T44bis-'Populaire'-crct.jpg
http://members.lycos.co.uk/fiultra/T...x-6SN7-FQ-.jpg

But Patrick's contribution to the T39 power filter (thanks a bunch for
causing me endless trouble, Patrick!), and help from Triode Supply
Japan in finding aliminium cannisters of suitable Solen polyprop
values, have resulted in much more component footage than I originally
contemplated. The original layout, on the left of the photographs he
http://members.lycos.co.uk/fiultra/K...0T68MZ417A.jpg
and in full he
http://members.lycos.co.uk/fiultra/t68bismzlayout.jpg
was already tighter than I like for a circuit published for DIYers. I
might go back to my multilayer 'pagoda' design idea except that I built
a sort of X-plane amp a few years ago, for standing on the cross end
with the tubes sideways on, and soldering in the narrow space between
the plates was a pig; the pagoda design would also require final
soldering in narrow spaces. Well see.

Andre Jute
Jute on Amps at http://members.lycos.co.uk/fiultra/
"wonderfully well written and reasoned information
for the tube audio constructor"
John Broskie TubeCAD & GlassWare
"an unbelievably comprehensive web site
containing vital gems of wisdom"
Stuart Perry Hi-Fi News & Record Review

Andre Jute wrote:

Friends, rodents and other tubies, hail!

The KISS AMP 300B project:
http://members.lycos.co.uk/fiultra/T...mp%20INDEX.htm
is one of many DIY tube and solid state amp projects, and also point
source speakers, at JUTE ON AMPS:
http://members.lycos.co.uk/fiultra/JUTE%20ON%20AMPS.htm

Here is a mainly visual progress report for one of the two amps in The
KISS AMP 300B project:
T39 single tube input/driver stage proving prototype:
http://members.lycos.co.uk/fiultra/K...0T68MZ417A.jpg
Driver stage circuit (potato amp made by subtracting 300B):
http://members.lycos.co.uk/fiultra/t...17acircuit.jpg

If the two JPGs above are any indication of the progress of this project,
you are in deep ****.

And what about all those names of suppliers of bits & pieces on the LHS of
the schematic? What have they to do with your flaky efforts? Are they on
the schematic to somehow boost your questionable reputation by association?
Did you ask for permission to include them?

Better take up cooking on a full time basis!

Puzzled to say the least by all the Bandwidth you have occupied over the
last while on RAT. Better known as 'Verbal Diarrhea' by
some! John Stewart

This sort of snippy and uninformative response-- no technical content,
no entertainment value, only unimpresive vitriol -- is typical of what
in future in shall simply ignore. I started this thread in an effort to
return this conference to technical matters and the first response is a
nasty little piece of non-technical spite from someone who would
benefit by the reversion. Sheesh! -- Andre Jute

John Stewart wrote:
Andre Jute wrote:

Friends, rodents and other tubies, hail!

The KISS AMP 300B project:
http://members.lycos.co.uk/fiultra/T...mp%20INDEX.htm
is one of many DIY tube and solid state amp projects, and also point
source speakers, at JUTE ON AMPS:
http://members.lycos.co.uk/fiultra/JUTE%20ON%20AMPS.htm

Here is a mainly visual progress report for one of the two amps in The
KISS AMP 300B project:
T39 single tube input/driver stage proving prototype:
http://members.lycos.co.uk/fiultra/K...0T68MZ417A.jpg
Driver stage circuit (potato amp made by subtracting 300B):
http://members.lycos.co.uk/fiultra/t...17acircuit.jpg

If the two JPGs above are any indication of the progress of this project,
you are in deep ****.

And what about all those names of suppliers of bits & pieces on the LHS of
the schematic? What have they to do with your flaky efforts? Are they on
the schematic to somehow boost your questionable reputation by association?
Did you ask for permission to include them?

Better take up cooking on a full time basis!

Puzzled to say the least by all the Bandwidth you have occupied over the
last while on RAT. Better known as 'Verbal Diarrhea' by
some! John Stewart

Why do you still have some 100 watts of dropping resistors on the
secondary side of the transformer?

http://members.lycos.co.uk/fiultra/t...17acircuit.jpg

Peter Wieck
Wyncote, PA

That's excellent timing, Peter. I unkillfiled everyone to see who wants
to work and who is a permanent flame merchant -- and there you are with
a useful question. Give that boy's young lady the pink fluffy rabbit.

wrote:
Why do you still have some 100 watts of dropping resistors on the
secondary side of the transformer?

http://members.lycos.co.uk/fiultra/t...17acircuit.jpg

Peter Wieck
Wyncote, PA

"still" ? Always been there.

The resistors I used are overrated (see below) and my associate who
reverse-engineered the little amp for the schematic wrote in the rating
they are rather than the ratings they should have been probably because
I forgot to tell him to recalculate everything. Now that you've pointed
it out to me, I've put the right ratings in the posted version.
http://members.lycos.co.uk/fiultra/t...17acircuit.jpg
Thanks for the heads-up. While we're here, we may as well discuss
resistors in secondaries, and dropping resistors in general.

I made the T68bis potato amp by stripping out a pair of 300B on a proto
and using my junkbox resistors to drop the voltages. When the little
amp goes out of the door or is stripped down, they go back in the
junkbox. My only concern at the time was that they were the right value
and overrated for the job.

NB: A 50W resistor doesn't dissipate 50W just because it is rated 50W.
The heat it dissipates is related to current flowing through it and the
resistance value. Colonel Ohm saves the day again:
P = I*I*R -- says nothing about the rating of the resistor which by
tradition is 2 or 3 times the dissipation arrived at for a safety
margin.

There are many reasons for using a resistor of the right value and a
higher rating.

1. You have it in junkbox already and don't need to wait for a delivery
from your component pusher.

2. The manufacturer doesn't make all the values in all the ratings, or
your supplier doesn't stock the full range, so you buy the value you
need in the next higher rating.

3. I like big chunky aliminium-cased resistors because they're
cool-running with all that area and fins besides.

4. In the case of at least one of the resistors you think over-rated,
the alternative was a nasty cement-cased pluggable resistor of the
right rating. I like neither the looks nor the sound of those.

5. The standard resistor I keep in all values and both the available
ratings is Kiwame. It gets a bit expensive sticking them in where they
won't make a difference to the sound.

6. I'm designing for DIYers. The great thing is not to give Joe Doe a
chance to say near enough is good enough and put an underrated part in.
Better safe than sorry.

7. Those particular resistors derate to 50 per cent (IIRC, look it up
if you don't know -- *that* is why I overrate them!) or less if they
aren't on a heatsink, if they aren't in free air, etc. What you see
isn't a 100W of power capability but only 50W inside a case, maybe
less. It is for tricky little subtleties like this that Patrick wants
people to hit the books rather than learn only by soldering.

8. It isn't so widely known that resistors have voltage ratings. It is
not uncommon, though less so these days of CE marks over here, to see
amps built with resistors that at least theoretically could burst into
flames any moment. Those ali-cased resistors I like have very
attractive voltage ratings too, so they live naturally in the junkbox
of someone who moves casually from a little 175V 417A potato amp to a
kilovolt-plus 845 or SV572.xx amp. The ali-cased resistors save the
bother of having to check the voltage spec of some orphan resistor from
the junkbox; I've long since cleared all the low-voltage stuff from my
junkbox.

****

Returning now to the particular resistors you mention, the two 330R in
the mains secondary are ballasts. In a tube rectifier circuit you're
supposed to have those, usually about 75R minimum. Check the spec
sheets for various tube rectifiers, on some of which is an explanation
and schematic of the equivalent circuit for various impedances in and
around a tube rectifier (for each type of filter, cap input and choke
input) and their effects.

I have long since found that a pair of stiff ballasts smooths the power
an agreeable fraction when you have a hefty bleed already.

*******

Remember this: the idea isn't a perfect schematic but to build
something, to listen, to develop it. I used to waste lots of time
agonising over the perfect paper design and collecting all the perfect
parts. Now as often as not I build the prototype on the fly with a few
calculations on the logarithmic bezels of my watch (why is a rotary
slide rule still called a "rule" -- tell me that and I'll think you
clever) to check my mental arithmetic, then develop it right, and only
then reverse engineer the amp to draw the schematic of the circuit.
There are a few traps in that, as we have seen, when sharp eyes catch
out your overrated junkbox parts but the amp gets done a lot sooner.

The secret of designing good-sounding amps and still have time left to
listen to music is to fail fast. Anyone who hasn't failed often, never
mind "never" as too many claim, probably can't distinguish mud from
music.

Andre Jute
Visit Jute on Amps at http://members.lycos.co.uk/fiultra/
"wonderfully well written and reasoned information
for the tube audio constructor"
John Broskie TubeCAD & GlassWare
"an unbelievably comprehensive web site
containing vital gems of wisdom"
Stuart Perry Hi-Fi News & Record Review

It would be useful to know the secondary voltage at that transformer
before the resistors are added, so as to get the 180V rectified voltage
you require. Yes, you have 500V ~500ma at the bottom, I assume that is
across the entire two coils (5-to-7) and not to the (virtual)
center-tap, but that too would be helpful to know.

Assuming that you are getting 250V/Coil at your stated input, the way I
read your output from the rectifier tube, that would come to some 415V
or so out of the 5AR4/GZ34, excepting the dropping resistors. So, how
did the value of 660 ohms of total AC resistance get chosen, especially
in light of the 4700 ohm bleeder resistor further down the line (at 25
watts) to get to the required 180V? And 'adding a small capacitor' to
adjust voltage... this is an iffy (albeit nearly heatless) expedient,
'cause if that cap should fail, *poof*. So, it would be useful to know
the required/expected voltages right down the line so that the correct
choices might be made.

Would it not be much simpler to drop the primary side to ~220V or so,
thereby almost eliminating the need for filament-voltage dropping
resistors excepting getting 5V on the rectifier? SWAG, assuming 230
single-phase hot/neutral at the primary, and about a 2A (allowing for
losses) total load shouldn't take much of a single dropping resistor to
get that 220V, or even slightly less. This way, individuals in other
countries with different standards could work to the required
_secondary_ voltages based on their wallplate voltage. If one is fond
of iron, either a small autotransformer or a small bucking transformer
could be used ILO a resistor for less heat.

This might also greatly simplify the requirements for your B+ side?

Two chokes? Why? The 5AR4 is a pretty good, quite rugged (if expensive)
rectifier. And it would seem simpler to add additional capacitance on
the line-side of the first choke, thereby eliminating the need for the
second? With all your prior losses, you are running well below the
saturation level of a single unit (400/575ma). 500V caps are cheap
these days, even 50uF or better, certainly cheaper than iron. And if
all you want to filter is 50/60Hz chop, one will do fine. As a small
aside, the 5U4 rectifier is much cheaper, albeit not quite as rugged
and without the slow-start characteristics that distinguish the 5AR4.
But in any case, a single choke with sufficient capacitance would drop
any chop way below other noise sources.

Are you familiar with Mad Man Muntz? He would go into his skunk-works
whenever his engineers decided they had a new product to develop, and
start cutting out parts (he was an excellent EE, so this was not done
at random) until whatever-it-was stopped working. *That* was the magic
point from which to design.

I question from the perspective of one who is usually presented with
smoking ruins and given the mandate to 'make it work'. Many times
without benefit of schematics, or if they are available, facing so many
whimsical modifications to make the schematics of dubious value. So,
"expected" and "actual" values are important things to know. At times,
I thank my lucky stars that this is a hobby.... so I do not have to
make a living at it. Otherwise, not 1 unit in 10 that I see would be
worth the time and trouble to fix.

Peter Wieck
Wyncote, PA

Hi Andre,

This is a superb reply to a dumb question that I would have thought PFJW
would have already known the answer to, given his background. You
thoroughly covered all the bases.


Regards,

John Byrns


In article .com, "Andre
Jute" wrote:

That's excellent timing, Peter. I unkillfiled everyone to see who wants
to work and who is a permanent flame merchant -- and there you are with
a useful question. Give that boy's young lady the pink fluffy rabbit.

wrote:
Why do you still have some 100 watts of dropping resistors on the
secondary side of the transformer?

http://members.lycos.co.uk/fiultra/t...17acircuit.jpg

Peter Wieck
Wyncote, PA

"still" ? Always been there.

The resistors I used are overrated (see below) and my associate who
reverse-engineered the little amp for the schematic wrote in the rating
they are rather than the ratings they should have been probably because
I forgot to tell him to recalculate everything. Now that you've pointed
it out to me, I've put the right ratings in the posted version.
http://members.lycos.co.uk/fiultra/t...17acircuit.jpg
Thanks for the heads-up. While we're here, we may as well discuss
resistors in secondaries, and dropping resistors in general.

I made the T68bis potato amp by stripping out a pair of 300B on a proto
and using my junkbox resistors to drop the voltages. When the little
amp goes out of the door or is stripped down, they go back in the
junkbox. My only concern at the time was that they were the right value
and overrated for the job.

NB: A 50W resistor doesn't dissipate 50W just because it is rated 50W.
The heat it dissipates is related to current flowing through it and the
resistance value. Colonel Ohm saves the day again:
P = I*I*R -- says nothing about the rating of the resistor which by
tradition is 2 or 3 times the dissipation arrived at for a safety
margin.

There are many reasons for using a resistor of the right value and a
higher rating.

1. You have it in junkbox already and don't need to wait for a delivery
from your component pusher.

2. The manufacturer doesn't make all the values in all the ratings, or
your supplier doesn't stock the full range, so you buy the value you
need in the next higher rating.

3. I like big chunky aliminium-cased resistors because they're
cool-running with all that area and fins besides.

4. In the case of at least one of the resistors you think over-rated,
the alternative was a nasty cement-cased pluggable resistor of the
right rating. I like neither the looks nor the sound of those.

5. The standard resistor I keep in all values and both the available
ratings is Kiwame. It gets a bit expensive sticking them in where they
won't make a difference to the sound.

6. I'm designing for DIYers. The great thing is not to give Joe Doe a
chance to say near enough is good enough and put an underrated part in.
Better safe than sorry.

7. Those particular resistors derate to 50 per cent (IIRC, look it up
if you don't know -- *that* is why I overrate them!) or less if they
aren't on a heatsink, if they aren't in free air, etc. What you see
isn't a 100W of power capability but only 50W inside a case, maybe
less. It is for tricky little subtleties like this that Patrick wants
people to hit the books rather than learn only by soldering.

8. It isn't so widely known that resistors have voltage ratings. It is
not uncommon, though less so these days of CE marks over here, to see
amps built with resistors that at least theoretically could burst into
flames any moment. Those ali-cased resistors I like have very
attractive voltage ratings too, so they live naturally in the junkbox
of someone who moves casually from a little 175V 417A potato amp to a
kilovolt-plus 845 or SV572.xx amp. The ali-cased resistors save the
bother of having to check the voltage spec of some orphan resistor from
the junkbox; I've long since cleared all the low-voltage stuff from my
junkbox.

****

Returning now to the particular resistors you mention, the two 330R in
the mains secondary are ballasts. In a tube rectifier circuit you're
supposed to have those, usually about 75R minimum. Check the spec
sheets for various tube rectifiers, on some of which is an explanation
and schematic of the equivalent circuit for various impedances in and
around a tube rectifier (for each type of filter, cap input and choke
input) and their effects.

I have long since found that a pair of stiff ballasts smooths the power
an agreeable fraction when you have a hefty bleed already.

*******

Remember this: the idea isn't a perfect schematic but to build
something, to listen, to develop it. I used to waste lots of time
agonising over the perfect paper design and collecting all the perfect
parts. Now as often as not I build the prototype on the fly with a few
calculations on the logarithmic bezels of my watch (why is a rotary
slide rule still called a "rule" -- tell me that and I'll think you
clever) to check my mental arithmetic, then develop it right, and only
then reverse engineer the amp to draw the schematic of the circuit.
There are a few traps in that, as we have seen, when sharp eyes catch
out your overrated junkbox parts but the amp gets done a lot sooner.

The secret of designing good-sounding amps and still have time left to
listen to music is to fail fast. Anyone who hasn't failed often, never
mind "never" as too many claim, probably can't distinguish mud from
music.

Andre Jute
Visit Jute on Amps at http://members.lycos.co.uk/fiultra/
"wonderfully well written and reasoned information
for the tube audio constructor"
John Broskie TubeCAD & GlassWare
"an unbelievably comprehensive web site
containing vital gems of wisdom"
Stuart Perry Hi-Fi News & Record Review


Surf my web pages at, http://users.rcn.com/jbyrns/

You thoroughly covered all the bases.

Come ON, John....

Show me any commercially-produced circuit with anything approaching
that much resistance (if any at all) on the B+ side _ahead_ of the
rectifier tube. And whilst you are at it, please explain the reasons
for all 660 ohms vs. a lower secondary voltage?

Or are your Master's nits not to be picked?

Peter Wieck
Wyncote, PA

Bunk! Your Pal, John Stewart

" said:


Two chokes? Why? The 5AR4 is a pretty good, quite rugged (if expensive)
rectifier. And it would seem simpler to add additional capacitance on
the line-side of the first choke, thereby eliminating the need for the
second?


The 5AR4/GZ 34 rectifier is available from Sovtek for about $10, at
least here in my neck of the woods.
I agree that's more expensive than 2 1N4007s, but on par with the 5U4G
you mention.
It has indeed the advantage of being indirectly heated, thereby
avoiding high surge peaks on the electrolytics.
A second advantage, often neglected, is that the 300B will only draw
current after the GZ rectifier is warm.
This is much better for the 300B cathode, the tube will last longer.
A third advantage, though of little use in this amplifier design, is
the lower voltage drop wrt. a directly heated rectifier such as the
5U4G.

André could try to use a swing choke at the cathode, this drops the
voltage a bit, but when calculated correctly, also provides a certain
voltage stability.
Although a SE amp is always biased in class A, small voltage
variations can not be avoided (depending on the load as well).

I myself would have selected a more suitable transformer, or a
combination of 2 or more, but apparently, André used what he had lying
around in his junkbox, hence the series and bleeder resistors.


I question from the perspective of one who is usually presented with
smoking ruins and given the mandate to 'make it work'. Many times
without benefit of schematics, or if they are available, facing so many
whimsical modifications to make the schematics of dubious value. So,
"expected" and "actual" values are important things to know. At times,
I thank my lucky stars that this is a hobby.... so I do not have to
make a living at it. Otherwise, not 1 unit in 10 that I see would be
worth the time and trouble to fix.


So true, I am familiar with this :-)

However, being both a repairman and an amp designer and builder, there
are differences in approaching both.

--

- Never argue with idiots, they drag you down their level and beat you with experience. -

André could try to use a swing choke at the cathode, this drops the voltage a bit, but when calculated correctly, also provides a certain voltage stability.

Actually, I would test a single diode on the secondary side of the B+,
to drop the voltage to ~353V+/- to the rectifier. Through the
rectifier, that would give a mere 292V *excepting resistors* on the
output side. This is a heatless solution with an open-circuit failure
mode. The question/test would be one of the downstream effect of
feeding chopped DC into the 5AR4. Worth a test to get to smaller
resistors anyway, and a way to reduce the load on the secondary coil
considerably. I am always loath to put dropping resistors (or
"ballasts" as so elegantly noted) on the secondaries, why load the poor
windings? If a suitable transformer were not available, I would drop on
the primary side as much as practical.

Peter Wieck
Wyncote, PA

" said:


Actually, I would test a single diode on the secondary side of the B+,
to drop the voltage to ~353V+/- to the rectifier. Through the
rectifier, that would give a mere 292V *excepting resistors* on the
output side. This is a heatless solution with an open-circuit failure
mode. The question/test would be one of the downstream effect of
feeding chopped DC into the 5AR4. Worth a test to get to smaller
resistors anyway, and a way to reduce the load on the secondary coil
considerably. I am always loath to put dropping resistors (or
"ballasts" as so elegantly noted) on the secondaries, why load the poor
windings? If a suitable transformer were not available, I would drop on
the primary side as much as practical.


While the resulting DC voltage will be lower in that case, the ripple
is certainly going to be far greater than in case of the dual-diode
power supply design.

Getting rid of ripple means big caps, pushing the average DC voltage
up again.

More ripple also means higher charge/discharge currents, which in turn
can cause hum induction in the actual amplifier circuit.

Dropping resistors don't load the windings, bleeders do.
A vacuum rectifier must see some DCR in the anode circuits, to prevent
cathode stripping.
A beefy tranny has a lower DCR, so series resistors *must* be added
to avoid large cathode peak currents caused by the electrolytics.

In case of a class A amplifier, burning some volts and watts away in
series resistors isn't a big sin IMHO, unless one is designing to
utmost efficiency.

Looking at the schematic again, I noticed that André actually uses the
Lundahl LL1638 choke as a swing choke.
As this choke wasn't designed as such, it won't regulate as good as a
correctly designed swing choke (without air gap).
It will provide some additional voltage drop and series resistance,
though.

--

- Never argue with idiots, they drag you down their level and beat you with experience. -

While the resulting DC voltage will be lower in that case, the ripple is certainly going to be far greater than in case of the dual-diode power supply design.

I think you misunderstand. The single diode is to drop the voltage
_into_ the 5AR4, thereby reducing the size needed for the dropping
resistors. The effective output ripple should be neither greater nor
worse than straight AC. So, 0.707 x input Voltage = output voltage from
the winding. A big drop, no heat generated and load still removed from
the winding.

Now, let me see if I understand you correctly. A bleeder resistor
dissipates a limited amount of current-to-ground, so the heat geneated
by the resistor will be a function of the available current, and a
dropping resistor dissiptates it in heat, but not to ground, so it
drops voltage but only wastes a limited amount of current? I understand
that would reduce the total load. But it would seem that eliminating
the need for 'ballasts' altogether would be far-and-away the better
approach.

Without getting cute about it, just keep in mind that this design is
being presented as the 'ultimate' in SET design, and as the ultimate in
simplicity. There is nothing whatsoever represented as 'junk-box' about
it, most especially as it is reputed to have significant value tied up
in two tubes alone. A 'magnum opus' if you will.

Now, with your observation on the two chokes, there seems much to
improve in this unit, starting with the iron itself. That the various
parts-and-pieces are carefully specified by-the-numbers and without the
qualifier "this is what was lying around" shows at least that much.

I would still like to understand the "expected" vs. "actual" voltages
so as to understand the function of the ballast resistors and how
precise they must be. And whether it would be practical to test other
expedients.

Ah, well. Salieri said of Mozart: Too many notes. Does "too many parts"
have the same ring?

Peter Wieck
Wyncote, PA

In article .com,
" wrote:

While the resulting DC voltage will be lower in that case, the ripple
is certainly going to be far greater than in case of the dual-diode power
supply design.

I think you misunderstand. The single diode is to drop the voltage
_into_ the 5AR4, thereby reducing the size needed for the dropping
resistors. The effective output ripple should be neither greater nor
worse than straight AC. So, 0.707 x input Voltage = output voltage from
the winding. A big drop, no heat generated and load still removed from
the winding.

Peter, I hate to be the one to have to tell you this but your slip is
showing. The above statement is utter nonsense, would you care to explain
it further?


Regards,

John Byrns


Surf my web pages at, http://users.rcn.com/jbyrns/

First, show me the nonsense. Expose and explain the nits.

Peter Wieck
Wyncote, PA

In article .com,
" wrote:

First, show me the nonsense. Expose and explain the nits.

Peter, there are no "nits" here, just massive "nonsense" on your part.

You made the following unsupported claim in a previous post:

"I think you misunderstand. The single diode is to drop the voltage _into_
the 5AR4, thereby reducing the size needed for the dropping resistors. The
effective output ripple should be neither greater nor worse than straight
AC. So, 0.707 x input Voltage = output voltage from the winding. A big
drop, no heat generated and load still removed from the winding."

Yet you refuse to explain exactly how and where you would connect the
"single diode" "_into_ the 5AR4" to produce this miraculous reduction of
the voltage by a factor of "0.707". With a few minor exceptions most of
us here are not mind readers, and we haven't a clue how you propose to
produce this result?

Face it Peter you are in way over your head with this, the air of
authority you traditionally try to cloak your pronouncements with just
won't cut it here, you must either back up your claims with some facts, or
accept that they are nonsense.


Regards,

John Byrns


Surf my web pages at, http://users.rcn.com/jbyrns/

John:

Take a simple diode capable of handling the 500V. Say.. 1N4007. Connect
it to one of the secondary winding leads. That will drop the voltage
across the winding from 500V to .707 x 500V. Feed that to the
rectifier. So, instead of windings-to-rectifier (assuming no dropping
resistors), now it is winding to diode to rectifier to winding. In only
_one_ of the two leads.

Or, do you not remember curtain-burner radios where this simple
expedient off the line-cord drops the 120V to about 84V or so?

Peter Wieck
Wyncote, PA

Peter:

It is quite clear to me that you are totally out of your depth here and
in your other posts in this thread. Here are just some samples:

1. You appear not to understand the rationale behind the various power
supply topologies and in particular how a choke input works or why it
is traditionally built with two sections, meaning two chokes.

2. As we saw earlier, you appear to think that a resistor will give off
heat exactly matching its power rating, which is totally untrue; the
heat dissipated is related to the resistance value, the current flowing
in the resistor, the mounting and the air flow over the resistor.

3. You appear not to understand, or to have overlooked despite being
told (if you do it again I will assume you are doing it maliciously and
react accordingly), the fact that the T68 was made from a 300B proto
merely to prove the driver stage of the KISS amp, and therefore uses
the 300B amp's power supply regardless of its precise suitability. It
is not presented as the ne plus ultra of anything. If you seriously
want to discuss power supply design, discuss the T39 circuit, also
published at the same time.
http://members.lycos.co.uk/fiultra/T...trafi-crct.jpg
Giving you the benefit of the doubt, I shall assume you're still
working your way down to. Work faster.

4. Your questions reveal that you do not to have the faintest idea of
the conventions guiding SE amp design towards the desired result.

In the light of these misunderstandings, and because I don't want to
repeat myself if and when we come to the T39
http://members.lycos.co.uk/fiultra/T...trafi-crct.jpg
my answers to the rest will be shorter than usual. (Hallelujah chorus
starts up!)

wrote:
It would be useful to know the secondary voltage at that transformer
before the resistors are added, so as to get the 180V rectified voltage
you require. Yes, you have 500V ~500ma at the bottom, I assume that is
across the entire two coils (5-to-7) and not to the (virtual)
center-tap, but that too would be helpful to know.

The convention is that a 250-0-250 transformer is described as 500Vct,
usually abbreviated on the schematic to 500V. The centre tap is not
virtual but real.

Assuming that you are getting 250V/Coil at your stated input, the way I
read your output from the rectifier tube, that would come to some 415V
or so out of the 5AR4/GZ34, excepting the dropping resistors. So, how
did the value of 660 ohms of total AC resistance get chosen, especially
in light of the 4700 ohm bleeder resistor further down the line (at 25
watts) to get to the required 180V?

It'll be in a chapter of the KISS files on my Fiultra site when I get
around to writing the chapter. Basically you decide the current
required by the tubes, allocate a bleed (which in the absence of a
swinging choke must be higher than a certain amount in a choke input
design -- not essential in my design with the 11 second delay on the
GZ34 filament but I always put in a hefty bleed for stability, safety
and just in case someone else plugs in an instantly-on rectifier), add
the two together, work back over the copper drop of the chokes,
transform the voltage and current via the rectifier tube backwards from
DC to AC, and then apply to Colonel Ohm for the value of the ballasts.

And 'adding a small capacitor' to
adjust voltage... this is an iffy (albeit nearly heatless) expedient,
'cause if that cap should fail, *poof*.

You do talk a lot of manure, Wiecky. The cap will have the same rating
as any of the other caps, just lower value. It is in the same position
as the cap in a proper cap input filter. There is no reason for it to
fail or precedence for it failing. (The idea of the voltage-tuning
small cap in front of a choke input filter was given to me by Gordon
Rankin, whose caps would *dare* fail...)

So, it would be useful to know
the required/expected voltages right down the line so that the correct
choices might be made.

They are written on my circuit, every single one of them. What are you
talking about? (We might note that I am one of the few designers who
write all the necessy information on the circuit.)

Would it not be much simpler to drop the primary side to ~220V or so,

No, no, no, never! Your winder will come cut you, pal.

thereby almost eliminating the need for filament-voltage dropping
resistors excepting getting 5V on the rectifier?

Peter, you have these resistors on the mind. The desire to eliminate
them arises from your ignorance about how much heat big resistors
radiate when only a little current flows, and cheap production
paradigms. In good audiophile tube design, and especially DIY work,
such resistors are treasured for the advantages they bring, which
Sander has tried to describe to you.

SWAG, assuming 230
single-phase hot/neutral at the primary, and about a 2A (allowing for
losses) total load shouldn't take much of a single dropping resistor to
get that 220V, or even slightly less. This way, individuals in other
countries with different standards could work to the required
_secondary_ voltages based on their wallplate voltage. If one is fond
of iron, either a small autotransformer or a small bucking transformer
could be used ILO a resistor for less heat.

No.

This might also greatly simplify the requirements for your B+ side?

Again, this is a temporary chassis for a proto for a part-amp. If you
want to discuss power supplies in terms of simplicity, look at the T39
design, which is the whole amp.
http://members.lycos.co.uk/fiultra/T...trafi-crct.jpg

Two chokes? Why?

Because that is how one builds a choke input supply. It cannot be
wound/specified/built more economically (Patrick?) or efficiently in
terms of smoothing than as two (equal) sections.

The 5AR4 is a pretty good, quite rugged (if expensive)
rectifier.

So what? I'm specifying a couple of grand's worth of tubes already.
Anyway, it sounds better than semiconductor diodes and lasts longer too
unless you heatsink diode bridges properly.

In the T39 the GZ34 will be replaced with a GZ37, which will really
hurt if you worry about costs!

And it would seem simpler to add additional capacitance on
the line-side of the first choke, thereby eliminating the need for the
second?

See above about efficiency and cost (cost at least in days of old --
maybe today a humongous choke could be cheaper).

Furthermore, the power supply is part of the transfer function. The
signal literally runs through it. In your mind's eye draw a line from
the bottom of the last filter cap on the T39
http://members.lycos.co.uk/fiultra/T...trafi-crct.jpg
to the ground of the RCA socket, and you will get the idea. In an SE
amp you want control over all the time constants, and therefore in the
power supply too. You can't just throw around extra capacitance without
considering the specification of available chokes, the time constants
you want further on, and so on, even onto your speakers (you can't
output too much below 32Hz in Lowthers, for instance, so you that is a
time constant in the 300B circuit which influences time constants all
the way back to the power supply). Again, this is an example of why
Patrick despairs of repair hacks who won't hit the RDH hard ever
learning anything really useful about tube amps. I mentioned Rankin
above for a purpose; he is a very thorough engineer and he says that
*after he had designed an amp* there were an additional 100 or so
checks he makes to be sure the thing will work right.

With all your prior losses, you are running well below the
saturation level of a single unit (400/575ma). 500V caps are cheap
these days, even 50uF or better, certainly cheaper than iron. And if
all you want to filter is 50/60Hz chop, one will do fine.

No, no, no! See above about time constants in the filters, efficiency
in the choke sections, etc. Then, as a practical matter, check a
catalogue for the physical size of the polyprop caps I have specified,
and you will be absolutely horrified at the floor space already on the
amp.

As a small
aside, the 5U4 rectifier is much cheaper, albeit not quite as rugged
and without the slow-start characteristics that distinguish the 5AR4.

I have a box full of 5U4 sitting three feet to my left as I write this.
If I wanted a 5U4, I would have specified and fitted it. Peter, put any
consideration of cost out of your mind unless and until *I* or another
*established* audiophile come to mention it; cost considerations
simply do not apply to DIY ultra-fi amps. The GZ34 is there because it
sounds right and, important this, to protect the 300B in DIY-built amps
with its slow-start filament. It is being replaced with GZ37, cost no
object, because that sounds better still.

But in any case, a single choke with sufficient capacitance would drop
any chop way below other noise sources.

No. RTRDH.

Are you familiar with Mad Man Muntz? He would go into his skunk-works
whenever his engineers decided they had a new product to develop, and
start cutting out parts (he was an excellent EE, so this was not done
at random) until whatever-it-was stopped working. *That* was the magic
point from which to design.

I question from the perspective of one who is usually presented with
smoking ruins and given the mandate to 'make it work'.

I have never had an amp fail to work on switch-on.

Many times
without benefit of schematics, or if they are available, facing so many
whimsical modifications to make the schematics of dubious value. So,
"expected" and "actual" values are important things to know.

The voltages and currents are on my circuit, together with the value
and rating of every other component, together with the maker's name of
every component, and in may cases the name of a supplier if the
component is rare. Again, you'd do better to study and discuss the T39
circuit.

At times,
I thank my lucky stars that this is a hobby.... so I do not have to
make a living at it. Otherwise, not 1 unit in 10 that I see would be
worth the time and trouble to fix.

I find it cheaper at the hourly rates my time is worth to design and
build a new amp rather than fix a broken one if much more than the fuse
is gone. It seems to me that amateur troubleshooting of high-voltage
devices is an ulcer-making pastime. Anyone who doesn't find it
ulcer-making lacks the imagination to be afraid of high voltage and
should find another hobby.

Peter Wieck
Wyncote, PA

Andre Jute
Visit Jute on Amps at http://members.lycos.co.uk/fiultra/
"wonderfully well written and reasoned information
for the tube audio constructor"
John Broskie TubeCAD & GlassWare
"an unbelievably comprehensive web site
containing vital gems of wisdom"
Stuart Perry Hi-Fi News & Record Review

Sander deWaal wrote:
" said:


Two chokes? Why? The 5AR4 is a pretty good, quite rugged (if expensive)
rectifier. And it would seem simpler to add additional capacitance on
the line-side of the first choke, thereby eliminating the need for the
second?


The 5AR4/GZ 34 rectifier is available from Sovtek for about $10, at
least here in my neck of the woods.
I agree that's more expensive than 2 1N4007s, but on par with the 5U4G
you mention.
It has indeed the advantage of being indirectly heated, thereby
avoiding high surge peaks on the electrolytics.
A second advantage, often neglected, is that the 300B will only draw
current after the GZ rectifier is warm.
This is much better for the 300B cathode, the tube will last longer.
A third advantage, though of little use in this amplifier design, is
the lower voltage drop wrt. a directly heated rectifier such as the
5U4G.

Those Mullard designed GZ types also sound pretty good.

André could try to use a swing choke at the cathode, this drops the
voltage a bit, but when calculated correctly, also provides a certain
voltage stability.

The point of a swinging choke is to provide a fractional delay while
capacitors charge up. The slow heater on the GZ34 already provides a
delay. Furthermore, a hefty bleed loads the choke even with an
instantly-on rectifier so that there is also an instant demand for
current. All these matters tend to reduce the need for a swinging
choke, which today is a very rare item.

Although a SE amp is always biased in class A, small voltage
variations can not be avoided (depending on the load as well).

Yes, that is indeed the great advantage of the choke input filter over
the cap input filter for SE amps where the demand is essentially
static.

I myself would have selected a more suitable transformer, or a
combination of 2 or more, but apparently, André used what he had lying
around in his junkbox, hence the series and bleeder resistors.

The T68, under discussion here, is a proto to prove the driving stage
of a bigger amp. I simply lost the two 300B and used what was on the
plate, adding droppers to make it work. It would be better, if Peter
really wants to learn something about SE power supply design, to
discuss the proper T39 amp he
http://members.lycos.co.uk/fiultra/T...trafi-crct.jpg

I question from the perspective of one who is usually presented with
smoking ruins and given the mandate to 'make it work'. Many times
without benefit of schematics, or if they are available, facing so many
whimsical modifications to make the schematics of dubious value. So,
"expected" and "actual" values are important things to know. At times,
I thank my lucky stars that this is a hobby.... so I do not have to
make a living at it. Otherwise, not 1 unit in 10 that I see would be
worth the time and trouble to fix.


So true, I am familiar with this :-)

However, being both a repairman and an amp designer and builder, there
are differences in approaching both.

Vast, apparently.

--

- Never argue with idiots, they drag you down their level and beat you with experience. -

Andre Jute
Visit Jute on Amps at http://members.lycos.co.uk/fiultra/
"wonderfully well written and reasoned information
for the tube audio constructor"
John Broskie TubeCAD & GlassWare
"an unbelievably comprehensive web site
containing vital gems of wisdom"
Stuart Perry Hi-Fi News & Record Review

wrote:
While the resulting DC voltage will be lower in that case, the ripple is certainly going to be far greater than in case of the dual-diode power supply design.

I think you misunderstand. The single diode is to drop the voltage
_into_ the 5AR4, thereby reducing the size needed for the dropping
resistors. The effective output ripple should be neither greater nor
worse than straight AC. So, 0.707 x input Voltage = output voltage from
the winding. A big drop, no heat generated and load still removed from
the winding.

Forget it. You will hear that diode. I go to very great trouble to keep
all kinds of clicks and whirs out of the amp, and now you want me to
add a diode across one winding? Yech! To avoid resistors demanded by
the rectifier? Why? You want to go to Philly from Alston, you don't
first go to Santa Barbara.

Now, let me see if I understand you correctly. A bleeder resistor
dissipates a limited amount of current-to-ground, so the heat geneated
by the resistor will be a function of the available current, and a
dropping resistor dissiptates it in heat, but not to ground, so it
drops voltage but only wastes a limited amount of current? I understand
that would reduce the total load. But it would seem that eliminating
the need for 'ballasts' altogether would be far-and-away the better
approach.

Without getting cute about it, just keep in mind that this design is
being presented as the 'ultimate' in SET design,

Who says that? It has been repeatedly clearly described as prototype to
prove the driver stage of another amp. It is described as a "prototype"
on the circuit. You are confusing a proving proto with the proper
design which is he
http://members.lycos.co.uk/fiultra/T...trafi-crct.jpg

and as the ultimate in
simplicity.

Sure thing, the earlier T68 with a dedicated power supply was designed
and built to beat the parts count of the Gaincard.

There is nothing whatsoever represented as 'junk-box' about
it, most especially as it is reputed to have significant value tied up
in two tubes alone. A 'magnum opus' if you will.

A trial run of a part of a magnum opus.

Now, with your observation on the two chokes, there seems much to
improve in this unit, starting with the iron itself.

Holy Moses! Wiecky, you are talking through the back of your neck. You
never heard of swing chokes until today, and five minutes later you
want to teach me power supply design. Go read the RDH before you
embarrass yourself some more.

That the various
parts-and-pieces are carefully specified by-the-numbers and without the
qualifier "this is what was lying around" shows at least that much.

These prissy-mouthed judgemental statements of yours irritates people
who can see plainly that you are a newby and none too quick a newbie
either. None of us have a lot of patience with idiots. This is your
second chance and your wasting it in pretence that you know better than
I do.

I would still like to understand the "expected" vs. "actual" voltages
so as to understand the function of the ballast resistors and how
precise they must be. And whether it would be practical to test other
expedients.

Build your own and listen to it. It is always practical to test other
expedients. I did, and I ****ed people off going on about those dumb
ideas, just as you do now. But hey, maybe you learn something new. I
did, that business about the harmonic distribution of the remnant of
distortion.

Ah, well. Salieri said of Mozart: Too many notes. Does "too many parts"
have the same ring?

Well, if you got off your arse and found the right circuit, rather than
some part-proto, we could discuss parts count. Try he
http://members.lycos.co.uk/fiultra/T...trafi-crct.jpg

Peter Wieck
Wyncote, PA

wrote:
John:

Take a simple diode capable of handling the 500V. Say.. 1N4007. Connect
it to one of the secondary winding leads. That will drop the voltage
across the winding from 500V to .707 x 500V. Feed that to the
rectifier. So, instead of windings-to-rectifier (assuming no dropping
resistors), now it is winding to diode to rectifier to winding. In only
_one_ of the two leads.

Or, do you not remember curtain-burner radios where this simple
expedient off the line-cord drops the 120V to about 84V or so?

I'm not building a radio, I have no desire burn curtains. I think you
have yourself given the reason for not using this silly diode idea,
which has absolutely no place in a hi-fi amp.

Peter Wieck
Wyncote, PA

I meant Wyncote of course when I wrote Alston elsewhere in this thread.

You're still wasting time on a proving proto cut out of a bigger proto
and made to work by dropping resistors. This is *mindless* attention to
the least relevant and most temporary part of a temporary circuit. I
suggest we leave it there.

The real circuit is
hehttp://members.lycos.co.uk/fiultra/T...trafi-crct.jpg

Andre Jute
Visit Jute on Amps at http://members.lycos.co.uk/fiultra/
"wonderfully well written and reasoned information
for the tube audio constructor"
John Broskie TubeCAD & GlassWare
"an unbelievably comprehensive web site
containing vital gems of wisdom"
Stuart Perry Hi-Fi News & Record Review

In article .com,
" wrote:

John:

Take a simple diode capable of handling the 500V. Say.. 1N4007. Connect
it to one of the secondary winding leads. That will drop the voltage
across the winding from 500V to .707 x 500V. Feed that to the
rectifier. So, instead of windings-to-rectifier (assuming no dropping
resistors), now it is winding to diode to rectifier to winding. In only
_one_ of the two leads.

OK, so we connect a 1N4007 diode between one of the transformer secondary
leads and the corresponding anode of the 5AR4 rectifier tube, have I got
it right so far? Which way around do we connect the 1N4007 diode? What
do we do with the other end of the CT HV winding, do we leave it connected
to the other anode of the 5AR4, or do we disconnect it, or what?

Or, do you not remember curtain-burner radios where this simple
expedient off the line-cord drops the 120V to about 84V or so?

We are not talking about a "curtain-burner radio" here, we are talking
about a sophisticated ultra fidelity amplifier! What you say is true of
the heater string in a "curtain-burner radio" when feed from an AC sine
wave power source, but it is not true of the B+ supply. If you put a
silicon diode in series with the AC feed to the anode of the rectifier
tube, it will either have virtually no effect on the B+ voltage, or it
will reduce the B+ voltage to zero, depending on the orientation of the
added diode.

In the heater circuit of a "curtain-burner radio" it is the RMS value of
the voltage that counts, while in the B+ rectifier it is either the peak
value, or the average value of the voltage that counts, depending on the
type of filter circuit used with the rectifier. The diode has different
effects on each of these values, hence you can't apply your
"curtain-burner radio" knowledge to the B+ supply of a sophisticated
audiophile amplifier like this.


Regards,

John Byrns


Surf my web pages at, http://users.rcn.com/jbyrns/

Sander deWaal wrote:
" said:

[silly bit of transformerless table radio gimmickry about silicon
diodes on one winding snipped]
If a suitable transformer were not available, I would
[another silly idea snipped]

Even a blind squirrel must find a nut occasionally. I looked up the
chicken scrawl on the clipboard from my workbench. I used a
250-0-250Vac secondary transformer with 330 ohms of ballast in each
leg. According to my notes the alternatives we

a) special-order a proper power tranny 240-0-240. Gee, just 10 volt
difference?

b) use the tranny already on the chassis and drop c110mA in the
bleeder; this lets you use the GZ34 with a standard spec sheet 100 ohms
of ballast in each leg.

c) use the tranny already on the chassis and boost the ballast
resistors to finetune the voltage, as the makers of the GZ34 clearly
intended you to do because they limited the capacitance you may use.

Of course I went for option c! Those ballast resistor are supposed to
be there, regardless of how they bother Peter Wieck.

Sorry, Peter, the other blind squirrel got the nut.

While the resulting DC voltage will be lower in that case, the ripple
is certainly going to be far greater than in case of the dual-diode
power supply design.

Getting rid of ripple means big caps, pushing the average DC voltage
up again.

More ripple also means higher charge/discharge currents, which in turn
can cause hum induction in the actual amplifier circuit.

Dropping resistors don't load the windings, bleeders do.
A vacuum rectifier must see some DCR in the anode circuits, to prevent
cathode stripping.
A beefy tranny has a lower DCR, so series resistors *must* be added
to avoid large cathode peak currents caused by the electrolytics.

In case of a class A amplifier, burning some volts and watts away in
series resistors isn't a big sin IMHO, unless one is designing to
utmost efficiency.

A fellow of Scottish extraction owned one of my favourite small tube
manufactories. He delivers a set of transformers to me, of which he
says he has plenty on his shelves. I am to design an amplifier using
these transformers. He also gives me one unit of the amp currently
built with them and says I must use the stainless steel topplate from
that. So I reverse engineer this existing amp and discover that the
other designer (a much-respected Englishman) ran the poor power supply
tranny to within 1mA of total rated capacity. This is clearly a
monstrous miscalculation but I can't find out where I went wrong, so I
call the tranny designer and say to him, "According to my calculations,
this tranny is stressed out to within a milliamp of its life." And the
tranny designer says, "Don't tell Mr X! He will make you design for the
last milliamp as well! And don't put the amount of current you want to
bleed on circuit or he'll try to bargain you down!"

Peter must have learned that sort of "production economy" somewhere and
had it impressed on him for life in order for him at this stage of his
life, in ultra-fi amps at that, to be so worried about 10 volts and
possibly three or four buck wasted in over-rated resistors -- on a
disposable part-prototype to prove a sub-assembly!

Looking at the schematic again, I noticed that André actually uses the
Lundahl LL1638 choke as a swing choke.
As this choke wasn't designed as such, it won't regulate as good as a
correctly designed swing choke (without air gap).
It will provide some additional voltage drop and series resistance,
though.

I've answered this in my first reply to this letter but there is an
additional fine point about the chokes that is easily overlooked unless
you already know about the trick. It is mounting a split choke with two
coils on common iron to straddle both voltage rails; this is a super
means of achieving that extra edge of common mode rejection that in the
long run will make the amp so much more satisfying that it is worth any
amount of money for chokes with this capability.

--
- Never argue with idiots, they drag you down their level and beat you with experience. -

I dunno. I would never have discovered half this stuff if I weren't an
idiot who would ask any question and not care if the clowns sneered and
jeered as long as someone gave me the answer.

Andre Jute
Visit Jute on Amps at http://members.lycos.co.uk/fiultra/
"wonderfully well written and reasoned information
for the tube audio constructor"
John Broskie TubeCAD & GlassWare
"an unbelievably comprehensive web site
containing vital gems of wisdom"
Stuart Perry Hi-Fi News & Record Review

wrote in message
oups.com...

Ah, well. Salieri said of Mozart: Too many notes. Does "too many parts"
have the same ring?

Mozart performed a "medley" of the highlights of Salieri's life's work,
It lasted just under two minutes:-)

Iain

" wrote:

Why do you still have some 100 watts of dropping resistors on the
secondary side of the transformer?

http://members.lycos.co.uk/fiultra/t...17acircuit.jpg

Peter Wieck
Wyncote, PA

I cannot see any 100watt dropping resistors anywhere.
Do you mean the 2 x 100 ohm to ground the 417 heaters?

Which transformer do you mean? output or power?

Patrick Turner.

Mr. McCoy changed them.... As _specified_ originally, there was over
100 watts of dropping resistors.

Peter Wieck
Wyncote, PA

Mozart performed a "medley" of the highlights of Salieri's life's work, It lasted just under two minutes:-)

That long?

This entire saga reminds me of the Parable of the Elephants and their
Child. Much trumpeting, alarums & diversions at the conception, but no
results for some two years thereafter. It does seem that Mr. McCoy does
want it both ways. He should be massively grateful to Mr. Byrns for
keeping him out of serious trouble and telling the rest of the world
what he really means. But, the elephants are looking like mayflies as
against the time this "perfect" amp is taking.

Peter Wieck
Wyncote, PA

John:

OK. So, what you are writing is that clipping off half the sine wave
will have no effect on the secondary voltage, or it will drop it to
zero, depending on the orientation of the diode? This due to the nature
of the rectifier used?

And apart from that, have you found an application other than the one
in question where such 'ballast' resistors are used? That is, apart
from home-brew necessities adapting not-quite-suited parts to a
particular purpose?

Careful about using the word "sophisticated" in this application.

Function: adjective
Etymology: Medieval Latin sophisticatus
1 : not in a natural, pure, or original state : ADULTERATED a
sophisticated oil
2 : deprived of native or original simplicity: as a : highly
complicated or developed : COMPLEX sophisticated electronic devices b
: having a refined knowledge of the ways of the world cultivated
especially through wide experience a sophisticated lady
3 : devoid of grossness: as a : finely experienced and aware a
sophisticated columnist b : intellectually appealing a sophisticated
novel

One has to go pretty far down for a positive definition, and as the
goal is KISS, even that seems in direct conflict with the stated goal
in any case.

Peter Wieck
Wyncote, PA

wrote in message
oups.com...
Mozart performed a "medley" of the highlights of Salieri's life's work,
It lasted just under two minutes:-)

That long?

Do you know the extent of Salieri's output?
Mozart probably played at tempo "Largo" :-)


Iain

wrote in message
ups.com...
As I remember, his output was largely equivalent to Mr. McCoy's. Much
fuss, pomp and pretence, little substance.



Salieri was acctually quite a good composer. It was
unfortunate for him that he had to be born in the same
era as W.A.M.

Bing Crosby said of Frank Sinatra. "His is a talent
one meets only once in a lifetime. Why did it have
to be in mine?"

One of my favourite 20th century composers,
Einar Englund, suffered the same misfortune, and
lived constantly in the shadow of Jean Sibelius.

Iain

Salieri suffered much as Moltor (Bach then Hayden), Gluck (more-or-less
similarly) and quite a few others being in the shadow of the 'greats'.
He was, as you say, a fair composer, but much of what he did suffered
by being tight-to-formula. Apart from the Movie and Play, historically,
his objections to Mozart were that he was not so formulaic, and as a
rebel a direct threat to his position. Almost the same (musical-only)
comparison as Telemann to Vivaldi. Telemann was a competent composer,
wrote some great stuff, but as compared to Vivaldi, he is a little bit
elephantine.

Moltor and Gluck, now... there are some wonderful pieces by these two.
I use the Moltor Trumpet concerto as a check-piece quite often. Gluck
is an acquired taste, but stunning.

Peter Wieck
Wyncote, PA

wrote in message
oups.com...
Salieri suffered much as Moltor (Bach then Hayden), Gluck (more-or-less
similarly) and quite a few others being in the shadow of the 'greats'.
He was, as you say, a fair composer, but much of what he did suffered
by being tight-to-formula. Apart from the Movie and Play, historically,
his objections to Mozart were that he was not so formulaic, and as a
rebel a direct threat to his position. Almost the same (musical-only)
comparison as Telemann to Vivaldi. Telemann was a competent composer,
wrote some great stuff, but as compared to Vivaldi, he is a little bit
elephantine.

Moltor and Gluck, now... there are some wonderful pieces by these two.
I use the Moltor Trumpet concerto as a check-piece quite often. Gluck
is an acquired taste, but stunning.

Peter Wieck
Wyncote, PA


Hello Peter. Nice to discuss music with you.

Just been looking through some catalogues. Considering his repertoire,
Salieri is not well represented. As regards being tight to formula, one
could accuse Haydn and also perhaps Mozart of the same thing.

Personally, I find the genius of Mozart overwhelming.
It is funny how composers become known for their "potboilers"
I recently worked on a corporate film where the client had gone to great
expense to clear copyright for the use of Sibelius:Karelia Suite.
At a production meeting, we were talking about the music edit,
and how and where this incredibly wonderful (and very expensive)
music could be used. The client said "We only need about forty seconds.
Cut all the the best bits together!"

I very much enjoy Telemann - good solid technique. Vivaldi is best known
for some of his less-good works (Four Seasons) For me, the Concerto
for two Oboes, Bassoon, Two Horns and Violin (Fmaj RV574) is a
much more interesting work (but maybe lacking the catchy melodies)

There are also some very interesting little known European composers
particularly of the Baroque era. One of my favourites is the Dutrchman
Willem Fesch. (my music tutor calls him Handel in clogs!!)

Neither Moltor nor Gluck have really fired my imagination. But now
you have kindled a spark........:-)

I find I may spend weeks listening to baroque works, and then suddenly
switch to Charles Ives, or Ellington or Thomas Arne.

So much music, so little time:-)

Iain

Vivaldi Mandolin
Moltor Trumpet

Nice transition from Mozart to Beethoven and beyond: Johann Nepomuk
Hummel, with specific reference to his Mandolin and Trumpet works.

Done right and at a resonable volume, a test of any system.

Ellington, definitely. Ives, at the right time and mood. Arne, I have
not acquired that taste, but neither have I rejected it...

So much great music, so little time.

Peter Wieck
Wyncote, PA

On 31 Mar 2006 11:32:10 -0800, " wrote:

Vivaldi Mandolin
Moltor Trumpet

Nice transition from Mozart to Beethoven and beyond: Johann Nepomuk
Hummel, with specific reference to his Mandolin and Trumpet works.

Done right and at a resonable volume, a test of any system.

Ellington, definitely. Ives, at the right time and mood. Arne, I have
not acquired that taste, but neither have I rejected it...

So much great music, so little time.

Peter Wieck
Wyncote, PA

All great music, I'm sure - but I wouldn't use any of those to test a
system; they are far too musically dense. They are really hard to hear
past to see what the system is like.

For system testing I use speech, from friends - both male and female.
That is a really severe test, and very few systems actually sound like
my friends.

For musical testing I favour Bartok quartets - get a nicely staged
recording and you will find both physical and tonal space between all
the instruments that will reveal the actual quality of the system.

d

Pearce Consulting
http://www.pearce.uk.com

I do happen to have the "Bartok Quartet" recordings of Beethoven's
string quartets. Sadly, it is a marginal recording technically and not
a fair test of any system. Not the same thing, for sure but you
triggered a memory.

As my primary test pieces, I use a Kiri Te Kanawa recording of various
classical and baroque pieces giving a good deal of solo soprano voice.
She has a lot of color in her voice, more-so than most sopranos and can
reach well down into the contralto-range. Done right, she is 'right
there' and breathing. Done wrong and I picture her on a stage about
fifty feet away.

Also solo trumpet and solo harpsichord. I am overly fond of baroque
trumpet.

For full-range, the Saint-Saens Organ Symphony will reach well down
into the nether regions, yet demand clarity up top. If the systems pass
the above test, then I trot out this last. If I can pick out the
parts-and-sections of the orchestra, great. If I hear lots of mud,
not-so-great.

Peter Wieck
Wyncote, PA

On 31 Mar 2006 12:06:03 -0800, " wrote:

I do happen to have the "Bartok Quartet" recordings of Beethoven's
string quartets. Sadly, it is a marginal recording technically and not
a fair test of any system. Not the same thing, for sure but you
triggered a memory.

Well, it does have to be a super-nice recording.

As my primary test pieces, I use a Kiri Te Kanawa recording of various
classical and baroque pieces giving a good deal of solo soprano voice.
She has a lot of color in her voice, more-so than most sopranos and can
reach well down into the contralto-range. Done right, she is 'right
there' and breathing. Done wrong and I picture her on a stage about
fifty feet away.

I find Kiri a bit affected in her vowel sounds - very hard to
establish what is "right" from her voice, I find. Got any old Emma
Kirkby?

Also solo trumpet and solo harpsichord. I am overly fond of baroque
trumpet.

For full-range, the Saint-Saens Organ Symphony will reach well down
into the nether regions, yet demand clarity up top. If the systems pass
the above test, then I trot out this last. If I can pick out the
parts-and-sections of the orchestra, great. If I hear lots of mud,
not-so-great.

That will do nicely.

d

Pearce Consulting
http://www.pearce.uk.com

Iain Churches wrote:
Gluck
Iain

Glug, glug.

Way my disc storage system works, with about 250-300 catalogue entries
(more discs, of course, as many are in sets) per box, with the boxes
stacked on top of each other, it is a pain to move up and down the
alphabet by restacking heavy boxes, so I'm still in the Gs, where I
went looking for Gregorian Chant a while ago when we last discussed
point source drivers, horns, etc.

It must be serendipity that I'm playing Gluck as I read your post, at
present Gardiner's Iphigenie en Aulide, from a box set which also
includes Don Juan and Les Pelerins de la Mecque (and, to fill out the
box, I suppose, Scubert Ss 8 & 9). Next Orphee et Eurydicee with Dawn
Upshaw, the SF version under Runnicles. That should be enough Gluck to
keep me honest for a few years of gorgin on Handel...

For some totally subliminal reason, something in Gluck has reminded me
of the moment in Schutz's Christmas Story where the countertenor comes
in, a startling moment in one of my two recordings of the composition
and yet not in the other, so I'll be in the S boxes next... I can't
remember which is the startling recording, the Oxford Camerata/Naxos or
the King's Consort/Hyperion version, so I'll just play them both for
double the pleasure.

Andre Jute
Logical progressions are so predictable

Patrick Turner wrote:
" wrote:

Why do you still have some 100 watts of dropping resistors on the
secondary side of the transformer?

http://members.lycos.co.uk/fiultra/t...17acircuit.jpg

Peter Wieck
Wyncote, PA

I cannot see any 100watt dropping resistors anywhere.
Do you mean the 2 x 100 ohm to ground the 417 heaters?

Which transformer do you mean? output or power?

Patrick Turner.

Witless Wiecky is looking at the circuit of a different amp, on an
already replaced version of the schematic -- but there aren't any 100W
resistors on there either.

Poor Witless thinks that if one uses a 50W resistor it will give off
50W of heat, regardless of how much current flows in it. It really is
frustrating trying to help him. Sander and John and I tried to explain
to him why:

1. Why one shouldn't use halfwave rectification.

2. Why a bleed resistor (he counts the bleeder in his list of "unwanted
heat dissipators") is necessary.

3. Why a stiff bleed stabilizes the power delivery.

4. Why ballasts are in the secondary legs of the power transformer.

5. Why one doesn't lower voltage by inserting resistors into the
primary.

6. Why choke input power filters are made with two sections.

Etcetera, a very, very long list of things we take for granted that I
was amazed to discover even a repair hack doesn't know, and especially
a repair hack like Witless, who has the presumption to lecture us.

I have concluded that Witless Wiecky is obdurately and permanently
ignorant and a waste of my time. I've already put him back in my
killfile.

I really can't understand the sort of person who arrives on RAT without
any visible achievement --and starts telling the doers how they should
do a job they have been doing well for years. Doesn't it occur to
clowns like Witless Wiecky that they should read Morgan Jones and at
least a few relevant chapters of the RDH before they start preaching to
someone who has been designing amps for fifteen years? As far as I can
make out, Witless doesn't know the most basic things about electricity
or amplifers. Even as a repair hack his knowledge must be suspect if
he doesn't even understand the difference between DC and AC, which is
the implication of his suggestion of a diode on only one winding of a
power transformer secondary and the subsequent horrifying exchange with
John Byrns. The people who let Wiecky "clean" (his word; one presumes
he didn't attempt repair) their Conrad Johnson amps are either rich
enough to afford a new one when he wrecks it or reckless with their
property. Witless must be a danger to himself too; ignorance and high
voltage are fatal neighbours.

Andre Jute

"Andre Jute" wrote in message
ups.com...

Patrick Turner wrote:
" wrote:

Why do you still have some 100 watts of dropping resistors on the
secondary side of the transformer?

http://members.lycos.co.uk/fiultra/t...17acircuit.jpg

Peter Wieck
Wyncote, PA

I cannot see any 100watt dropping resistors anywhere.
Do you mean the 2 x 100 ohm to ground the 417 heaters?

Which transformer do you mean? output or power?

Patrick Turner.

Witless Wiecky is looking at the circuit of a different amp, on an
already replaced version of the schematic -- but there aren't any 100W
resistors on there either.

Poor Witless thinks that if one uses a 50W resistor it will give off
50W of heat, regardless of how much current flows in it. It really is
frustrating trying to help him. Sander and John and I tried to explain
to him why:

1. Why one shouldn't use halfwave rectification.

2. Why a bleed resistor (he counts the bleeder in his list of "unwanted
heat dissipators") is necessary.

3. Why a stiff bleed stabilizes the power delivery.

4. Why ballasts are in the secondary legs of the power transformer.

5. Why one doesn't lower voltage by inserting resistors into the
primary.

6. Why choke input power filters are made with two sections.

Etcetera, a very, very long list of things we take for granted that I
was amazed to discover even a repair hack doesn't know, and especially
a repair hack like Witless, who has the presumption to lecture us.

I have concluded that Witless Wiecky is obdurately and permanently
ignorant and a waste of my time. I've already put him back in my
killfile.

I really can't understand the sort of person who arrives on RAT without
any visible achievement --and starts telling the doers how they should
do a job they have been doing well for years. Doesn't it occur to
clowns like Witless Wiecky that they should read Morgan Jones and at
least a few relevant chapters of the RDH before they start preaching to
someone who has been designing amps for fifteen years? As far as I can
make out, Witless doesn't know the most basic things about electricity
or amplifers. Even as a repair hack his knowledge must be suspect if
he doesn't even understand the difference between DC and AC, which is
the implication of his suggestion of a diode on only one winding of a
power transformer secondary and the subsequent horrifying exchange with
John Byrns. The people who let Wiecky "clean" (his word; one presumes
he didn't attempt repair) their Conrad Johnson amps are either rich
enough to afford a new one when he wrecks it or reckless with their
property. Witless must be a danger to himself too; ignorance and high
voltage are fatal neighbours.

Andre Jute


Yep, could be.
OR maybe, just maybe,
Peter is just pulling your leg.
Heh Heh!
If he is, then these, and his other posts, rate as a fairly brilliant piece
of usenet hijinx.
Peter has kept you and others quite busy lately. Chasing your tails maybe?
I, myself, don't really care. Try it out, you might live longer with less
stress.
Unless you happen to trive on Bull****; I suspect a few do.
It's a beautiful spring evening in Flemington; windows open ect. and the
I've
just cracked my first of a few (maybe more!) Yuenglings. 90.1 is on the box
and sounds pretty good right now. Eyeing, though, some vinyl I've haven't
heard in awhile.
M

MarkS wrote:
"Andre Jute" wrote in message
ups.com...

Patrick Turner wrote:
" wrote:

Why do you still have some 100 watts of dropping resistors on the
secondary side of the transformer?

http://members.lycos.co.uk/fiultra/t...17acircuit.jpg

Peter Wieck
Wyncote, PA

I cannot see any 100watt dropping resistors anywhere.
Do you mean the 2 x 100 ohm to ground the 417 heaters?

Which transformer do you mean? output or power?

Patrick Turner.

Witless Wiecky is looking at the circuit of a different amp, on an
already replaced version of the schematic -- but there aren't any 100W
resistors on there either.

Poor Witless thinks that if one uses a 50W resistor it will give off
50W of heat, regardless of how much current flows in it. It really is
frustrating trying to help him. Sander and John and I tried to explain
to him why:

1. Why one shouldn't use halfwave rectification.

2. Why a bleed resistor (he counts the bleeder in his list of "unwanted
heat dissipators") is necessary.

3. Why a stiff bleed stabilizes the power delivery.

4. Why ballasts are in the secondary legs of the power transformer.

5. Why one doesn't lower voltage by inserting resistors into the
primary.

6. Why choke input power filters are made with two sections.

Etcetera, a very, very long list of things we take for granted that I
was amazed to discover even a repair hack doesn't know, and especially
a repair hack like Witless, who has the presumption to lecture us.

I have concluded that Witless Wiecky is obdurately and permanently
ignorant and a waste of my time. I've already put him back in my
killfile.

I really can't understand the sort of person who arrives on RAT without
any visible achievement --and starts telling the doers how they should
do a job they have been doing well for years. Doesn't it occur to
clowns like Witless Wiecky that they should read Morgan Jones and at
least a few relevant chapters of the RDH before they start preaching to
someone who has been designing amps for fifteen years? As far as I can
make out, Witless doesn't know the most basic things about electricity
or amplifers. Even as a repair hack his knowledge must be suspect if
he doesn't even understand the difference between DC and AC, which is
the implication of his suggestion of a diode on only one winding of a
power transformer secondary and the subsequent horrifying exchange with
John Byrns. The people who let Wiecky "clean" (his word; one presumes
he didn't attempt repair) their Conrad Johnson amps are either rich
enough to afford a new one when he wrecks it or reckless with their
property. Witless must be a danger to himself too; ignorance and high
voltage are fatal neighbours.

Andre Jute


Yep, could be.
OR maybe, just maybe,
Peter is just pulling your leg.
Heh Heh!
If he is, then these, and his other posts, rate as a fairly brilliant piece
of usenet hijinx.
Peter has kept you and others quite busy lately. Chasing your tails maybe?

Scary thought, that, MarkS. But, nah, I used to work in the theatre and
in films and I still do the odd thing in television, and nobody is an
actor so good he can deliberately look as stupid as Witless Wiecky
does, nor for as long as Witless Wiecky has looked so convincingly
stupid.

I, myself, don't really care. Try it out, you might live longer with less
stress.
Unless you happen to trive on Bull****; I suspect a few do.
It's a beautiful spring evening in Flemington; windows open ect. and the
I've
just cracked my first of a few (maybe more!) Yuenglings. 90.1 is on the box
and sounds pretty good right now. Eyeing, though, some vinyl I've haven't
heard in awhile.

Yeah. I have some Fats Domino on LP that I don't have on CD. But it is
such a bother unpacking and setting up a turntable...

Andre Jute

M