** Where is Pat Turner ????

Has he got his head buried in the sand or is it permanently up his own
backside ????

The posturing old fart posted this piece of crazy crap a few days back and
all his loyal arselickers ate it up !!!

" Transistor amps typically have an open loop response curve that looks like
an arch, with a peak at 500 Hz, and rolling off
at 6 dB/octave either side. "


Does NOBODY here have a clue how a SS amp actually works ????

Does NOBODY know that a SS amps has full its open loop gain down to DC ????

Does NOBODY dare challenge any of the excreta dropped from Turner the
Turd's bum on the world ????


His considered "New cathode bias method" cannot work as claimed
ither - that 1000uF will still charge up significantly on a steady drive
signal while the transistor does SFA about it.

Seems Pat Turner is not the ONLY stupid damn ostrich round here - the
place is overrun by them




........... Phil

"Phil Allison" wrote in message
u...


seems that we all are too tired with crap.
get a life-this is only ****in' internet.
you are just boring and Pat Turner is also boring with his serious
considering what Prick and Psychotic Midget have to say.

--
--
.................................................. ........................
Choky
Prodanovic Aleksandar
YU

"don't use force, "don't use force,
use a larger hammer" use a larger tube
- Choky and IST"
- ZM
.................................................. ...........................

" Transistor amps typically have an open loop response curve that looks like
an arch, with a peak at 500 Hz, and rolling off
at 6 dB/octave either side. "


Does NOBODY here have a clue how a SS amp actually works ????

Does NOBODY know that a SS amps has full its open loop gain down to DC ????



I was puzzled by the above "looks like an arch" statement. Modern power
transistors are capable of
doing several MHz frequency response, and the signal level ones can
operate up into the VHF
range. And all can do DC. So, what a SS amp can do would be dictated
by the other
parts in the amp. Now, if one has a few slow op-amps in that SS amp,
and some relatively small
coupling caps, then maybe the open loop gain might look like that arch.
It depends on
the design of the SS amp as to if it can do DC or if it ends up looking
like an arch. Same thing
with tubes. There the coupling caps, transformers and such dictate the
response. Though DC
coupling with a tube amp is rather difficult, as there are no
complements to electron tubes.

"Robert Casey"

" Transistor amps typically have an open loop response curve that looks like
an arch, with a peak at 500 Hz, and rolling off
at 6 dB/octave either side. "

Now, if one has a few slow op-amps in that SS amp, and some relatively
small coupling caps, then maybe the open loop gain might look like that
arch.


** What SS power amps have coupling caps INSIDE the NFB loop ????

NONE !!!!


It depends on the design of the SS amp as to if it can do DC or if it
ends up looking
like an arch.


** Virtually all SS amps are direct coupled internally - ie they have full
open loop gain at DC.

A few rare beasts exist with driver transformers - but even they
operate flat down to a few Hz.



Same thing with tubes.


** So you see direct coupled, transformerless tubes amps all over the place
???

These would be the only equivalents of SS amps.

Get real dickhead.

Turner the Turd posted a really stupid technical error (one of a great
many) and will not look at it.




............. Phil

Phil Allison wrote:

"Robert Casey"

" Transistor amps typically have an open loop response curve that looks like
an arch, with a peak at 500 Hz, and rolling off
at 6 dB/octave either side. "



Now, if one has a few slow op-amps in that SS amp, and some relatively


small coupling caps, then maybe the open loop gain might look like that
arch.


** What SS power amps have coupling caps INSIDE the NFB loop ????

NONE !!!!


Well, I was thinking of some old SS amps I had. Stuff dating back to
the early seventies.
Prehaps no modern SS amp has any coupling caps inside the NFB loop...




It depends on the design of the SS amp as to if it can do DC or if it


ends up looking


like an arch.




** Virtually all SS amps are direct coupled internally - ie they have full
open loop gain at DC.

A few rare beasts exist with driver transformers - but even they
operate flat down to a few Hz.





Same thing with tubes.




** So you see direct coupled, transformerless tubes amps all over the place


Well, there are OTL amps, but for the most part direct coupled tube amps
are rather difficult
and ackward to do. If you want any voltage gain....

My point was that, aside from some Miller effect issues with triodes,
tubes are not
the limiting factor for frequency response in the audio spectrum. It
takes only a few
nanoseconds for electrons to go from the cathode to the plate. Stray
capacitences
and Miller effect are what limit frequency response. T=RC....

"Robert Casey"

** You again snipped out the context so I am putting it back !!!

"Transistor amps typically have an open loop response curve that looks like
an arch, with a peak at 500 Hz, and rolling off
at 6 dB/octave either side. "


Phil Allison wrote:
** What SS power amps have coupling caps INSIDE the NFB loop ????

NONE !!!!

Well, I was thinking of some old SS amps I had. Stuff dating back to
the early seventies.


** Even the earliest germanium ones were DC coupled and had DC feedback
loops.

See above - Pat the Turd's ****ing idiot remark was made about ALL
transistor amps - not rare ones.



** So you see direct coupled, transformerless tubes amps all over the
place


Well, there are OTL amps, but for the most part direct coupled tube amps
are rather difficult
and ackward to do. If you want any voltage gain....


** Now you are utterly OFF TOPIC .


My point was that,....


** You never had an on topic point to make.

No go figure how some ****ing halfwit named Pat Turner would reach the
conclusion that all SS amps have a low frequency pole at 500 Hz ?????

Then figure how he imagined it was inside the NFB loop ???

Then you will know what MORON he is.




............ Phil

On Fri, 28 Nov 2003 11:13:11 +1100, "Phil Allison" wrote:



** Virtually all SS amps are direct coupled internally - ie they have full
open loop gain at DC.


Don't you mean they have controlled or lower gain at DC? Full open loop gain means no feedback, right?

But direct coupling means that the feedback loop is not open for DC.

Some amps (most?) use a cap to divide the feedback level going into the neg input so that there would be no division at
DC therefore less gain? Same as a signal of 50 gigahertz wouldn't pass thru the feedback network since it would be
totally shorted by this capacitor... so the amp would be open loop for signals this high... of course they can't get
thru but that's just illustrating the opposite of DC...

Or you are using terminology in a different way... don't get mad, Phil, I'm merely asking a question.

Bob

"Bob Flint"

"Phil Allison" wrote:

** Virtually all SS amps are direct coupled internally - ie they have
full
open loop gain at DC.


Don't you mean they have controlled or lower gain at DC?


** What is the topic Bob?

Did you read the thread or not ??

Did you read the post I am saying is wrong???

This one:

" Transistor amps typically have an open loop response curve that looks like
an arch, with a peak at 500 Hz, and rolling off
at 6 dB/octave either side. "


Full open loop gain means no feedback, right?


** The topic is OPEN LOOP gain of SS amps and how it varies with
frequency.


But direct coupling means that the feedback loop is not open for DC.


** Direct coupling means there is NO low frequency pole INSIDE the NFB
loop.


Or you are using terminology in a different way... don't get mad, Phil,
I'm merely asking a question.


** The topic is IS open loop gain - ie the inherent circuit signal gain
WITHOUT the feedback loop reducing it.

One has to remove or nullify the NFB loop to see what that gain is
and how it may vary with frequency.

For nearly all SS amps open loop gain is at its MAXIMUM value for
DC and low frequencies - exactly because they are DIRECT COUPLED. This is
sooooo simple, there is no reason for the inherent gain to drop at low
frequencies ** SO IT DOES NOT **.



......... Phil

Phil Allison wrote:

** Where is Pat Turner ????

Has he got his head buried in the sand or is it permanently up his own
backside ????

The posturing old fart posted this piece of crazy crap a few days back and
all his loyal arselickers ate it up !!!

" Transistor amps typically have an open loop response curve that looks like
an arch, with a peak at 500 Hz, and rolling off
at 6 dB/octave either side. "

Does NOBODY here have a clue how a SS amp actually works ????

Does NOBODY know that a SS amps has full its open loop gain down to DC ????

Does NOBODY dare challenge any of the excreta dropped from Turner the
Turd's bum on the world ????

His considered "New cathode bias method" cannot work as claimed
ither - that 1000uF will still charge up significantly on a steady drive
signal while the transistor does SFA about it.

Seems Pat Turner is not the ONLY stupid damn ostrich round here - the
place is overrun by them

.......... Phil

There ARE plenty of SS amps which have their maximum open loop
gain between 100Hz and 1 kHz.
NFB flattens the response.

I have repaired many like this.

The power supply caps in a complementary
pair output pair, even when all is direct coupled,
prevent useful gain at DC.
But many SS amps do have wider open loop response than
one decade. The ones I make sure do.

Until you build a tube amp with the
AC regulated cathode bias, you just won't know what a fool you are to state
that my new cathode bias ciruit actually does work,
exactly as described

You say :-

" His considered "New cathode bias method" cannot work as claimed
ither - that 1000uF will still charge up significantly on a steady drive
signal while the transistor does SFA about it."

The 10 ohm R in series with the RC bias circuit has an AV signal
across it, and when it rises to certain threshold value,
the transistors turn on, shunting the positive peaks in the cathode current,
which can be quite high when the amp has a low RL, and is working hard in class
AB.
Thus there is vastly reduced charge current that would otherwise
raise the voltage across the 1,000 uF, since it flows through
the transistor to ground on each side of the PP circuit.

You are skilled repairist of electronic equipment,
and you have designed some decent SS schematics of your own.

That you condemn my design without correctly analysing it,
or trying it out, has me thinking that your technical abilities are
as limited as your communication skills which are
so overly anally fixated and insulting, that reading you posts is often such
an utter bore.

Patrick Turner.

Robert Casey wrote:




" Transistor amps typically have an open loop response curve that looks like
an arch, with a peak at 500 Hz, and rolling off
at 6 dB/octave either side. "


Does NOBODY here have a clue how a SS amp actually works ????

Does NOBODY know that a SS amps has full its open loop gain down to DC ????



I was puzzled by the above "looks like an arch" statement. Modern power
transistors are capable of
doing several MHz frequency response, and the signal level ones can
operate up into the VHF
range. And all can do DC.

I said " open loop response ".

This is the response without any feedback applied.

When FB is applied in the usual globally applied loop,
the amount at say 1kHz might be 60 dB, and that's where
minimum thd occurs, and maximum gain reduction,
down to the level of the flat response of the
amp with feedback connected, which is called the
closed loop response.


So, what a SS amp can do would be dictated
by the other
parts in the amp. Now, if one has a few slow op-amps in that SS amp,
and some relatively small
coupling caps, then maybe the open loop gain might look like that arch.

Indeed.
I was very general about what I said.
Pentode amps also display an open loop response that is like an arch,
and of closer -3dB poles than when the loop is closed,
which makes the -3dB poles further apart,
although a large reduction in gain occurs.


It depends on
the design of the SS amp as to if it can do DC or if it ends up looking
like an arch. Same thing
with tubes. There the coupling caps, transformers and such dictate the
response. Though DC
coupling with a tube amp is rather difficult, as there are no
complements to electron tubes.

RC coupling and transformer coupling with transistor amps
was commonly done, and some have capacitor feed to the
speaker loads.
Most transistor amps are direct coupled, because
its easy to do with npn, and pnp devices,
and its the cheapest way to make an amp.

My 50 watt class A mosfet amp has both an OPT,
and RC coupling between the driver stage and output mosfets, see
http://www.turneraudio.com.au/htmlwe...5050mosfet.htm

I am considering changing the input transistors to
2sk369 j-fets, since I think it might improve the sound.

Patrick Turner.

"Patrick Turner" wrote in message
...
:
:
: Robert Casey wrote:
:
:
:
:
: " Transistor amps typically have an open loop response curve that looks
like
: an arch, with a peak at 500 Hz, and rolling off
: at 6 dB/octave either side. "
:
:
:
Guys, wanna get it straight get this, then, hear me now

I can

really



get to class, pronto maximissimus is muse a re duce
hehe

tease: got yer pathetically simpel doppler prob
wrote a 3 page, *real phisiacts* model for ya,

matter of 10 min or so

ne one match that, no peaky peaky stuff ?

I DARE
the world,
right now!

impressed ?

o,
guess not !!!!!!!!!!!!!!!!!!
Rudy

Phil said :-

See above - Pat the Turd's ****ing idiot remark was made about ALL
transistor amps - not rare ones.

I said above this :-

Transistor amps typically have an open loop response curve that looks like
an arch, with a peak at 500 Hz, and rolling off
at 6 dB/octave either side.

Typically!

There are many exceptions,
depending on design.
The general point I make is that
the open loop response of SS amps isn't very wide, which does not matter,
since FB will correct the open loop response to something useful.

As usual, Phil is just here at RAT to
twist the truth to defame me, and many other rational thinkers here,
who refrain from the foul mouthed gutter talk.

Patrick Turner.

"Ruud Broens" wrote in message
...
:
::
:
: get to class, pronto maximissimus is muse a re duce
: hehe
:
: tease: got yer pathetically simpel doppler prob
: wrote a 3 page, *real phisiacts* model for ya,
:
: matter of 10 min or so
:
: ne one match that, no peaky peaky stuff ?
:
: I DARE
: the world,
: right now!
:
: impressed ?
:
: o,
: guess not !!!!!!!!!!!!!!!!!!
: Rudy
:
O yo, mate Kevin, listen me out here,
if i were *your* type - well, not in *that* way-
i would be saying something here like:

"Now, guess have to ask, here, who *really*
doesn't does not nada niente baby UNDER.stand ??""

(btw, how does that feel, see it NOW ?)

"Ruud Broens" wrote in message
...

"Patrick Turner" wrote in message
...
:
:
: Robert Casey wrote:
:
:
:
:
: " Transistor amps typically have an open loop response curve that
looks
like
: an arch, with a peak at 500 Hz, and rolling off
: at 6 dB/octave either side. "
:
:
:
Guys, wanna get it straight get this, then, hear me now

I can

really



get to class, pronto maximissimus is muse a re duce
hehe

tease: got yer pathetically simpel doppler prob
wrote a 3 page, *real phisiacts* model for ya,

matter of 10 min or so

ne one match that, no peaky peaky stuff ?

I DARE
the world,
right now!

impressed ?

o,
guess not !!!!!!!!!!!!!!!!!!
Rudy


It's hard for me to argue with any of this, Rudy.... A flat gain/frequency
graph is a design goal. Peaky peaky stuff and arches should be kept below
40% if possible. Arches are actually a very good way of getting from one
side to the other without having to walk all the way round. The Romans
discovered the sine wave and the hole in the wall, so did round topped
ones, but the Normans went in for more pointy things. Norman was French,
after all.
Look very nice and easy to do with a wooden former, a few bricks and half a
barrow of mortar. Let it go off, overnight, brick up round it and you can
rest the planet on it, tomorrow.
After a week, distortion is not measureable.
Neither the Romans or Norman made a valve amp or a motorcycle which was
worth a damn, though.
I don't know whether anybody has noticed, by the way, but the original
Brimar 6SL7, when hoplessly overdriven, produces a CRO trace very similar
to a female breast when viewed from above...... X and Y axis adjustments
and varying the input can produce any shape you like. Can Bill Gates see my
CRO ?? Scotland Yard could arrest me for downloading underage toooobs !!

Regards, as always. Enjoying my TOOOOBS and trying not to take life too
seriously..
jim

"jim" wrote in message
...
: It's hard for me to argue with any of this, Rudy.... A flat
gain/frequency
: graph is a design goal. Peaky peaky stuff and arches should be kept below
: 40% if possible. Arches are actually a very good way of getting from one
: side to the other without having to walk all the way round. The Romans
: discovered the sine wave and the hole in the wall, so did round topped
: ones, but the Normans went in for more pointy things. Norman was French,
: after all.
: Look very nice and easy to do with a wooden former, a few bricks and half
a
: barrow of mortar. Let it go off, overnight, brick up round it and you can
: rest the planet on it, tomorrow.
: After a week, distortion is not measureable.
: Neither the Romans or Norman made a valve amp or a motorcycle which was
: worth a damn, though.
: I don't know whether anybody has noticed, by the way, but the original
: Brimar 6SL7, when hoplessly overdriven, produces a CRO trace very similar
: to a female breast when viewed from above...... X and Y axis adjustments
: and varying the input can produce any shape you like. Can Bill Gates see
my
: CRO ?? Scotland Yard could arrest me for downloading underage toooobs !!
:
: Regards, as always. Enjoying my TOOOOBS and trying not to take life too
: seriously..
: jim
:
jim, cut it, will ya,
we might have to
start calling ya "Art"

very nice
~~~~

"Ruud Broens" wrote in message
...

"jim" wrote in message
...
: It's hard for me to argue with any of this, Rudy.... A flat
gain/frequency
: graph is a design goal. Peaky peaky stuff and arches should be kept
below
: 40% if possible. Arches are actually a very good way of getting from
one
: side to the other without having to walk all the way round. The Romans
: discovered the sine wave and the hole in the wall, so did round topped
: ones, but the Normans went in for more pointy things. Norman was
French,
: after all.
: Look very nice and easy to do with a wooden former, a few bricks and
half
a
: barrow of mortar. Let it go off, overnight, brick up round it and you
can
: rest the planet on it, tomorrow.
: After a week, distortion is not measureable.
: Neither the Romans or Norman made a valve amp or a motorcycle which was
: worth a damn, though.
: I don't know whether anybody has noticed, by the way, but the original
: Brimar 6SL7, when hoplessly overdriven, produces a CRO trace very
similar
: to a female breast when viewed from above...... X and Y axis
adjustments
: and varying the input can produce any shape you like. Can Bill Gates
see
my
: CRO ?? Scotland Yard could arrest me for downloading underage toooobs
!!
:
: Regards, as always. Enjoying my TOOOOBS and trying not to take life too
: seriously..
: jim
:
jim, cut it, will ya,
we might have to
start calling ya "Art"

very nice
~~~~


Garfunkel ??

jim

"jim" wrote in message
...
:
: :
: jim, cut it, will ya,
: we might have to
: start calling ya "Art"
:
: very nice
: ~~~~
:
:
: Garfunkel ??
:
: jim
:
errr, was *that* a brit, 2

~~~~

"Patrick Turner" wrote in message
...
Phil said :-

See above - Pat the Turd's ****ing idiot remark was made about ALL
transistor amps - not rare ones.

I said above this :-

Transistor amps typically have an open loop response curve that looks like
an arch, with a peak at 500 Hz, and rolling off at 6 dB/octave either
side.

Typically!


** Not one SS amp ever made does that - you pig ignorant charlatan and
criminal piece of scum.

You have no technical knowledge at all - so **** OFF !!!!!!!!

You have no morals at all - so go to hell and BURN !!!





........... Phil

"Patrick Turner"



** You are a lying, ****ing piece of GARBAGE !!!!!!





.............. Phil

"Ruud Broens" wrote in message
...

"jim" wrote in message
...
:
: :
: jim, cut it, will ya,
: we might have to
: start calling ya "Art"
:
: very nice
: ~~~~
:
:
: Garfunkel ??
:
: jim
:
errr, was *that* a brit, 2

~~~~


Where've you been for the last forty years !! Paul Simon/Art Garfunkel ??
Doesn't ring any bells ??
Somebody put this guy, right !! He was asleep between 1960 and 1990.

Why do I get involved with Dutch people.?? Tulips and windmills... Peaky
peaky stuff and arches.. JEEEEEEZ !! Stick yer finger in this dyke
please..... The entire nation is forty feet below sea level. ...... and...
give us a hand, please.. The Germans are kicking the **** out of us ...
again.

Garfunkel !! British ?? With a name like that !! Good Lord !! Hardly
Anglo Saxon is it ? Bugger him off back to Alfa Romeo, on the next
boat.....

Harmless daft old friendly *******
jim

"Patrick Turner" wrote in message
...


Phil Allison wrote:

** Where is Pat Turner ????

Has he got his head buried in the sand or is it permanently up his own
backside ????

The posturing old fart posted this piece of crazy crap a few days back
and
all his loyal arselickers ate it up !!!

" Transistor amps typically have an open loop response curve that looks
like
an arch, with a peak at 500 Hz, and rolling off
at 6 dB/octave either side. "

Does NOBODY here have a clue how a SS amp actually works ????

Does NOBODY know that a SS amps has full its open loop gain down to DC
????

Does NOBODY dare challenge any of the excreta dropped from Turner the
Turd's bum on the world ????

His considered "New cathode bias method" cannot work as claimed
ither - that 1000uF will still charge up significantly on a steady
drive
signal while the transistor does SFA about it.

Seems Pat Turner is not the ONLY stupid damn ostrich round here - the
place is overrun by them

.......... Phil


There ARE plenty of SS amps which have their maximum open loop
gain between 100Hz and 1 kHz.


** There are NONE.

Time for you to say HOW you measure open loop response of an SS amp.

Your method is faulty.





The power supply caps in a complementary
pair output pair, even when all is direct coupled,
prevent useful gain at DC.


** Insanity to even say such a nonsense.


Snip rest of Turner the Turd's desperate, stupid lies .

He posts no case so there is none to answer.





.............. Phil

"jim" wrote in message
...
:
: "Ruud Broens" wrote in message
: ...
:
: "jim" wrote in message
: ...
: :
: : :
: : jim, cut it, will ya,
: : we might have to
: : start calling ya "Art"
: :
: : very nice
: : ~~~~
: :
: :
: : Garfunkel ??
: :
: : jim
: :
: errr, was *that* a brit, 2
:
: ~~~~
:
:
: Where've you been for the last forty years !! Paul Simon/Art Garfunkel
??
: Doesn't ring any bells ??
: Somebody put this guy, right !! He was asleep between 1960 and 1990.
:
: Why do I get involved with Dutch people.?? Tulips and windmills...
Peaky
: peaky stuff and arches.. JEEEEEEZ !! Stick yer finger in this
dyke
: please..... The entire nation is forty feet below sea level. ...... and...
: give us a hand, please.. The Germans are kicking the **** out of us
....
: again.
:
: Garfunkel !! British ?? With a name like that !! Good Lord !! Hardly
: Anglo Saxon is it ? Bugger him off back to Alfa Romeo, on the next
: boat.....
:
: Harmless daft old friendly *******
: jim
there, now you done it again
tiz me poor stomach
so much to take
all this d'mn joking
around the clock
~~~~
oh, btw, i stuck *my* head in da bookz ....mostly

"Ruud Broens" wrote in message
...

"jim" wrote in message
...
:
: "Ruud Broens" wrote in message
: ...
:
: "jim" wrote in message
: ...
: :
: : :
: : jim, cut it, will ya,
: : we might have to
: : start calling ya "Art"
: :
: : very nice
: : ~~~~
: :
: :
: : Garfunkel ??
: :
: : jim
: :
: errr, was *that* a brit, 2
:
: ~~~~
:
:
: Where've you been for the last forty years !! Paul Simon/Art Garfunkel
??
: Doesn't ring any bells ??
: Somebody put this guy, right !! He was asleep between 1960 and 1990.
:
: Why do I get involved with Dutch people.?? Tulips and windmills...
Peaky
: peaky stuff and arches.. JEEEEEEZ !! Stick yer finger in this
dyke
: please..... The entire nation is forty feet below sea level. ......
and...
: give us a hand, please.. The Germans are kicking the **** out of us
...
: again.
:
: Garfunkel !! British ?? With a name like that !! Good Lord !! Hardly
: Anglo Saxon is it ? Bugger him off back to Alfa Romeo, on the next
: boat.....
:
: Harmless daft old friendly *******
: jim
there, now you done it again
tiz me poor stomach
so much to take
all this d'mn joking
around the clock
~~~~
oh, btw, i stuck *my* head in da bookz ....mostly


You'd do better sticking your head in a dyke... or....you could be eating an
underwater meal tonight !!!
kindest regards, Rudy
jim

"jim" wrote in message
...
:
: "Ruud Broens" wrote in message
: ...
:
: "jim" wrote in message
: ...
: :
: : "Ruud Broens" wrote in message
: : ...
: :
: : "jim" wrote in
message
: : ...
: : :
: : : :
: : : jim, cut it, will ya,
: : : we might have to
: : : start calling ya "Art"
: : :
: : : very nice
: : : ~~~~
: : :
: : :
: : : Garfunkel ??
: : :
: : : jim
: : :
: : errr, was *that* a brit, 2
: :
: : ~~~~
: :
: :
: : Where've you been for the last forty years !! Paul Simon/Art
Garfunkel
: ??
: : Doesn't ring any bells ??
: : Somebody put this guy, right !! He was asleep between 1960 and
1990.
: :
: : Why do I get involved with Dutch people.?? Tulips and windmills...
: Peaky
: : peaky stuff and arches.. JEEEEEEZ !! Stick yer finger in this
: dyke
: : please..... The entire nation is forty feet below sea level. ......
: and...
: : give us a hand, please.. The Germans are kicking the **** out of
us
: ...
: : again.
: :
: : Garfunkel !! British ?? With a name like that !! Good Lord !!
Hardly
: : Anglo Saxon is it ? Bugger him off back to Alfa Romeo, on the next
: : boat.....
: :
: : Harmless daft old friendly *******
: : jim
: there, now you done it again
: tiz me poor stomach
: so much to take
: all this d'mn joking
: around the clock
: ~~~~
: oh, btw, i stuck *my* head in da bookz ....mostly
:
:
: You'd do better sticking your head in a dyke... or....you could be eating
an
: underwater meal tonight !!!
: kindest regards, Rudy
: jim
:
that is it !
a stomach *has* other uses, ya know
now, where was me blinders...
~~~~

"Ruud Broens" wrote in message
...

"jim" wrote in message
...
:
: "Ruud Broens" wrote in message
: ...
:
: "jim" wrote in message
: ...
: :
: : "Ruud Broens" wrote in message
: : ...
: :
: : "jim" wrote in
message
: : ...
: : :
: : : :
: : : jim, cut it, will ya,
: : : we might have to
: : : start calling ya "Art"
: : :
: : : very nice
: : : ~~~~
: : :
: : :
: : : Garfunkel ??
: : :
: : : jim
: : :
: : errr, was *that* a brit, 2
: :
: : ~~~~
: :
: :
: : Where've you been for the last forty years !! Paul Simon/Art
Garfunkel
: ??
: : Doesn't ring any bells ??
: : Somebody put this guy, right !! He was asleep between 1960 and
1990.
: :
: : Why do I get involved with Dutch people.?? Tulips and
windmills...
: Peaky
: : peaky stuff and arches.. JEEEEEEZ !! Stick yer finger in
this
: dyke
: : please..... The entire nation is forty feet below sea level. ......
: and...
: : give us a hand, please.. The Germans are kicking the **** out of
us
: ...
: : again.
: :
: : Garfunkel !! British ?? With a name like that !! Good Lord !!
Hardly
: : Anglo Saxon is it ? Bugger him off back to Alfa Romeo, on the next
: : boat.....
: :
: : Harmless daft old friendly *******
: : jim
: there, now you done it again
: tiz me poor stomach
: so much to take
: all this d'mn joking
: around the clock
: ~~~~
: oh, btw, i stuck *my* head in da bookz ....mostly
:
:
: You'd do better sticking your head in a dyke... or....you could be
eating
an
: underwater meal tonight !!!
: kindest regards, Rudy
: jim
:
that is it !
a stomach *has* other uses, ya know
now, where was me blinders...
~~~~



Yes.... Strap a Garfunkel round yer head, put a pair of blinders on, grab a
tulip and **** off outside to see if you are still above water.....
jim

"jim" wrote in message
...
:
: "Ruud Broens" wrote in message
: ...
:
: "jim" wrote in message
: ...
: :
: : "Ruud Broens" wrote in message
: : ...
: :
: : "jim" wrote in
message
: : ...
: : :
: : : "Ruud Broens" wrote in message
: : : ...
: : :
: : : "jim" wrote in
: message
: : : ...
: : : :
: : : : :
: : : : jim, cut it, will ya,
: : : : we might have to
: : : : start calling ya "Art"
: : : :
: : : : very nice
: : : : ~~~~
: : : :
: : : :
: : : : Garfunkel ??
: : : :
: : : : jim
: : : :
: : : errr, was *that* a brit, 2
: : :
: : : ~~~~
: : :
: : :
: : : Where've you been for the last forty years !! Paul Simon/Art
: Garfunkel
: : ??
: : : Doesn't ring any bells ??
: : : Somebody put this guy, right !! He was asleep between 1960 and
: 1990.
: : :
: : : Why do I get involved with Dutch people.?? Tulips and
: windmills...
: : Peaky
: : : peaky stuff and arches.. JEEEEEEZ !! Stick yer finger in
: this
: : dyke
: : : please..... The entire nation is forty feet below sea level.
.......
: : and...
: : : give us a hand, please.. The Germans are kicking the **** out
of
: us
: : ...
: : : again.
: : :
: : : Garfunkel !! British ?? With a name like that !! Good Lord !!
: Hardly
: : : Anglo Saxon is it ? Bugger him off back to Alfa Romeo, on the
next
: : : boat.....
: : :
: : : Harmless daft old friendly *******
: : : jim
: : there, now you done it again
: : tiz me poor stomach
: : so much to take
: : all this d'mn joking
: : around the clock
: : ~~~~
: : oh, btw, i stuck *my* head in da bookz ....mostly
: :
: :
: : You'd do better sticking your head in a dyke... or....you could be
: eating
: an
: : underwater meal tonight !!!
: : kindest regards, Rudy
: : jim
: :
: that is it !
: a stomach *has* other uses, ya know
: now, where was me blinders...
: ~~~~
:
:
:
: Yes.... Strap a Garfunkel round yer head, put a pair of blinders on, grab
a
: tulip and **** off outside to see if you are still above water.....
: jim
:
God...i'm 'only' human - getting the 1st aid tummy pack in action..hehe
~~~~

"Ruud Broens" wrote in message
...
:
: "jim" wrote in message
: ...
: :
: : "Ruud Broens" wrote in message
: : ...
: :
: : "jim" wrote in message
: : ...
: : :
: : : "Ruud Broens" wrote in message
: : : ...
: : :
: : : "jim" wrote in
: message
: : : ...
: : : :
: : : : "Ruud Broens" wrote in message
: : : : ...
: : : :
: : : : "jim" wrote in
: : message
: : : : ...
: : : : :
: : : : : :
: : : : : jim, cut it, will ya,
: : : : : we might have to
: : : : : start calling ya "Art"
: : : : :
: : : : : very nice
: : : : : ~~~~
: : : : :
: : : : :
: : : : : Garfunkel ??
: : : : :
: : : : : jim
: : : : :
: : : : errr, was *that* a brit, 2
: : : :
: : : : ~~~~
: : : :
: : : :
: : : : Where've you been for the last forty years !! Paul Simon/Art
: : Garfunkel
: : : ??
: : : : Doesn't ring any bells ??
: : : : Somebody put this guy, right !! He was asleep between 1960
and
: : 1990.
: : : :
: : : : Why do I get involved with Dutch people.?? Tulips and
: : windmills...
: : : Peaky
: : : : peaky stuff and arches.. JEEEEEEZ !! Stick yer finger
in
: : this
: : : dyke
: : : : please..... The entire nation is forty feet below sea level.
: ......
: : : and...
: : : : give us a hand, please.. The Germans are kicking the ****
out
: of
: : us
: : : ...
: : : : again.
: : : :
: : : : Garfunkel !! British ?? With a name like that !! Good Lord !!
: : Hardly
: : : : Anglo Saxon is it ? Bugger him off back to Alfa Romeo, on the
: next
: : : : boat.....
: : : :
: : : : Harmless daft old friendly *******
: : : : jim
: : : there, now you done it again
: : : tiz me poor stomach
: : : so much to take
: : : all this d'mn joking
: : : around the clock
: : : ~~~~
: : : oh, btw, i stuck *my* head in da bookz ....mostly
: : :
: : :
: : : You'd do better sticking your head in a dyke... or....you could be
: : eating
: : an
: : : underwater meal tonight !!!
: : : kindest regards, Rudy
: : : jim
: : :
: : that is it !
: : a stomach *has* other uses, ya know
: : now, where was me blinders...
: : ~~~~
: :
: :
: :
: : Yes.... Strap a Garfunkel round yer head, put a pair of blinders on,
grab
: a
: : tulip and **** off outside to see if you are still above water.....
: : jim
: :
: God...i'm 'only' human - getting the 1st aid tummy pack in action..hehe
: ~~~~
: o, btw, where *did* you hide your UFO
we wanna know
needs a lift to another dim
hehe
~~~~
:

"Ruud Broens" wrote in message
...
:
: : : : : : : :
: : : : : : jim, cut it, will ya,
: : : : : : we might have to
: : : : : : start calling ya "Art"
: : : : : :
: : : : : : very nice
: : : : : : ~~~~
: : : : : :
: : : : : :
: : : : : : Garfunkel ??
: : : : : :
: : : : : : jim
: : : : : :
: : : : : errr, was *that* a brit, 2
: : : : :
: : : : : ~~~~
: : : : :
: : : : :
: : : : : Where've you been for the last forty years !! Paul Simon/Art
: : : Garfunkel
: : : : ??
: : : : : Doesn't ring any bells ??
: : : : : Somebody put this guy, right !! He was asleep between 1960
: and
: : : 1990.
: : : : :
: : : : : Why do I get involved with Dutch people.?? Tulips and
: : : windmills...
: : : : Peaky
: : : : : peaky stuff and arches.. JEEEEEEZ !! Stick yer finger
: in
: : : this
: : : : dyke
: : : : : please..... The entire nation is forty feet below sea level.
: : ......
: : : : and...
: : : : : give us a hand, please.. The Germans are kicking the ****
: out
: : of
: : : us
: : : : ...
: : : : : again.
: : : : :
: : : : : Garfunkel !! British ?? With a name like that !! Good Lord
!!
: : : Hardly
: : : : : Anglo Saxon is it ? Bugger him off back to Alfa Romeo, on
the
: : next
: : : : : boat.....
: : : : :
: : : : : Harmless daft old friendly *******
: : : : : jim
: : : : there, now you done it again
: : : : tiz me poor stomach
: : : : so much to take
: : : : all this d'mn joking
: : : : around the clock
: : : : ~~~~
: : : : oh, btw, i stuck *my* head in da bookz ....mostly
: : : :
: : : :
: : : : You'd do better sticking your head in a dyke... or....you could be
: : : eating
: : : an
: : : : underwater meal tonight !!!
: : : : kindest regards, Rudy
: : : : jim
: : : :
: : : that is it !
: : : a stomach *has* other uses, ya know
: : : now, where was me blinders...
: : : ~~~~
: : :
: : :
: : :
: : : Yes.... Strap a Garfunkel round yer head, put a pair of blinders on,
: grab
: : a
: : : tulip and **** off outside to see if you are still above water.....
: : : jim
: : :
: : God...i'm 'only' human - getting the 1st aid tummy pack in action..hehe
: : ~~~~
: : o, btw, where *did* you hide your UFO
: we wanna know
: needs a lift to another dim
: hehe
: ~~~~
NB ther's a slowhand for ya, the guy needin' a lift *was* here
or did u have a hand in that, 2
:
:

"Ruud Broens" wrote in message
...

"Ruud Broens" wrote in message
...
:
: "jim" wrote in message
: ...
: :
: : "Ruud Broens" wrote in message
: : ...
: :
: : "jim" wrote in
message
: : ...
: : :
: : : "Ruud Broens" wrote in message
: : : ...
: : :
: : : "jim" wrote in
: message
: : : ...
: : : :
: : : : "Ruud Broens" wrote in message
: : : : ...
: : : :
: : : : "jim" wrote
in
: : message
: : : : ...
: : : : :
: : : : : :
: : : : : jim, cut it, will ya,
: : : : : we might have to
: : : : : start calling ya "Art"
: : : : :
: : : : : very nice
: : : : : ~~~~
: : : : :
: : : : :
: : : : : Garfunkel ??
: : : : :
: : : : : jim
: : : : :
: : : : errr, was *that* a brit, 2
: : : :
: : : : ~~~~
: : : :
: : : :
: : : : Where've you been for the last forty years !! Paul Simon/Art
: : Garfunkel
: : : ??
: : : : Doesn't ring any bells ??
: : : : Somebody put this guy, right !! He was asleep between 1960
and
: : 1990.
: : : :
: : : : Why do I get involved with Dutch people.?? Tulips and
: : windmills...
: : : Peaky
: : : : peaky stuff and arches.. JEEEEEEZ !! Stick yer finger
in
: : this
: : : dyke
: : : : please..... The entire nation is forty feet below sea level.
: ......
: : : and...
: : : : give us a hand, please.. The Germans are kicking the ****
out
: of
: : us
: : : ...
: : : : again.
: : : :
: : : : Garfunkel !! British ?? With a name like that !! Good Lord
!!
: : Hardly
: : : : Anglo Saxon is it ? Bugger him off back to Alfa Romeo, on
the
: next
: : : : boat.....
: : : :
: : : : Harmless daft old friendly *******
: : : : jim
: : : there, now you done it again
: : : tiz me poor stomach
: : : so much to take
: : : all this d'mn joking
: : : around the clock
: : : ~~~~
: : : oh, btw, i stuck *my* head in da bookz ....mostly
: : :
: : :
: : : You'd do better sticking your head in a dyke... or....you could be
: : eating
: : an
: : : underwater meal tonight !!!
: : : kindest regards, Rudy
: : : jim
: : :
: : that is it !
: : a stomach *has* other uses, ya know
: : now, where was me blinders...
: : ~~~~
: :
: :
: :
: : Yes.... Strap a Garfunkel round yer head, put a pair of blinders on,
grab
: a
: : tulip and **** off outside to see if you are still above water.....
: : jim
: :
: God...i'm 'only' human - getting the 1st aid tummy pack in action..hehe
: ~~~~
: o, btw, where *did* you hide your UFO
we wanna know
needs a lift to another dim
hehe
~~~~
:

Kofi Annan and the UN have now renamed, Holland/The Netherlands as U96...
It's mostly underwater so it is, now, an attack submarine... Karl Heinrich
Schlasser will be around this evening to take command... He is familiar
with The Netherlands.. He is German... He knows about U Boats... Rudy ..
You will be in the forward torpedo room...

Tonight, you mount, a one sided, single handed, backs to the wall, no
prisoners, strike, on Dyptheria, in the NW corner of the southern edge of
the bit which sticks up off the left hand corner of Indonesia... Under
Osima Beentheredonethat, they are trying to establish a radical Quaker
nation and really need a serious kicking.

Have no worries.. George is by your side.

I am forwarding a copy of the film ... Run Silent, Run Deep.. on video..
Andrew Jullison and Dirk Mudguard ... 1947 remake of the epic .....'Sink
the Skidmark'

It may be helpful...

kind regards
jim

Hey Rudy,

You probably aren't aware of this, but your
good buddy Kevin doesn't post or monitor this
newsgroup....never has, never will. So your
efforts at impressing him are entirely wasted
when you post on rec.audio.tubes.

-Chuck

Ruud Broens wrote:

:
O yo, mate Kevin, listen me out here,
if i were *your* type - well, not in *that* way-
i would be saying something here like:

"Now, guess have to ask, here, who *really*
doesn't does not nada niente baby UNDER.stand ??""

(btw, how does that feel, see it NOW ?)

: : ~~~~
: : o, btw, where *did* you hide your UFO

Wolverhampton. It's a pile of ****, deriliction, bricks and rubble, just
north of Birmingham. Nobody would think of looking there for an
intergallactic time traveller....

: we wanna know
: needs a lift to another dim
: hehe
: ~~~~
NB ther's a slowhand for ya, the guy needin' a lift *was* here
or did u have a hand in that, 2
:

SSSHH, he did one of our Fly/Drive holidays to Mercury with free asbestos
shoes

regards
jim

"Chuck Harris" wrote in message
...
: Hey Rudy,
:
: You probably aren't aware of this, but your
: good buddy Kevin doesn't post or monitor this
: newsgroup....never has, never will. So your
: efforts at impressing him are entirely wasted
: when you post on rec.audio.tubes.
:
: -Chuck

I know Chuck, i know
but, don't ya worry...he WILL
a little later,
perhaps,
Rudy

On Fri, 28 Nov 2003 16:01:13 +1100, "Phil Allison" wrote:


"Bob Flint"

"Phil Allison" wrote:

** Virtually all SS amps are direct coupled internally - ie they have
full
open loop gain at DC.


Don't you mean they have controlled or lower gain at DC?


** What is the topic Bob?

Did you read the thread or not ??

Did you read the post I am saying is wrong???

This one:

" Transistor amps typically have an open loop response curve that looks like
an arch, with a peak at 500 Hz, and rolling off
at 6 dB/octave either side. "


Full open loop gain means no feedback, right?


** The topic is OPEN LOOP gain of SS amps and how it varies with
frequency.


But direct coupling means that the feedback loop is not open for DC.


** Direct coupling means there is NO low frequency pole INSIDE the NFB
loop.


Or you are using terminology in a different way... don't get mad, Phil,
I'm merely asking a question.


** The topic is IS open loop gain - ie the inherent circuit signal gain
WITHOUT the feedback loop reducing it.

One has to remove or nullify the NFB loop to see what that gain is
and how it may vary with frequency.

For nearly all SS amps open loop gain is at its MAXIMUM value for
DC and low frequencies - exactly because they are DIRECT COUPLED. This is
sooooo simple, there is no reason for the inherent gain to drop at low
frequencies ** SO IT DOES NOT **.

OK I get you now, you are just referring to the amp circuits being direct coupled and you don't care about the feedback
loop in this topic. You are right, logic dictates the amp would have reduced gain above the DC point.

So now what about any local feedback in each stage? Would you consider this to be removed as well in order to be open
loop? Or just the main overall loop... Perhaps that guy is referring to an amp with some odd local capacitance coupled
feedback in just 1 stage..

Bob Flint wrote:

On Fri, 28 Nov 2003 16:01:13 +1100, "Phil Allison" wrote:


"Bob Flint"

"Phil Allison" wrote:

** Virtually all SS amps are direct coupled internally - ie they have
full
open loop gain at DC.


Don't you mean they have controlled or lower gain at DC?


** What is the topic Bob?

Did you read the thread or not ??

Did you read the post I am saying is wrong???

This one:

" Transistor amps typically have an open loop response curve that looks like
an arch, with a peak at 500 Hz, and rolling off
at 6 dB/octave either side. "


Full open loop gain means no feedback, right?


** The topic is OPEN LOOP gain of SS amps and how it varies with
frequency.


But direct coupling means that the feedback loop is not open for DC.


** Direct coupling means there is NO low frequency pole INSIDE the NFB
loop.


Or you are using terminology in a different way... don't get mad, Phil,
I'm merely asking a question.


** The topic is IS open loop gain - ie the inherent circuit signal gain
WITHOUT the feedback loop reducing it.

One has to remove or nullify the NFB loop to see what that gain is
and how it may vary with frequency.

For nearly all SS amps open loop gain is at its MAXIMUM value for
DC and low frequencies - exactly because they are DIRECT COUPLED. This is
sooooo simple, there is no reason for the inherent gain to drop at low
frequencies ** SO IT DOES NOT **.

OK I get you now, you are just referring to the amp circuits being direct coupled and you don't care about the feedback
loop in this topic. You are right, logic dictates the amp would have reduced gain above the DC point.

So now what about any local feedback in each stage? Would you consider this to be removed as well in order to be open
loop? Or just the main overall loop... Perhaps that guy is referring to an amp with some odd local capacitance coupled
feedback in just 1 stage..

I said this :-

" Transistor amps typically have an open loop response curve that looks like
an arch, with a peak at 500 Hz, and rolling off
at 6 dB/octave either side. "

Unfortunately, ppl like Phil leapt on me to say how erroneous this is.
Its because he assumed I said the -3Db point in most amps was close as possible
to 500 Hz, but of course, a lot of what Phil assumes
is part of a foolish rush to crucify his target, myself, forever,
with a pile of foul language.
His assumption is plain wrong.
I did not say at what frequency either side of 500 Hz
was where roll off in response occurs.

In practice the LF pole and HF poles separated by
a bandwidth much smaller than when the FB is applied.
There is often a bandwidth limiting input filter which establishes
the input BW going to the amp, and this prevents the
SS amp from having a response down to DC, or 0.0 Hz.
The LF open loop BW even without the FB connected is
also somewhat marred by the PS caps, and if they were say 4,700 uF,
which isn't unusual, their impedance at 5 Hz would be 6.8 ohms,
and rising at 6 dB/octave towards DC.
The other rail filter caps also have rising impedance,
and basically, the SS amp has a useless open loop power ability
as F falls low.
At HF, there is RC compensation, ie a zobel network
placed across the gain block prior to driving the output stage,
so open loop gain is controlled by this RC network, to
reduce gain at above some F, anywhere between
100 Hz and say 5 kHz.
The peak in the response will be a broad one.

The open loop gain is usually designed to not have more than a
90 degree lag in the phase shift.
If this is true up to say 100 kHz,
then the application of FB will still allow good stability,
even with capacitor loads, because the effects of phase shift
by cap loads at the output is prevented by the LR zobel network.

Let us suppose the the maximum voltage open loop gain was say 10,000
or +80 dB at say 500 Hz, then for 28vo into 8 ohms, ( 100 watts ),
you'd need 2.83 mV if input to make the 28v output, without FB.
This isn't unusual for an SS amp.
Suppose we applied FB, so the input voltage was 1 v to make 28 vo,
then the gain reduction due to FB at 500 Hz is 20 log x 1/0.0028 = 51 dB.
(If the N&D was say 7% open loop, with FB its goes down
a similar 51 db to 0.0196%.)

Let's suppose the HF open loop pole was at 1 kHz.
The open response may well slope at 6 dB/octave,
out to say 10 kHz, so the open loop gain at 10 kHz is
not 80 dB, but more like 60 dB, and for 2.8mV input, we get only
2.8 vo.
The effect of the FB will be to flatten the response so vo
at 10 kHz is only a tiny amount down on the 1 kHz level.
The FB has reduced gain at 10 kHz by 31 dB,
and thd will be reduced from say 7% to 0.197%.
The figures are not unusual, but approximate, and don't
allow for the slight errors caused by open loop phase shift.
By 100 kHz, the applied FB has fallen to 10 dB,
and by 300 kHz, the FB stops having any effect on the gain.
The result of declining gain in all amps as F rises makes then stable at high F,
since phase shift increases as F rises, and we don't want gain to be above
1, or 0 dB, if the open loop phase shift has exceeded -180 dregrees.
If you have 180 degrees of phase shift, and more open gain than 1,
Then the amp will oscillate at some HF when FB is applied,
especially if the load is a medium capacitor load, say 0.22 uF,
and there is no zobel network.

It is possible to have wide bandwidth open loop amps,
but the majority of those in the shop have low open loop BW.
They usually measure a lot better than a tube amp.
But this doesn't mean they always sound better,
or that we should always use SS amps.

Patrick Turner.

"Phil Allison" wrote in message . au...

You have no technical knowledge at all - so **** OFF !!!!!!!!

You have no morals at all - so go to hell and BURN !!!

Temper, temper Phil!
M & M AM Aunt Joan P31

"Patrick Turner"


I said this :-

" Transistor amps typically have an open loop response curve that looks
like
an arch, with a peak at 500 Hz, and rolling off
at 6 dB/octave either side. "


Unfortunately, ppl like Phil leapt on me to say how erroneous this is.


** It is highly erroneous.



In practice the LF pole and HF poles separated by
a bandwidth much smaller than when the FB is applied.


** There is no LF pole inside the loop.



There is often a bandwidth limiting input filter which establishes
the input BW going to the amp, and this prevents the
SS amp from having a response down to DC, or 0.0 Hz.


** Outside the loop.



The LF open loop BW even without the FB connected is
also somewhat marred by the PS caps, and if they were say 4,700 uF,
which isn't unusual, their impedance at 5 Hz would be 6.8 ohms,
and rising at 6 dB/octave towards DC.

The other rail filter caps also have rising impedance,
and basically, the SS amp has a useless open loop power ability
as F falls low.


** The madness just gets worse and worse.

How does this lying ****WIT think a DC power supply works ??????




............ Phil

On Sat, 29 Nov 2003 19:30:16 +1100, Patrick Turner wrote:

I said this :-

" Transistor amps typically have an open loop response curve that looks like
an arch, with a peak at 500 Hz, and rolling off
at 6 dB/octave either side. "

OK - so where are you getting this 500hz from? I take it you are including the input coupling cap to keep DC out of the
amp, and the output stability cap and natural tendencies of the circuit to fall off at rising F., but I would have
thought all this contribution would peak at maybe 50Hz and then drop off...

Unfortunately, ppl like Phil leapt on me to say how erroneous this is.
Its because he assumed I said the -3Db point in most amps was close as possible
to 500 Hz, but of course, a lot of what Phil assumes
is part of a foolish rush to crucify his target, myself, forever,
with a pile of foul language.
His assumption is plain wrong.
I did not say at what frequency either side of 500 Hz
was where roll off in response occurs.

Are you implying it has a flat region around 500hz?

In practice the LF pole and HF poles separated by
a bandwidth much smaller than when the FB is applied.
There is often a bandwidth limiting input filter which establishes
the input BW going to the amp, and this prevents the
SS amp from having a response down to DC, or 0.0 Hz.

Don't some amps limit the FB loop as well so that DC has minimum gain?

The LF open loop BW even without the FB connected is
also somewhat marred by the PS caps, and if they were say 4,700 uF,
which isn't unusual, their impedance at 5 Hz would be 6.8 ohms,
and rising at 6 dB/octave towards DC.
The other rail filter caps also have rising impedance,
and basically, the SS amp has a useless open loop power ability
as F falls low.

Wouldn't problems due to power transfer from the supply caps show up with or without FB?? Normally it's just increased
distortion, why would the power out change due to lack of FB?

At HF, there is RC compensation, ie a zobel network
placed across the gain block prior to driving the output stage,
so open loop gain is controlled by this RC network, to
reduce gain at above some F, anywhere between
100 Hz and say 5 kHz.
The peak in the response will be a broad one.

Isn't this put there to reduce gain at high F so that phase above 150 or so is at a gain 1?

The open loop gain is usually designed to not have more than a
90 degree lag in the phase shift.
If this is true up to say 100 kHz,
then the application of FB will still allow good stability,
even with capacitor loads, because the effects of phase shift
by cap loads at the output is prevented by the LR zobel network.

OK... but some (most) amps require a tailored response in the FB loop as well or they go unstable, would testing an amp
open loop cause it to become unstable?

Let us suppose the the maximum voltage open loop gain was say 10,000
or +80 dB at say 500 Hz, then for 28vo into 8 ohms, ( 100 watts ),
you'd need 2.83 mV if input to make the 28v output, without FB.
This isn't unusual for an SS amp.
Suppose we applied FB, so the input voltage was 1 v to make 28 vo,
then the gain reduction due to FB at 500 Hz is 20 log x 1/0.0028 = 51 dB.
(If the N&D was say 7% open loop, with FB its goes down
a similar 51 db to 0.0196%.)

Let's suppose the HF open loop pole was at 1 kHz.
The open response may well slope at 6 dB/octave,
out to say 10 kHz, so the open loop gain at 10 kHz is
not 80 dB, but more like 60 dB, and for 2.8mV input, we get only
2.8 vo.

Most amps have a cumulative phase shift addition due to each stage... from what I remember in my designing days this can
add up to trouble fast! Some amps have very little open loop gain above 20khz.

The effect of the FB will be to flatten the response so vo
at 10 kHz is only a tiny amount down on the 1 kHz level.
The FB has reduced gain at 10 kHz by 31 dB,
and thd will be reduced from say 7% to 0.197%.
The figures are not unusual, but approximate, and don't
allow for the slight errors caused by open loop phase shift.
By 100 kHz, the applied FB has fallen to 10 dB,
and by 300 kHz, the FB stops having any effect on the gain.
The result of declining gain in all amps as F rises makes then stable at high F,
since phase shift increases as F rises, and we don't want gain to be above
1, or 0 dB, if the open loop phase shift has exceeded -180 dregrees.
If you have 180 degrees of phase shift, and more open gain than 1,
Then the amp will oscillate at some HF when FB is applied,
especially if the load is a medium capacitor load, say 0.22 uF,
and there is no zobel network.

Thanks for re-freshing my memory on theory!

It is possible to have wide bandwidth open loop amps,
but the majority of those in the shop have low open loop BW.
They usually measure a lot better than a tube amp.
But this doesn't mean they always sound better,
or that we should always use SS amps.

I use SS for my stereo, tube for my guitars...

Patrick Turner.

Patrick Turner wrote:

: I said this :-
:
: " Transistor amps typically have an open loop response curve that looks like
: an arch, with a peak at 500 Hz, and rolling off
: at 6 dB/octave either side. "
:
: Unfortunately, ppl like Phil leapt on me to say how erroneous this is.
: Its because he assumed I said the -3Db point in most amps was close as possible
: to 500 Hz, but of course, a lot of what Phil assumes
: is part of a foolish rush to crucify his target, myself, forever,
: with a pile of foul language.
: His assumption is plain wrong.
: I did not say at what frequency either side of 500 Hz
: was where roll off in response occurs.

I'm sorry, but to me, "a peak at 500 Hz, and rolling off
at 6 dB/octave either side " implies 6dB down at 250 Hz, and at 1000 Hz, &etc.
*quite* specifically. If you had meant a flattened arch, why say a peak at
500Hz? If you meant a broad arch (unspecified slopes) with a final 6db
roll-off at (unspecified freq) ends, why not say so? I find it confusing ...

"Ross Matheson" wrote in message .
Patrick Turner wrote:

: I said this :-
:
: " Transistor amps typically have an open loop response curve that looks
like
: an arch, with a peak at 500 Hz, and rolling off
: at 6 dB/octave either side. "
:
: Unfortunately, ppl like Phil leapt on me to say how erroneous this is.
: Its because he assumed I said the -3Db point in most amps was close as
possible
: to 500 Hz, but of course, a lot of what Phil assumes
: is part of a foolish rush to crucify his target, myself, forever,
: with a pile of foul language.
: His assumption is plain wrong.
: I did not say at what frequency either side of 500 Hz
: was where roll off in response occurs.

I'm sorry, but to me, "a peak at 500 Hz, and rolling off
at 6 dB/octave either side " implies 6dB down at 250 Hz, and at 1000 Hz,
&etc.
*quite* specifically. If you had meant a flattened arch, why say a peak at
500Hz? If you meant a broad arch (unspecified slopes) with a final 6db
roll-off at (unspecified freq) ends, why not say so? I find it confusing
....


** The same mental cripple posted this a few months ago:

" Tranny amps have open loop response of maybe -3 dB points at
20 Hz and 1 kHz, so the reponse graph looks like an arch."

Both comments are **completely false**.

There is no low frequency pole inside the feedback loop in typical SS power
amps - for the simple reason they are direct coupled. The open loop gain
figure at low frequencies holds right down to DC - the same is true for any
op-amp.

Hence there is no reduction in the closed loop feedback factor and
consequent rise in THD and output Z at low frequencies.



........... Phil

Bob Flint wrote:

On Sat, 29 Nov 2003 19:30:16 +1100, Patrick Turner wrote:

I said this :-

" Transistor amps typically have an open loop response curve that looks like
an arch, with a peak at 500 Hz, and rolling off
at 6 dB/octave either side. "

OK - so where are you getting this 500hz from? I take it you are including the input coupling cap to keep DC out of the
amp, and the output stability cap and natural tendencies of the circuit to fall off at rising F., but I would have
thought all this contribution would peak at maybe 50Hz and then drop off...

I was being very general about SS amps, in refering to their
OPEN LOOP response, ie, the measured response with
no global feedback connected, but with the input filter present, and the
"compensation" network to control HF gain, which srats to act somewhere above 500 Hz.
The actual poles where roll off start, ie, the -3 dB points for HF and LF
are usually either side of 500 Hz.



Unfortunately, ppl like Phil leapt on me to say how erroneous this is.
Its because he assumed I said the -3Db point in most amps was close as possible
to 500 Hz, but of course, a lot of what Phil assumes
is part of a foolish rush to crucify his target, myself, forever,
with a pile of foul language.
His assumption is plain wrong.
I did not say at what frequency either side of 500 Hz
was where roll off in response occurs.

Are you implying it has a flat region around 500hz?

Indeed.



In practice the LF pole and HF poles separated by
a bandwidth much smaller than when the FB is applied.
There is often a bandwidth limiting input filter which establishes
the input BW going to the amp, and this prevents the
SS amp from having a response down to DC, or 0.0 Hz.

Don't some amps limit the FB loop as well so that DC has minimum gain?

Not many.
Most SS amps have the maximum amount of FB applied AT 0.0Hz, ( DC )
There are two inputs to most SS amps, the one for the signal, from the input
filter which bandwidth limits the input,
and one for the feedback.
The feedback is derived with a reistance divider from the output, so
say 28v output is reduced to 1 v at the FB terminal.
The bottom resistor of the divider is often grounded
to 0V via a cap of around 100uF.
So in effect, at 0 Hz, the output signal is ALL fed back to the input,
and the amount of applied FB at 0 Hz is the maximum amount which can be applied.
Such an arrangement is possible in an otherwise totally direct coupled amplifier,
and the DV measured at the output has splendid stability.


The LF open loop BW even without the FB connected is
also somewhat marred by the PS caps, and if they were say 4,700 uF,
which isn't unusual, their impedance at 5 Hz would be 6.8 ohms,
and rising at 6 dB/octave towards DC.
The other rail filter caps also have rising impedance,
and basically, the SS amp has a useless open loop power ability
as F falls low.

Wouldn't problems due to power transfer from the supply caps show up with or without FB?? Normally it's just increased
distortion, why would the power out change due to lack of FB?

The power supply caps become open circuit at 0.0 Hz.
So as F falls, the amp output signal finds itself being intermodulated
by the 100 Hz ripple signal from the PS.
With FB, the effects of this are fed back, and the distortions caused are
amplified in opposite phase to cancel the N&D as it occurs, and the
PS IMD isn't a high figure.
But there is a power bandwidth, ie,
a power level where N&D rises above 0.1%,
and that rarely means full power at 1 Hz is available from an SS amp.

In my 2 x 300 watt mosfet class AB amp, I have 100,000 uF caps
for the +/- 70 volt rails, and the amp does
manage some very low F, still at low N&D, with or without any FB.

The other thing to remember is that most SS amps have their output devices set up in
emitter follower, or source follower, which is like cathode follower.
This is a form of local series voltage FB. It is usually about
20 to 40 dB in magnitude, and this reduces the N&D
in output stages to below maybe 2% at quite high power, without the
additional 50 dB of global FB.
So its not uncommon for an SS amp to have a total of 80 dB of FB.


At HF, there is RC compensation, ie a zobel network
placed across the gain block prior to driving the output stage,
so open loop gain is controlled by this RC network, to
reduce gain at above some F, anywhere between
100 Hz and say 5 kHz.
The peak in the response will be a broad one.

Isn't this put there to reduce gain at high F so that phase above 150 or so is at a gain 1?

Indeed.



The open loop gain is usually designed to not have more than a
90 degree lag in the phase shift.
If this is true up to say 100 kHz,
then the application of FB will still allow good stability,
even with capacitor loads, because the effects of phase shift
by cap loads at the output is prevented by the LR zobel network.

OK... but some (most) amps require a tailored response in the FB loop as well or they go unstable, would testing an amp
open loop cause it to become unstable?

Well yes, so a little cap across the feedback resistor is used to
advance the phase of the output signal at HF, to compensate
for the lag in phase in the open loop gain of the amp.
This extends the range of frequency over which the
FB is effective, ie, more FB is applied, but
its phase is adjusted just right.
Too big a feedback compo C causes oscillations.



Let us suppose the the maximum voltage open loop gain was say 10,000
or +80 dB at say 500 Hz, then for 28vo into 8 ohms, ( 100 watts ),
you'd need 2.83 mV if input to make the 28v output, without FB.
This isn't unusual for an SS amp.
Suppose we applied FB, so the input voltage was 1 v to make 28 vo,
then the gain reduction due to FB at 500 Hz is 20 log x 1/0.0028 = 51 dB.
(If the N&D was say 7% open loop, with FB its goes down
a similar 51 db to 0.0196%.)

Let's suppose the HF open loop pole was at 1 kHz.
The open response may well slope at 6 dB/octave,
out to say 10 kHz, so the open loop gain at 10 kHz is
not 80 dB, but more like 60 dB, and for 2.8mV input, we get only
2.8 vo.

Most amps have a cumulative phase shift addition due to each stage... from what I remember in my designing days this can
add up to trouble fast! Some amps have very little open loop gain above 20khz.

This is only true of the very worst amps.
In tube amps, because of the miller C between stages, and the
leakage inductance on the OPT, the roll off can begin early, and
there can be 180 degress of phase shift by 50 kHz, so
the RC zobel network across the V1 anode load is used to reduce the gain
starting at say 7 kHz, so that by 50 kHz the gain is reduced say 15 dB,
and the phase shift is no worse at 50 kHz, perhaps less than without the zobel network.
SS amps have problems with phase shift between the differential input amp,
and the main gain stage, which is usually has a high output
inpedance, which then has to cope with reducing input impedance of the output
stage as F rises.
HF open loop gain is then also stepped with a zobel network
placed from the collector circuit of the input stage to 0V,
and/or having a C or RC across the main gain block within the amp.
Working out the values of the RC components is very tricky.




The effect of the FB will be to flatten the response so vo
at 10 kHz is only a tiny amount down on the 1 kHz level.
The FB has reduced gain at 10 kHz by 31 dB,
and thd will be reduced from say 7% to 0.197%.
The figures are not unusual, but approximate, and don't
allow for the slight errors caused by open loop phase shift.
By 100 kHz, the applied FB has fallen to 10 dB,
and by 300 kHz, the FB stops having any effect on the gain.
The result of declining gain in all amps as F rises makes then stable at high F,
since phase shift increases as F rises, and we don't want gain to be above
1, or 0 dB, if the open loop phase shift has exceeded -180 dregrees.
If you have 180 degrees of phase shift, and more open gain than 1,
Then the amp will oscillate at some HF when FB is applied,
especially if the load is a medium capacitor load, say 0.22 uF,
and there is no zobel network.

Thanks for re-freshing my memory on theory!

It is possible to have wide bandwidth open loop amps,
but the majority of those in the shop have low open loop BW.
They usually measure a lot better than a tube amp.
But this doesn't mean they always sound better,
or that we should always use SS amps.

I use SS for my stereo, tube for my guitars...

Ah, so for guitars, the amp is part of the instrument,
and tube distortions are deliberate, yet musical.

But Wagner sounds awful through a guitar amp......

But through a good hi-fi tube amp, well,
don't be surprised if the tube amp sounds better than your SS.


Patrick Turner.