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  #161   Report Post  
Peter Völpel
 
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Miles O'Neal wrote:

On Fri, 27 Feb 2004 18:45:28 +0000, Fred Nachbaur wrote:

[very sensible response snipped]

It's usually quite obvious from the context whether the "Class A" being
referred to is per the original definition, or in the context of a "class
AB amplifier operating in the class A region."


Well, to you or me. To the average
guy who's still trying to figure out
what the "Class A' hoopla is, and
what it means, and whether he wants
it, it just sounds like *all* amps
are Class A if you don't play them
too loudly, and hence they will all
have that magic. Yikes!


a class AB amplifier can not operate in the class A region.
If it would operate there it would be class A biased

A class AB amplifier on low volume amplifies like a class A
amplifier with 360° conduction angle, but ist still AB biased
and so is operating class AB.
The same amplifier high driven amplifies like a class B amplifier
and ist still operating AB by its biaspoint.

Peter
  #162   Report Post  
Miles O'Neal
 
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On Fri, 27 Feb 2004 00:21:03 -0500, Rich Koerner wrote:

In fact, there are *no* class B amps.


What the hell are you talking about!!!!!!!!!!!!!


Maybe he meant in hi fi and guitar amps.
Obviously they exist in other worlds,
but not in these two, AFAIK.
....
A class B amp


What the hell are you talking about!!!!!!!!!!!!!!!!!!!!


I've wondered a time or two. 8^/

....

Load relationships is not the issue to understanding the class of
operation of the tubes. The role of the load is irrelevant!!!!!!

You simply don't look to the load to identify the class of operation.


Apparently he does. He defines class of operation
by load, THD and, as far as I can tell, POTM. 8^)
....
Such an amp is regarded as class B. Everyone knows there is bugger all
class A power,
and lots of class B power.


Which I found hysterical. Even translating
into his terms, it's just plain silly. I
have a 12W Class A amplifier in my shop at
the moment. I can easily build a 30W Class
A amp from 6L6GCs (know he would claim it
was only 24W).

But again, I suspect he's refering to
hi fi amps, since my 12W and 30W would be
at much higher distortion levels than he
would be willing to tolerate.


[Actual definitions snipped]

Now, start from there, and you will have more here in AGA, who have a
chance of following you.


Or anywhere else there is anyone with much
of a EE background.

Hey! I think I want to define "mu" as "what
the stage circuit gain ought to be". That
way I can make all sorts of observations
about the fools who run their amps at sub-optimal
mu levels. Maybe I'll call that "lu" for "lusers".
8^)

BTW, I'm not casting any aspersions on his
abilities as an amp tech or designer - hifi
or music. And he can be pretty funny when
he wants to. Although he didn't go far
enough in the bit about the Australian pubs.
I think when the celebration gets so intense
the pub burns, they consider it cause for an
even bigger celebration, and go looking for
another pub to "hang" in.

-Miles


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  #163   Report Post  
Miles O'Neal
 
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On Tue, 24 Feb 2004 23:34:47 -0800, lbrty4u wrote:

Well, good for PA, or a muso.
Not for hi-fi. The thd is too high.


WTF is the matter with you? We are talking about guitar amps, hello?


Alas, no.

The original post was about bass guitar amps,
true. But since it was cross-posted to the horribly
misnamed rec.audio.tubes [1], the discussion may be
about guitar amps, it may be about hi fi amps,
it may be about any sort of audio amps, or it
may be about theory, or any combination or
permutation thereof, with probably a few more
categories I haven't thought of at the moment.

We of AGA are demanding precision and context
from those in RAT (things we can't always manage
in AGA alone 8^); let us be precise and contextual
when dealing with them as well.

And in this case, Patrick provided context.

I must say, despite some of the bizarre things
I have seen, this thread has been a real treat,
with lots of good stuff in amongst the odd.

[Not that odd is necessarily bad, but in this
case I believe some of it is detrimental to
communication, and hence to many reading it.]

-Miles

[1] At least, in my limited exposure, it seemed
it should have been called something else.
Perhaps rec.audio.highend.hifi.tubes . 8^)


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  #164   Report Post  
Miles O'Neal
 
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I still haven't seen an answer; perhaps
the question was overlooked, being buried
in another post.

What is a "cadence" amplifier?

-Miles



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  #165   Report Post  
Rich Koerner
 
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roger wrote:

What a ****** you are. Do you ever take your hand off your dick?


Rodger, for the man who started a most informative and lively thread, you seem to be the
one who learned the least.

So, there is some value to trolls.


Regards,

Rich Koerner,
Time Electronics.
http://www.timeelect.com

Specialists in Live Sound FOH Engineering,
Music & Studio Production,
Vintage Instruments, and Tube Amplifiers


  #166   Report Post  
Patrick Turner
 
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Miles O'Neal wrote:

On Fri, 27 Feb 2004 00:21:03 -0500, Rich Koerner wrote:

In fact, there are *no* class B amps.


What the hell are you talking about!!!!!!!!!!!!!


Maybe he meant in hi fi and guitar amps.
Obviously they exist in other worlds,
but not in these two, AFAIK.


I said there were no class B amps.
When I said that, I meant there were none used in audio,
just as there are no class C amps used in audio.
A class B amp has no bias current. the tubes sit there turned off, but on the
brink
of turning on. Any lower bias voltage applied makes them a class C amp.
The crossover Dn is high in such things in audio, so they ain't used.

But where the bias current is allowed to be some low amount,
the PP amp is imediately a class AB amp, but it behaves
with very little class A power, and most is class B.

Rich seems unable to make any sense out of this, and I have given up trying
yo educate the man
into seeing that *all* class AB amps have some small portion of class A power

up to a threhhold where tube cut off occurs, and then for the rest of the
cycle, its class B, and I don't want another stoopid argument over
definitions or class of operation.

My server went down for 2 days last week, and I have missed a few posts, but
Imdoubt I missed much by the look of it.


...
A class B amp


What the hell are you talking about!!!!!!!!!!!!!!!!!!!!


I've wondered a time or two. 8^/

...

Load relationships is not the issue to understanding the class of
operation of the tubes. The role of the load is irrelevant!!!!!!

You simply don't look to the load to identify the class of operation.


Apparently he does. He defines class of operation
by load, THD and, as far as I can tell, POTM. 8^)


The operation of the tubes defines what is the class of operation,
and the class of op is affected by load.
So a class A amp with one value load becomes a class AB amp with a lower
value load.
Or alternatively, a class AB amp with a specified load will become a class
A amp if the load value is raised.

...
Such an amp is regarded as class B. Everyone knows there is bugger all
class A power,
and lots of class B power.


Which I found hysterical. Even translating
into his terms, it's just plain silly. I
have a 12W Class A amplifier in my shop at
the moment. I can easily build a 30W Class
A amp from 6L6GCs (know he would claim it
was only 24W).


One could set up any pair of tubes with low bias current
to make 30 watts, in an AB situation.
The amount of class A power will be quite low.

The thd will be quite low for the first 1/2 watt, but then rapidly
become quite high, which could be fine for a guitar amp,
but not for hi-fi.
For hi-fi we'd use higher bias current, and perhaps
have 12 watts of class A, after which the limit of 24 watts is reached
in class B, and the whole operation from 0.0watts to 24 watts ic called class

AB operation.



But again, I suspect he's refering to
hi fi amps, since my 12W and 30W would be
at much higher distortion levels than he
would be willing to tolerate.


You have not cited working conditions.

But 2 x 6L6 can be used in triode to make 12 watts
of very low distortion class A, with 12 dB of FB,
or 22 watts in tetrode, with 20 dB of FB.

(snip)

Patrick Turner.


  #167   Report Post  
Miles O'Neal
 
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On Sun, 29 Feb 2004 13:33:39 +1100, Patrick Turner wrote:


Rich seems unable to make any sense out of this, and I have given up
trying yo educate the man


Now that's the funniest thing you wrote yet.

into seeing that *all* class AB amps have some small portion of class A
power
up to a threhhold where tube cut off occurs, and then for the rest of the
cycle, its class B, and I don't want another stoopid argument over
definitions or class of operation.


Gotcha. You can redefine anything you
like, any way you like, any time you
like, and if anyone else disagrees with
you, they're stupid.

You sound like a borderline sociopath,
there, Patrick.

You really need to go google for my post
that has "Patrick" and either "Patsy" or
"Patti" in the subject.

because you missed a *lot*.


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  #168   Report Post  
Peter Völpel
 
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Patrick Turner schrieb:

I said there were no class B amps.
When I said that, I meant there were none used in audio,
just as there are no class C amps used in audio.


class B amps were widely used in public address systems


A class B amp has no bias current. the tubes sit there turned off, but on the
brink
of turning on.


class B data for EL34 (by Telefunken):

Ub=800V, Ug2=400V, Ug1 -39V Ia idle 2x25mA, Ia driven 2x91mA

Output power 100W at K=5%


All audio tubes in AM modulators are class B



Any lower bias voltage applied makes them a class C amp.


class C is deep biased to cutoff

example 807 in class B Ug1= 45V, class C -90V


The crossover Dn is high in such things in audio, so they ain't used.

But where the bias current is allowed to be some low amount,
the PP amp is imediately a class AB amp, but it behaves
with very little class A power, and most is class B.


the EL34 bias for class AB is 2x75mA compared to 2x25mA in class B


The operation of the tubes defines what is the class of operation,
and the class of op is affected by load.


no, by the bias-setting

So a class A amp with one value load becomes a class AB amp with a lower
value load.


no,
the class is not changing, only the conduction angle,
the class is defined by construction and bias adjustment

Or alternatively, a class AB amp with a specified load will become a class
A amp if the load value is raised.


amplifier classes are defined by static values, not by dynamic


Peter
  #169   Report Post  
Rich Koerner
 
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Patrick Turner wrote:

Miles O'Neal wrote:

On Fri, 27 Feb 2004 00:21:03 -0500, Rich Koerner wrote:

In fact, there are *no* class B amps.

What the hell are you talking about!!!!!!!!!!!!!


Maybe he meant in hi fi and guitar amps.
Obviously they exist in other worlds,
but not in these two, AFAIK.


I said there were no class B amps.
When I said that, I meant there were none used in audio,
just as there are no class C amps used in audio.
A class B amp has no bias current. the tubes sit there turned off, but on the
brink
of turning on. Any lower bias voltage applied makes them a class C amp.
The crossover Dn is high in such things in audio, so they ain't used.

But where the bias current is allowed to be some low amount,
the PP amp is imediately a class AB amp, but it behaves
with very little class A power, and most is class B.

Rich seems unable to make any sense out of this, and I have given up trying
yo educate the man
into seeing that *all* class AB amps have some small portion of class A power




in summary

I knew all along what you were driving at, but by the confusion of others, it was obvious
your choice of words and terms weren't working for clear explanation.

So far, you're doin better.

You didn't add in the %'s with the loads, and all the rest of the stuff comparing it from
SE to PP, all in the same breath.

You, or someone else had me commenting because of the lack of clarity. I had to point
out, 20 volts across nothing, means NOTHING. 20 volts across 4 ohms, means SOMETHING.

Clarity is a nice thing, when proper terms are used too.

I find it strange that the points of tube "saturation" didn't pop up along the way too.

Still, no one said why the "A" portion, though small, has a reason for being there.

I thought, that would have entered the dialog at some point.

But,...... that's ok. Most have a handle on what's in front of them, and they are doing
ok too.

So, does it really matter.

What really mattered, was that there is simply no comparisons that can be made with the
common configured amplifiers of choice from both camps with respect to the 6550 tubes,
with their operating environments being worlds apart.

There is NO WAY, they can be compared in the same breath.

Just sit a 400-PS or SVT next to your current hot dog Hi-fi amp, and there is NO
comparison.

It's the 400-PS that separates the Tubes, from the Turds!!!!!!

I even test out 6L6 class tubes in a 400-PS.

Here, take a look, http://timeelect.com/test/turd-tester.jpg

Good USA made 6L6-GC's will take the punishment, with a good performance yield.

All the time without plates turning color.

GE's hold up a lot better than any from off shore.

When it comes to putting the squeeze to get the juice out of the tube, I don't play
around.

You audio guys babied the turds for so long now, you have come to think the GE and the
turds are equal, without regard to the differences in the loading windows of the tubes in
question.

Put the GE's in one of your baby machines, and they will out live the turds.

Still, the reference to a 300 watt class A SVT, had me rolling on the floor over here.

SO, what does that say about that post then.



Regards,

Rich Koerner,
Time Electronics.
http://www.timeelect.com

Specialists in Live Sound FOH Engineering,
Music & Studio Production,
Vintage Instruments, and Tube Amplifiers
  #170   Report Post  
Rich Koerner
 
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wrote:

Rich Koerner wrote in message ...

Specifically, where does using this expression, "Bias Current" point your nose.

No where, specifically!!!!!!!!!!!!!!!


Actually Rich, if this were true, we'd be a lot better off with such
an expression. Bias current points us in a half-vast way toward AB2
(or higher) operation, where grids are driven positive & grid current
is drawn, which might be partly characterized as bias current in a
folksy, audiophile kind of way.


I had actually thought of Ip = bias current, but then, looking back, he had this line in
there.

By bias currents, I do mean the idle currents in the electrodes


Why didn't he stay consistant by saying, the following.

"By bias currents, I do mean the *Bias* currents in the electrodes".


I'd still prefer something like,....

Eg1 = -52 bias voltage, Ig1 = zero IDLE current, or Ig2 = 5 ma. IDLE current.

Or, with B+ being 400 volts, for -52 volts of grid bias on G1, this yields zero grid
current on G1, and 5 ma. for G2, etc....

But, that's just me.



IMHO the most silly thing about this
is that it is irrelevant to the original subject and to 99% of all
tube amp concerns on these 2 NG's. AB2 is not used for low-distortion
hi-fi, nor for the normal economically efficient guitar amp. It is
primarily a modulator or old tube PA amp thing. The usual AB2 ckt
requires low-distortion triodes in A driving the finals' grids through
a driver xfmr. AB2 takes a lot of driving power compared to our usual
AB1 because a lot of it is wasted in grid dissipation when the grids
are driven positive, and this is also why a xfmr is usually needed to
handle the driver current, and why it is impossible with the types of
PI ckts we see in most guitar amps, which clip (poop out the driving
signal) when the grid gets up to zero (or thereabouts). I'm sure you
seen this on your scope a thousand times.

The whole deal of class increase is really simple: it is all about
ways for increasing the drive to the tube, to produce more power
without exceeding its dissipation rating, while accepting higher
distortion and other construction issues as a tradeoff. It is the
tube's fixed dissipation rating that drives all of these strategies,
mostly the plate dissipation but the screen as well, sort of like
finding ways to pile up more amps in your shop without raising the
ceiling (plate) or breaking the window (screen). By the time it gets
to C with tubes, we are done with audio because it's gone nonlinear
and its dit-dah or whatever for RF.



LOL, what a trip!!!!!!!!

The life of free electrons in motion is an interesting thing.

Amazing have to can get then march to your commands on a vacuum tube.

I guess there are the many who are very limited in marching tunes.

OK boys, let's all get in formation, and march to the A class tune!!!!!!!

Hey boss, can we learn the new AB1 tune the LOUDER bands are playing!!!!!!!

We're pooped out, and tired of *wasting energy* with all this marching stuff.

Can't we just sit on chairs, and play the new LOUD AB1 tune!!!!!!!!!!!!!!!

You can still be the boss, and direct the music!!!!!

Damn, I've got to get some sleep!!!!!


Have you ever seen or worked on an AB2 guitar amp, Rich?


RONFLMFAO!!!!!!!!!!!!!!!!!!!!

Only when there is a short from G1 to B+ from the beer inside the
amp!!!!!!!!!!!!!!!!!!!!!!


There may or
may not be one out there in the high-pwr catagory, wld make sense.


Hmmmmmmmmmmmm.................!!!!!!!!!!!!!

Maybe one of those WWII Kw tube amps with the tranny's and big bottles were that way.

Only seen one of them in my life when I was in an electronics surplus place when I was in
high school.



Beyond this, the notion that an amp may behave like lower class
because of what it signal may or may not do, is also poppycock. If an
AB1 signal is conducting on both halves for 360 degress at a low
setting, in no way does that make this a "class A mode." Even if it
has not had any cutoff yet, the tube's dissipation is rising, vs real
A mode which is not.


There you go!!!!!!!

I caught that, but from the other direction. Either way, it takes ya to the same place.

The AC and DC characteristics don't line up to meet the definition.

But, I didn't feel like getting into it, after a long day.

LOL, like now.


This heads, not completes, the list of
stiffnecked sins involved in such thinking or terminology, and is why
I got so stiff in my long earlier post, in light of the persistent use
of such poppycock by pompous nincompoops passing it off as
knowledgegrin.


I guess you can understand why I loose it in here sometimes.

No sleep, and intellectual idiocy!!!!!!!!

Bad combination!!!!!!


Remember Steely Dan's "Reelin' In the Years"?


Damn, that reminded me, I have to call Elliott.


Hey DUDE, I LOVE YA!!!!!

I never rolled on the floor Laughing so hard!!!!!

I also know you have chops more than most, from your post.

And, you get the handle on the juice squeezer.

You, I'm sure, having touched upon the basics of what is needed in a 400-PS, and would
have no problem figuring out how that rascal does it's thing.

Yeah, having understanding of dynamic drive, the loading for such, and the effects of
same, escapes most.

BTW, it was fun having the audio high brow stop in with their road show.

Maybe, I should stick my nose in there from time to time, and check it out.

Hey, what the hell, right.

wink

Thanks for the laughs.

You're cool!!!!!

BTW, what do ya play, if I may ask.



Regards,

Rich Koerner,
Time Electronics.
http://www.timeelect.com

Specialists in Live Sound FOH Engineering,
Music & Studio Production,
Vintage Instruments, and Tube Amplifiers


  #171   Report Post  
Rich Koerner
 
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Miles O'Neal wrote:

On Tue, 24 Feb 2004 14:31:12 -0500, James Angelo Ruggieri, P.E. wrote:

For many years and many years past - I worked at what used to be Guitar
Lab on 48th Street in NYC - and came onboard right after DeMarzio left. I
fixed, modified, and designed/built many tube cadence amps


So what is this "cadence" amplifier you keep
refering to?




http://www.ossaudio.com/

Go here and click on cadence on the top of the page.

Scroll down to the tube amp.

That must be it!!!!!!



Regards,

Rich Koerner,
Time Electronics.
http://www.timeelect.com

Specialists in Live Sound FOH Engineering,
Music & Studio Production,
Vintage Instruments, and Tube Amplifiers
  #172   Report Post  
MBarnett
 
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"Miles O'Neal" wrote:

I still haven't seen an answer; perhaps
the question was overlooked, being buried
in another post.

What is a "cadence" amplifier?


Miles, Dood! Search engine seized up on ya? :-) Best I can come up with
is that they're car audio amps. I don't recall seeing your original
question, so I dunno if there was any context beyond the "what is", but
pretty much all of the hits I came up with refer to Cadence Amps or Cadence
Mobile Audio. Interestingly enough, the first hit on "Cadence Amps" was
this:

"Musician's Friend - 1000's of instruments, musical accessories, and more.
We'll match any price on Cadence Amps you find - Free Shipping on orders
$299 or more."

But if you follow the link, you end up at the Musician's Friend search
results page with "We are unable to find exact matches for your search".
Amusing, if you can describe hoodwinking in that way. :-)

Monte


  #173   Report Post  
 
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Rich Koerner wrote in message ...

BTW, what do ya play, if I may ask.


You will be disappointed. :-) After 13 yrs of workingman rock, then
20 more making believe I was Roy Buchannan (which took the first 10 to
master on that bitch of a '52 Tele & a dimed VR), and then a 12 yr
break & 2 amputated/reattached left fingers, I'm now a fledgling
jazzer. I do some acoustic stuff on the side like baroque folk
(Renbourne etc.). I have gotten to the point where I like the idea of
walking into a gig in one trip with a free hand for the door, and no
one to argue with, to tourists who are awed by my feeble, bull****
attempts to play jazz, with and without only a female singer through a
tiny, powerful sandbox & complex music. But I still go crank & wail
with they boys once in awhile to make sure I can still do it. I was
never the best, but guys my age wrote the book on rock ' roll & we
ain't dead yet. :-)
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