Class A amps

Misunderstanding.

I didn’t mean that you made it up. But Parasound did.

Why? Because class “A/AB” is not a recognized class of amplifier. If you disagree, show me a respected electrical engineering textbook that lists “A/AB.” But don’t show me Parasound marketing material - that’s meaningless.

Lots of amp companies want to be viewed as class A when they are not, and will also use made-up class names that are not recognized. Cambridge Audio uses class XA, for example. Again, made up marketing name.

Either class A or class A/B, and Parasound is class A/B.

Best wishes,

Agreed to greatly disagree

Peace kzk

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I have to say that this moment I do not have any ‘skin’ in this game. However that being said, I have been in the audio game for a very long time.
And in all that time, I have yet to run across an (A/AB) amp!!

Yes we all know about class A amps and we all know about class A/B, but nothing about A/AB class.
How come?

Now you might be right that in the twisted mind of John Curl, him thinking that there is a A/AB class.
But at this time he is just blowing smoke and there is not a class A/AB termination. Maybe Parasound needs some help selling their amps and told Curl to go blow smoke for them, but who actually knows?

If you have ever spoken to Curl then you know from experience that he marches to a totally different drummer…and blatantly so my friends, blatantly so!!!
Good luck with your dream walking…
Someone’s got to tilt at the windmills?

My first tube amp and Class A at that. Also the one and only amp I ever had where rain sounded like rain and not bacon frying.

Nothing impressive to look at but those 25 wpc or whatever still powered my ML Aerius speakers to a place they hadn’t been before in terms of clarity.

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Re-posting this reply to timm, as the article does a fairly decent job of explaining what is Class A. It really is not about the meters . . .

Yes this is an awesome article. Thanks Howard.

Re kzk comments about this thread and class AB amps. I agree with what he says. But do not mind the discussion. :slight_smile:

But more importantly - that killer RCA VHS player!! :slight_smile:

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Going back to the Audio 1986 Annual Equipment Directory (no longer exists)
A number of Class A/AB amps are listed. Among them are:

on Page 173
Athena M1 and M2 Class A/AB
Page 180
Music Reference A/AB
Page 182
Perreaux AMF 1050, 1850, 3150 Class A/AB
Page 184
Rowland research 5 and 7 Class A/AB

Then again in the Audio 1988 Annual Equipment Directory we again find
Class A/AB amplifiers.

On page 175
Aragon 2004, 4004 Class A/AB
Page 192
Octave Research OR1 Class A/AB
PSE Audio Studio IV Class A/AB
Perreaux PMF 5500, 3150, 2350 Class A/AB
Page 197
Jeff Rowland Group…5 and 7 Differential Mode Class A/AB
Page 203
Threshold S1600, S500, S300, S200…Class A/AB

Amazing that the term Class A/AB was utilized in describing amplifier
classes way back 35 years ago…

So no, John Curl was not contriving the term Class A/AB…
Has anyone here hear of Class A/B1 ? or A/BB ? yet there are
amps listed there with just that class of operation…

This is what I was able to dig up…and find it amazing that
some Thresholds are listed as Class A/AB Stasis others
just Stasis.

Just goes to show…

Best wishes all

You noticed. :slight_smile:

Replaced the two body Panasonic player and recorder with the simple RCA. The Panasonic 4-head player cost a relative fortune back in those days. I think Battlestar Gallactica may have been the first thing I watched.

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hthaller…thank you for Pass Labs article …great article.

I guess the point is:

  1. They are not class A
  2. Whatever they are, they are a subset of class A/B, and therefore class A/B amps.

I stand corrected on Parasound making up the term.

But I still submit that they are just a biasing subset of class A/B. Will any electrical engineer dispute that?

It was never argued that they were Class A…
but Class A/AB and yes perhaps a subset

Did you see how 35 years ago Thresholds (Nelson Pass designs) listed as
Class A/AB operation…?

Best wishes friend

I think we are disputing engineering classifications (me) versus marketing labels without an engineering recognized class (you).

In electrical engineering there is no such thing as class A/AB - that’s what I’m contending anyway.

There are any number of methods of biasing class A/B amp, which is what I said many posts ago. I think A/AB is just one of those.

We need a definition of A/AB.

There may well be such a thing, there may not. But we will never know without knowing what it is.

Otherwise this is just a fight over terminology; a paper fight over who is “right.”

It’s an academic dispute anyway and probably not worth spending more time on.

I’m happy to stand corrected if in fact whatever “A/AB” is - is outside of class A/B. But I’d be shocked if that were the case. (30 years since I studied EE though so……)

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It appears it meant something to a number of amplifier designers.

I can hazard a few guesses, but then the argument would be whether my ideas are correct or not. :slight_smile:

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I think this is like a dispute over barnyard animals.

I’m saying for simplicity there are only 3 broad types of barnyard animals - cows (class A), horses (class A/B), and chickens (class D). [yes I know there are both more types of barnyard animals and amplifier classes (I’m a long since pivoted EE and grew up on a farm, ha!), but play along]

I am saying class A/AB is a horse. Maybe a certain type of horse, but a horse nonetheless, and certainly not a cow.

Davida is saying class A/AB isn’t a horse, it’s a Clydesdale. To which I say, it’s still a horse.

In the Pass Labs article leaving Class A …the title says a lot as well. The article…
Seems to indicate leaving Class A for AB…as output increases…

I think Mr Pass is an engineer…and will let it go at that…

Best wishes

I have never seen a single instance of a class A amp that does not revert to AB at some point, including the one I own. Get over it.

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Thank you aangen…well said