@MikeWaters I see. That AB amplifier is two common emitter which feed the center tap transformer.

I thought of AB amplifiers as push-pull.

I've read this: en.wikipedia.org/wiki/Power_amplifier_classes#Class_AB

There are different subclasses of AB amplifiers. AB1 AB2.

Is it fair to say that principally different topologies of powertrain can be same class?

It's been a looong time since I thought about amplifier classes. :-)

I'm content with just AB until somebody picks an exception with that.

> Oh yes, those numbers. There's A1 A2 AB1 AB2 etc., and these distinctions apply only to valve amplifiers. [from here ]

Ah. I'll take a look at that soon. :)

Ah yes, this is what I remember.

"There's A1 A2 AB1 AB2 etc., and these distinctions apply only to valve amplifiers.The scheme is a simple one, with a "1" indicating that the valve does not draw any grid current, and "2" indicating that the valve output stage grid voltage is being pushed above the 0 volt mark and into a positive grid voltage, causing the grid to draw some current from the preceding driver stage."

I have little experience with solid-state amplifiers, BTW.

@NickAlexeev I mostly use my phone to access SE these days. I suppose I could keep this chat open on a browser tab on my computer. But not 24/7, as Firefox does more than its share of writing to the SSD.

Our computers here run Debian 12.5 KDE Plasma. How many others here use Linux?

We were forced to dump Win7 because it wasted —no exaggeration— hundreds of hours of our time. And we were running a business.

Never again, Micro$oft. :-(

Speaking of AB2 amplifiers, here's the last one that I designed and built:

web.archive.org/web/20180815144637/http://w0btu.com/…