[Patrick Turner]

Eeyore wrote:

Andre Jute wrote:

Poopie Stevenson aka Eeyore
wrote:
John Byrns wrote:
Andre Jute wrote:

Historically, the original purpose of Class AB was to annihilate the
second harmonic which before made up such a very large part of the
THD, while still allowing beam tubes and pentodes to give much larger
power than available before.

Andre, why was Class AB necessary to annihilate the second harmonic,
didn't Push Pull operation already annihilate the second harmonic
irrespective of the class of operation?

Yes, you are right. It does.

The SOLE purpose of AB is to produce larger power outputs using the same tubes.

Now this poor dumb slow learner Poopie Stevenson, an embarrassment to
everyone who comes into contact with him, claims to know more than the
RDH4! Yo, Poopie, in the RDH4 (Newnes 1997) on p 545 we find this
nugget of authoritative information by F. Langford-Smith B.Sc. B.E.
himself:

"Class AB operation indicates overbiased conditions, and is used only
in push-pull to balance out the even harmonics."

It's the push-pull that cancels those harmonics YOU UTTER CRETIN ! A Class **A**
push-pull output stage will do that too.

AB operation has NOTHING to do with distortion cancellation.

But it does. There is partial cancelation of 2H currents up until cut
off in one device,
and in each wave of signal voltage.

However, despite the very non linear **currents** in each PP device when
in AB,
the net voltage & current when summed in the load is substantially
linear.

The equivalent circuit of a PP pair is that of two non linear current
generators in series with each end of the
RLa-a. The summed current in Rla-a is linear.

But you can also have PP action and class B where the devices are in
parallel and working on a common load.


There us more than one way to set up devices in PP...

Patrick Turner.


Your problem is that you don't understand what you'r reading so you quote out of
context as a result of your utter IGNORANCE.

Graham