Car battery polarity

Cant be done without an H bridge and even then you would need one to drive the output pairs

If you dint have access to complementary NPN/PNP you have to have some transformer to spit the phases. And another one to reassemble the output!

At a slightly lower power output, I can offer an EveryReady Skylark portable radio, bought in 1965 for an amazing twelve-and-a-half guineas, a fortune then!

That had two AF117s in the RF stages and the audio was AC127 into an OC81D with a push-pull output pair of OC81 and AC127, capacitor-coupled straight to the speaker from the mid point.

nib

Nonsense, I will look for the circuit to bring you up to date.

There certainly are designs for totem-pole type output stages where the top and bottom transistors are of the same sex.

And you can split the phases on the input with an extra inverting amplifier.

But the only one I've designed like that had both PNP and NPN transistors in the circuit, although not a complementary output pair nor a transformer anywhere.

nib

That is my experience too. Ive built just about every audio design up to the 1970s and the totem pole requires two output transistors and something pretty beefy to drive it unless you use complementary transistors or it's generally not very efficient at low voltage

The vast majority of pre complement designs used transformer as phase splkittters and as output matchers enabling much more to be got out of a pair of PNP output transistors

Only once complementary pairs became way cheaper then the transformers did we switch to the sorts of designs that powered to 70s 'hi fi boom'

Yes that's the concept, it also has a couple of temperature compensation diodes in the output bias chain. The OC22s are biased so there is only a few mA flowing in the quiescent state. I must point out that I had to match the Vbe of both OC22s to within a couple of millivolts on a Tektronix transistor tester.

Then that is not class A, its class B.

The discussion was a bout a claim for single ended class A design.