A bit uncommon solid stage push pull output stage!

[ELS122]

The output amplifier in a Realistic 8791 car EQ/Amp. Perhaps it's actually made by Alpine... it smells japanese and the switches in front are branded ALPS Japan.
Common emitter to get more voltage swing since they don't have a switch mode booster circuit, probably wasnt even common back in like 1988
The AC coupling from the pull to the push side is a bit odd.

The OPT looks like it's sized for around 10-15watts probably.
It's labeled 400W  Probably more like 100W combined. the front channels use a TA7250BP which lists 23 watts 4 ohms.

[David Hess]

They already had the center tapped transformer, so why not an all silicon NPN or germanium PNP push-pull?

[Kim Christensen]

It's almost like they are using a stock output transformer in "reverse" so they can get more power out of a limited voltage swing. (12V supply rail)
ie: The transistor output stage drives a 1-2 impedance and the 4 side connects to the speaker.