This is a quasi-complmentary push pull out put with capacitor coupled outputs. The build quality leaves something to be desired even by 1974? standards. I remember seeing these for sale in a lower Hutt HiFi shop, Butler's Audio, and thinking they looked quite cool but were rather too expensive. I ended up buying a Fountain AF 1250 which was much better built and perhaps a better design? and sounded no worse despite not being boutique. Perreaux picked things up fairly quickly but I'm glad I couldn't afford their early efforts. (Having another look at the GS 2002 the 1221 seems almost a backwards step, mostly the build quality, there is a particle board base and the top cover is crudely folded and attached to the base) There seems to have been a silver face version of the 1221 amp also. I must say this one is still working well with all original parts, it just needed switches and pots cleaned. It uses DIN plugs for both inputs and speaker outputs. The parts are really quite good quality but poor quality components were not really available back in the early 70's. This will get a full recap as simply due to age, over 40 years old; that should improve the sound quality.
Addendum: I have now recapped this amplifier...(all the capacitors were well out of spec) the sound has improved dramatically! detailed mids and highs, very sweet and warm sound; the bass is not full and the volume knob needs to be up quite a long way, it would benefit from using efficient and larger speakers perhaps, but this is definitely a good sounding amp.