No, not really off topic…. this is what it’s all about!
Wow, that’s a real old one! This was the SM series mixers that we made in 1969/70/71. I don’t really know where that one came from…. they were all ‘specials’ in those days; we used to tailor the design to suit the application.
Interestingly, it has a PPM so it was probably for speech recording, but it’s odd that it has so many channels…. it’s a bit of a mystery.
I will get Eric the Oracle to look at the pictures; Eric remembers every mixer we ever made (Eric was a founder member/director of the old Alice company).
Regarding the design, I don’t have any circuits from that era, the designs were very simple with a discrete transistor mic amp and equaliser. Some of the early mixers had a single transistor emitter-follower stage after the fader….. but I can’t be any more helpful than that.
I will report back when I know more. 