Δαφνη Ευτυχια Αρθουρος

[I may of course also be missing a second clue, which would be knowledge of what third, fourth, etc. clues I'm also missing. But I know I'm missing at least one clue.]

I'm fairly certain that I want one of these:

but I've no idea what size transformers to use. (I'm going to plug musical instruments and/or microphones into it, so the big hint for anyone who might be able to guess what transformers go there is: it's an audio-frequency circuit. Uh, and I think guitars, guitar amps, and stomp boxes are hi-Z, right? I expect to need an impedance matching transformer or a pre-amp if I send a microphone signal into it.)

Apparently, this is also a Dalek component, though I don't know whether that'd be this circuit or a digital version of it.

I also want a 'talk box' someday, but this looks waaay cheaper to build and would be fun too.