I bought the Radiophonic Four a little over a year ago and, to my knowledge, it is the only one that exists. There's something wrong with that, because there should certainly be many more of these in the world (and you should buy one 
). It is simply the best built synth I have ever owned (and I've owned many) and everything about it exudes quality, right down to the jacks, pots, buttons, and the construction of the individual modules. It is also very well laid out and covers so all the bases of analog subtractive synthesis (with a touch of wavefolding). Oh yeah... did I mention that it sounds incredible? I'll share the pictures that STG shared when it was put up for sale last year, because they're far nicer pics than any I've taken. It's a beauty, isn't it?
