This synthesiser kit is rare in that it’s still available! Being modular in its construction, apart from making it extremely versatile as a sound generator also means that construction and testing is easier. The PAiA 9700 modular synthesiser contains, 2 VCO’s, 2 VCF’s, 2 VCA’s, 2 AR envelope generators and an ADSR envelope generator. It also contains MIDI processors and comes complete with patch leads.
Oscillator A produces ramp, square, triangle and sine waves, all available on jack outputs, it can also be switched as LFO while oscillator B lacks sine waves. Both oscillators have pulse width modulation but oscillator B also has a knob to control it manually. Oscillator A has a synchronisation input, while oscillator B has an FM modulation input.
Being semi-modular some of the connections are prewired, you can of course break these connections with patch leads, for instance one of the attack/release modulators is by default connected to oscillator B to modulate the pulse width. Also in addition to being triggered like a regular A/R envelope generator it can also be switched to cycle mode so it functions more like a low frequency oscillator LFO.
With the PAiA 9700 you get a tremendous amount of flexibility, as both the A/R modulators will run in cycle mode they work as basic LFO’s, they have LED’s so you can see what’s going on and if you switch oscillator A you end up with 3 LFO’s. In normal mode they function as envelope generators so with the dedicated ADSR you could have 3 envelope generators instead.
This flexibility also continues with the filters, you have 2, both have simultaneous outputs of high, low and band pass, which enables you to interconnect them for all sorts of possibilities. In addition to the normal voltage control of the cut-off frequency you also have the not so normal option of voltage control of the resonance of each filter which opens up even more possibilities
The VCA mixer section also features voltage control of panning so sounds can be moved around in the stereo field. Also worth mentioning is the MIDI to CV converter. This comes with eight individual outputs so you can route MIDI to modulate any of the other control voltage inputs.
It’s pretty clear that a lot of thought has gone into the design of this synthesiser, and that thought is from one or more users rather than a designer who thinks everyone would benefit from a feature! Flexibility is certainly high on the list of anyone wanting a synthesiser, particularly a modular one and the PAiA won’t let you down. Also worth noting is that looking at the circuits and parts, it doesn’t use anything in the sound generating and processing side that is hard to get or likely to be discontinues in the near future, so if you do need spares you should be able to get them for the foreseeable future.
The only downside is that for me being in the United Kingdom, you have to buy directly from the USA, which means the price varies with the exchange rate and you are also liable to pay import duty which will significantly push up the price.