The instrument
The SPV-355 is a pitch-to-voltage converter with a built-in synthesiser. The analogue expander model came onto the market as a low-cost alternative to the guitar synthesizers of the Roland GR series and can be used with guitars and wind instruments.
Details
The SPV-355 is equipped with two VCOs and a sub-oscillator, VCF, VCA, envelope generator, two audio mixers and a variety of interface sockets. The synthesiser's two monophonic VCOs are switchable across three pitch ranges (4‘, 8’ and 16'), and each VCO can generate saw, square and pulse waves. VCO2 has a footswitch-controlled A/B function that allows its tuning to be shifted by up to plus or minus an octave compared to VCO1. VCO1 has a separate square wave sub-oscillator output and all three outputs are fed into Audio Mixer 1.
The ‘P’ in the title of the P/V synth stands for pitch and the ‘V’ for voltage. The main function is to translate an audio signal from an instrument into control voltages and triggers that can play a CV/gate synthesiser. In the audio mixer, these sound sources can be mixed individually before passing through the 24dB low-pass filter. The filter can be controlled by the envelope, the envelope follower or the pitch follower.
(Source: SoundonSound)