Sequential Circuits Prophet-5: Difference between revisions

The Prophet's eleven oscillators – two per voice and one LFO, are based on the [[CEM 3340CEM3340]] VCO IC, (before Rev 3 the [[SSM 2030SSM2030]]). The IC is scaled at 1V/octave. This means that an overall CV change of 1V ideally produces a pitch change of exactly one octave. So, a CV change of 1/12V (83.3 mV) changes pitch by one semitone.<ref name="techman" /><ref name="mbll" />

The Prophet's five low-pass filters are based on the [[CEM 3320CEM3320]] VCF, (before Rev 3 the [[SSM 2040SSM2040]]). Its scale matches the VCO scale of 1V/OCT, so it is also adjusted in semitones by 83-mV DAC steps.<ref name="techman" /><ref name="mbll" />

The filter and amplifier envelope generators are based on the [[CEM 3310CEM3310]], (before Rev 3 the [[SSM 2050SSM2050]] EG). Its output is a positive DC voltage whose level changes over the time periods set by the input timing CV's. When applied to the VCF and the final VCA the transient voltage determines the frequency and amplitude contours of the voice.<ref name="techman" /><ref name="mbll" />

The voltage controlled amplifiers are based on the [[CA3280]] transconductance op-amp IC (before Rev 3 the [[SSM 2020SSM2020]]).<ref name="techman" />