AM8008 SH05 VCO

Overview  This is replica of the VCO in the Roland SH-5 monophonic synthesizer introduced in 1976. This was Roland first serious attempt at a more stable oscillator using a heated expo generator  and fast CA3130 Op Amps, with a separate Op Amp power supply. It was used in the SH-5 as well as the System 100 and has a 5 octave range and 4 waveform as well as a sync facility.

EuroRack Module:   16HP wide
User Manual:          Download PDF

Detailed Description  The AMSynths circuit is close to the original except for a new Tempco based matched transistor pair rather than the obsolete heated uA726 chip, as the exponential generator. This improves warm up time and precision. Original components have been used, along with a few careful upgrades:

  • 1% Polystyrene Capacitors
  • LS312 Matched Transistor Pair
  • Precision 10V reference

The panel design keeps close to the original with a Pitch potentiometer, Range selection from 2′ to 32′, a choice of four wave forms (triangle, sawtooth, square, pulse), modulation depth and pulse width. The VCO derives its frequency from the Doepfer keyboard bus, which can be switched off for a static VCO. We suggest using the VCO in pairs like the Roland SH-5 with the sync facility patched in.

There are five 3.5 mm jack sockets on the base of the front panel:

  • Modulation Input
  • Pulse Width Input
  • Sync In and Out
  • Audio output
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