For the Formant I have made a Moog ladder filter. This circuit is based on the MiniMoog/Prodigy VCF. The exp converter uses the cheap and widely available transistor array LM3046, and is temperature controlled (luxury!). Optionally the temperature control can be omitted: simply leave out R1 and replace D1 by a wire. Power supply required is +15V and -15V.
The pcb is pin-compatible with the regular Formant VCF. It is a Eurocard (16x10cm) with a DIN41617 connector.
Obtaining the board
If you're interested I can help you to the board at cost price. The pcb costs me Dfl 37,50, which is ca. US$ 22,- (ex. postage). Mail me if you want one.
Last change June 10th 1996