Elektor Formant

Title link takes you to shots via this auction.

Details:
"There is a good chance that you have not seen one of these before. They were all hand-built by enthusiasts to the design which was originally published as a series on monthly articles in Elektor magazine in 1977 and 1978. See Rick Jansen's story of how he built one (no, that is not the one offered for sale here) at link.

This is your chance to get your hands dirty and to learn how analog synthesisers work. All the constructional articles, including theory of operation, circuit diagrams, PCB layouts, and even playing techniques were republished by Elektor in a booklet, a copy of which is included with this item. Also included is a demonstration audio cassette.

The Formant was a very modular design. The one offered for sale here has most of the electronics in one unit, and the 49 key keyboard and keyboard interface is in a separate unit (see photos). This is what you get:

3 x VCOs.
1 x 12 dB/octave VCF.
1 x 24 dB/octave VCF.
3 x ADSRs.
1 x LFO module (3 LFOs).
1 x VCA.
1 x noise module.
1 x COM ( Control and Output Module).
1 x keyboard interface.
2 x ring modulators and one keyboard repeat circuit (not Elektor designs).

The Elektor book also includes a design for a Resonance Filter Module, but the Formant offered for sale here does not have a RFM. To some extent, the 12 dB VCF can be used in place of the RFM. Of course, with the information provided in the book, you could build yourself a RFM. Some of the components used in the Formant would be hard to find now, but there is no problem like that for the ICs used in the RFM.

Some extra inputs have been added to the VCA for the ring modulators. Another added VCA input, together with a switch added to the 12dB VCF, allows the two VCFs to be used either in parallel or in series."

via Loscha.