Elektor Formant Analogue Modular Synthesizer

via this auction
via the description:
"An auction for a working modular synthesizer from the 70s featuring -:
2 – VCO (Elektor)
1 – VCF switchable up to 24db/oct (Elektor)
1 – VCA (Elektor)
2 – ADSR Envelope shapers (Elektor)
3 – LFOs with various waveforms (Elektor)
1 – Noise Module (Elektor)
1 – Ring Modulator (Practical Electronics)
1 – Envelope shaper (Practical Electronics)
3 – AC/DC Mixers for signals or voltages (Own Design)
1 – Voltage Inverter Panel (Own Design)
1 – Pre-amp Module (Own Design)
1 – Multiple Jack Panel (Own Design)
1 _ 4 Octave Monophonic Keyboard (Originally a Farfisa K/B)
1 –Power Supply inside the case (Elektor) and a Power Panel (Own Design)

This unit was built by myself in the late 70s and has given excellent results for many years. I have generally used it with a MIDI to CV converter. It produces really fat deep bass tones when used with a sequencer, it can also produce some screaming lead tones. It is also excellent for sound FX and all those weird sounds. The 2 oscillators track very well (1Volt/Oct.), but could do with slight trimming the control voltages. This is only noticeable by a few beat-frequencies when running in unison. As well as a mixed waveform output, there are separate waveform outputs, which all have an open jack plug inserted instead of switches, so you can take different waveforms to different modules. The 24db filter can self oscillate if the ‘Q’ control is increased. The 2 ADSRs decay with slightly different timings, possibly due to tolerances in the components. I have looked at this but can’t find any difference in the component values. This has never been an issue, because I use them for different tasks (1-VCF, 1-VCA). The 3 LFOs are excellent for modulation of many other modules. The noise output is a bit quite, but still works OK. There is also a Differential Amplifier panel, I’m not sure if this works, and it is not wired in anyway.

The system is already internally wired from the 2 VCOs through the VCF to the VCA, so it does not need any cables to get a basic sound out of it.

It also comes with a Practical Electronics 1x16 or 2x8 stage sequencer in a separate cab. I was going to add extra controls during the build but never finished them. (separate triggers out, voltage out level selector switches). In the same case there are various other modules which are not wired in, and I’m not sure if they work or not. There is a 2 channel input module, for audio signals in. A pulse divider, for use with the sequencer. A sequential switch for use with the sequencer. I have all circuits for these units, if you want to get them working again.

It also comes with a Voltage Controlled keyboard taken from a Farfisa organ with the standard V/C panel made by Elektor. The panel works, but the contacts are very hit and miss, so it will need servicing. The wooden top is not fixed in, just placed on top of the contacts.

The whole system comes with the original magazines and extra paperwork for the other modules. These all give full information for building and setting up.

For more Info see link - http://www.elektor.com/magazines/2008/april/formant-synthesizer-(1977).399233.lynkx

A PDF of the construction details - http://www.ftec-audio.com/formant-classic/downloads/ElektorFormantMusicSynthesiser.pdf"