DS-TEC OS1 Original Syn 1999 - Yellow

The Ds-Tec OS1 Original Syn is a 3 oscillator, analogue, monophonic synthesiser, with digital control tuning the circuits 256 times a second, so you can save and recall presets and it is ready to run and playback as soon as you switch it on.

I bought this extremely rare synth from new and direct from Dr Dai Hitchins, the inventor and manufacturer, back in 1999. It is in perfect working order and in excellent condition.

It features 3 x VCOs, a -24db self-resonating LP VCF, VCA, 2 x ADSRs, LFO, arpeggiator.

The front panel features 3 x small LED screens, a data encoder and 54 buttons to access all the functions

The rear panel has a mains IEC socket, an external audio input, a single output and MIDI In, out & Thru.

But these specs are just the start - read this in depth description from Sound On Sound magazine:

"Each VCO has Coarse Frequency, Fine Frequency, VCO Shape, LFO Depth, Env 1 Depth and Output Level parameters. VCOs 2 and 3 have an additional X‑Mod feature which allows variable cross‑modulation and waveform sync with the other VCOs, while VCOs 1 and 2 can output saw, inverted saw,variable pulse (including square) and modulated pulse (dubbed 'Chorus') waveforms.

It's worth noting that the pulse waveforms are modulated by an additional, 16‑speed LFO per oscillator that that doesn't tie up the main LFO and allows for some animated, full‑bodied effects when all three VCOs are in action.

VCO3 offers all the above waveforms but also provides white noise and can be set to enable the external audio input. This external signal is then available, alongside output from the other VCOs, for processing by the VCF and VCA. All the VCOs will respond to MIDI pitch‑bend and modulation."

The hidden and very special bit here is the pulse waveform modulation - each oscillator has it's own LFO with 16 different speeds and depth of modulation and this alone can sound massive. Add to this a second oscillator slightly detuned using a different pulse width speed and depth, then a third an octave below, add some cross modulation and/or sync, and the results are shatteringly big, deep rich, thunderous sounds - it always makes me smile when I hear this this in full song.

But even using the more recognisable waveforms and simply detuning or tuning to musical intervals and the bass end is astonishing.

The self oscillating filter is also a thing of beauty and can track the keyboard perfectly to give you, in essence, a fourth sound source."

The inventor, Dr Dai Hitchings, said it would be relatively simple to add CV and Gate to the OS1. and, if you wanted, you could also you could also take a split from the filter to a breakout on the back panel and patch across to the external input into the Oscillator 3 signal path to get that Moog Model D feedback sound.

It is a perfect, hidden gem of monophonic analogue synthesis, with a warm, fat analogue sound and a shattering bass end - probably the best sounding bass synth I have ever heard - and though seemingly simple, does things nothing else can. To my ears, it has all the best sounds of every monophonic Moog model ever made, and then some.

I am selling this cherished beastie because I am now more focused on my video and VR production business and it just doesn't get the use it deserves, so it is time to move it on to someone who wants a unique and sonically huge analogue synth that will give them that secret sauce we all look for.

Check out the YouTube video review I made about this very unit some 9 years ago .......