
via
this auction
"The Synthetone SX-1000 is an old Italian basic mono-synth. It has a single analog DCO with three waveforms: sawtooth, square, and PWM (Pulse Width Modulation). There is an analog filter (12dB/octave) with cutoff, resonance, and LFO modulation. There is also a simple ADSR envelope for shaping your sounds. In addition there are also white/pink noise generators a glide effect and a vibrato effect. It's known for fairly stable tuning too.
The Jen SX1000 has got to be the most under-appreciated monosynth of the lot! Although it's very simple, it's capable of some really screaming lead sounds and some trully insane bass tones (particularly when PWM is used carefully). It's as solid as a rock and always works a charm, it also never goes out of tune (unlike a lot of it's bargain bin VCO-equipped rivals). And trust me, it sounds about as undigital as you could ever imagine!

The SX-1000 is a monophonic synthesizer with a 3-octave, 37-note, (C-C) keyboard and a black or white front panel (they came in two colors). Also called the "Synthetone", the SX-1000 features a single DCO (digitally controlled oscillator), with a four octave range (32', 16', 8', 4') and three available waveforms, sawtooth, square, and PWM (Pulse Width Modulation). White and pink noise are also available, as well as portamento/glide. The filter is 12dB/octave. There are two ADSR envelope generators and one LFO."