Korg 900PS preset monosynth

via this auction

"The synth has great analog sounds and a versatile feature set that provides control over many aspects of the preset tones. There are also three Harmonic switches that let you create sounds of your own using four harmonic slide controls in addition to the other panel controls.

Best of all, in addition to White Noise, the 900PS has Scale Noise, a feature I have not seen on any synth except the Korg 770. This is essentially “pitched” noise. Unlike White Noise, which sounds the same on all keys, Scale Noise follows keyboard pitch, so you can use it to play melodies. It sounds very eerie, and I think it’s one of the synth’s best features – and certainly its most unique."