analogue polyphonic synthesiser - one built-in vco, vcf, vca, and eg for each of the keys on the keyboard for a total of 48 synthesizer circuits and polyphony! it's vcf has three resonant filters, plus there's a ring modulator, tremolo modulator, and lfo. private collection, non smoking room. all knobs, sliders, and buttons work. needs little servicing due to its old age. please read due to this being a analog synth manufactured in 1970' and used. i'm selling this as is, no warranty, no refunds, no returns. please ask your questions before purchase.