The Casio HT-6000 is the highend version of the Casio HT-3000 with aftertouch, 2 jogwheels, 8 x polyphony and 20 lower tones. Next to 40 programmable and storable sounds, 18 drum sounds are on board - combinable with additional variations.
The sound synthesis is a lot more sophisticated and very powerful, because 4 digital controlled oscillators with 64 waveforms are available at once. The first 32 waveforms have the same effect on all 4 oscillators, whereby tone pitches, aftertouch and volume levels can be adjusted flexibly in relation to one another. The remaining 32 waveforms can be combined differently, for example to unleash a fascinating ring modulation or to provide for an extra, adjustable noise oscillator.
The poly filter section is also an analogue construction built with the JRC 2090D chips, but this time, you get 8 (!) of them at once, i. e. a separate filter for each voice. On top, considerably more parameters are at hand and the extra aftertouch can be adjusted for different sections (filter, DCA, tone pitches).
Like on the Casio HT-3000 and the Hohner PK-250, I furnished the resonance and cutoff filter inputs with individual control voltages, which can be adjusted by 2 pots. Due to the 8 modules, this rebuild was a lot more complex and a precise calibration of the filters in relation to one another very time-consuming. Besides, I built in 2 switchable, external CV INs for controlling cutoff and resonance which can now be operated with a MIDI-CV-interface by using sequencer software. I added another 2 switches for sound manipulations that evoke interesting, atmospheric artefacts.
The result was worthwhile, cause where are you going to find a MIDIfied synthesizer with a total of 32 oscillators, 8 x analog poly filter, ring modulation and flexible aftertouch?