CPU Micron

CPU Micron is a schematic-accurate recreation of the analogue synthesiser voice Roland built into the MC-202 in 1983, made for iPad by Central Processing Unit. Rather than approximating the sound by ear, its DSP is built from the original circuit diagram and the real component values: the CEM3340 oscillator, the IR3109 transconductance filter, the discrete-transistor envelope and the op-amp LFO. Every figure comes from the schematic, from a measurement of a working hardware unit, or from the manufacturer's own service-manual specifications — and where a figure could be both calculated and measured, the two agree. THE VOICE • Oscillator with simultaneous saw and pulse, variable pulse width and PWM, and a 2′ to 16′ footage switch • Sub oscillator one and two octaves down • Four-pole low-pass filter that self-oscillates into a clean sine at the top of the control, reproduced from the real…