Yamaha CS-40m

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The CS-40m is a duophonic (2-voice) analog synthesizer that was introduced in 1979. Although Yamaha had already conquered polyphony with their legendary 8-voice CS-80, the CS-40m offered a more affordable approach to something other than a mono-synth. It has a semi-compact 44 note (3 1/2 octave) keyboard, 36 knobs, 12 sliders and over a dozen buttons for easy hands-on performance and editing. There are also 20 patches of memory which can be off-loaded to cassette tape.

The CS-40m certainly isn't as phatt as the CS-80. In fact, the CS-40m is more like a 2-voice version of the CS-20m. Like most CS-series synths the CS-40m has two analog oscillators per voice. Triangle, sawtooth, and square (pulse) waveforms are available on each oscillator, plus there is a noise generator. There is also a simple AR (attack/release) envelope generator for each VCO.

The CS-40m has a multi-mode VCF (filter) switchable between lowpass, bandpass, and highpass filtering. Basic filter cutoff and resonance controls are here, but the filter's resonance can't be driven to self-oscillate. It does, however, have its own ADSR envelope generator for nice sweeping filter effects. There is a basic LFO (Low Frequency Modulator) for modulating the VCO, VCF or VCA. All these classic controls and features and sounds... you would expect wood panels... and there are! The CS-40m has been used by Electronic Dream Plant, Sneaker Pimps, Ultravox, Duran Duran, and Vangelis.

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Yamaha CS-40M
ManualDownload the original owner's manual from SoundProgramming.net.


Polyphony - (2-voices) Duophonic
Oscillators - 2 VCO's + noise gen. Triangle, Sawtooth, Square (Pulse) waveforms.
LFO - Waveforms: sine, up-ramp, down-ramp, square, and sample-and-hold.
Filter - multimode: Low-, Band-, High-Pass w/ cutoff, resonance, and ADSR envelope controls
VCA - ADSR (x5 switch)
Arpeg/Seq - None
Effects - None
Keyboard - 44 keys (3 1/2 octaves)
Memory - 20 patches via 2 banks of 10 presets; external cassette interface
Control - CV/Trigger outputs for each voice and CV inputs for portamento, sustain, brilliance, volume and filter.
Date Produced - 1979 - 1986