The SN76477 is an analog/digital hybrid sound chip released in 1978. The SoftSN Machine provides controls and simulates the analog circuitry including 4 RC oscillators, voltage level inputs and digital inputs around a SN76477 emulator. This provides a fairly accurate reproduction of the real thing in a way that could be built in electronics from 1978 - including the quirks and limitations.
- Input Panel (on left) - Provides v/oct, trig or -5/+5 CV inputs to modulate controls.
- VCO - Adjust frequency of the VCO Oscillator
- Attack/Decay - Adjusts attack and decay phase of 1-Shot triggers. Also provides effects in VCO/Alt mode.
- SLF - Adjust frequency of Super Low Frequency VCO
- Noise - Adjust noise frequency and filter
- One Shot - When envelope mode is 1 Shot, sound is triggered by button/Trig input. Length sets sound duration.
- Duty - Adjusts the duty cycle of the VCO. This can be used to transistion the TRI output to a SAW wave
- Mixers - Selects which oscillators are multiplexed for output
- Envelope - Selects how the mixer performs multiplexing
- OSC - Selects the source for the VCO. SLF modulates the VCO with the SLF.
- TRI output - Provides a TRI wave output which is tapped off the RC capacitor of the VCO. This is a constant output that cannot be controlled by the 1-Shot. It's very erratic based off the SLF frequency. I've added an AGC to the output to adjust the gain.
- SQR output - The multiplexed output of the 3 Oscillators
I welcome Issues and Pull Requests to this repository if you have suggestions for improvement. If you enjoy those modules you can support the development by making a donation. Here's the link: DONATE