DIY PolySynth by Chris Synths

DIY PolySynth In-Progress Demo video upload by Chris Synths

"Hi folks, here's a short, no-talking demo of a prototype 8-voice analog synthesizer I am working on. What do you think?

The hardware of each voice features two VCOs, a ladder-style lowpass and a state-variable highpass filter, wave folder, and ring mod.

All voice circuitry was made with op-amps, OTAs, and discrete components.

There is one effect, an 8-stage analog phaser.

There are two ST microcontrollers for MIDI, voice control, display driving, front panel scanning, etc. Control voltages are produced by 23 DACs, 21 DAC7554 and 2 AD5676.

Circuit design and PCB layout was done in Eagle. PCBs made by JLC. Sheet metal designed in and ordered from emachineshop. Software written in C using STM32CubeIDE. Knobs and buttons are 3D-printed."

Demo of polyphonic analog synthesizer prototype
video upload by Chris Synths

"Some demo sounds from my previous DIY analog synth prototype.

It has six voices, two VCOs per voice, a multimode filter, 3 LFO, 2 ADSR, and a phaser for effects. No Curtis or SSM chips, all discrete and op-amps. A Microchip PIC24 was used for control.

One of the design ideas was to have all the modulation in one place on the panel rather than spread around in each module, but it ended up being not as intuitive to program that way."