The Polykit X1 DIY Semi-Modular Analog Synthesizer

video upload by Polykit

Follow-up to Prototype of a PATCHABLE analog SYNTHESIZER

"The Polykit X1 - a DIY semi-modular, analog synthesizer. It is based on the voice card I’ve build over the last months. It brings out all parameters of the card and offers a lot of variations through patching.

I've been so happy with the outcome of the voice card for a polyphonic synth that I've build an interface for a single card. It holds jacks for control voltages and signals, pots for all parameters, switches for filter responses, utility circuits and a power supply. It is the first time I used SMD components for all major parts.

You can find all needed files to build one yourself on my GitHub site https://github.com/polykit/polykit-x-...

0:00 - Intro
0:57 - Design Process / SMD
1:46 - Specs of the Voice Card
2:16 - Specs of the Semi Modular Interface
3:00 - Patching Details
8:26 - Other Controls
8:57 - Conclusion

Interface Specs:
• LFO with triangle/square signal
• Utilities: attenuator, buffered multiple, mixer with attenuator
• Power supply
• Inputs/Outputs:
◦ Pitch CV 1V/oct
◦ Gate/trigger
◦ FM
◦ External input
◦ PWM CV
◦ Hard/soft sync
◦ Panning CV
◦ VCA CV
◦ Filter frequency/resonance CV
◦ ADSR output
◦ LFO output
• Control pots:
◦ Mixer level
◦ Fine tuning
◦ PWM
◦ Filter frequency/resonance
◦ Panning left/right
◦ Attenuator
◦ Level input 1
◦ Level input 2
◦ LFO waveform
◦ LFO rate
◦ ADSR parameters
• Switches:
◦ Saw/triangle signal
◦ External input
◦ Filter frequency and resonance modulation by ADSR (also inverted)
◦ Pole mixing filter mode

Voice Card Specs:
• A single oscillator with saw, triangle and pulse output
• Multiple VCAs to blend between different input signals, a main VCA for the envelope and a panning VCA for stereo output
• An additional external input that can be mixed in, eg. a noise signal
• One envelope generator for the VCA. It can also modulate filter frequency and resonance, also with an inverted signal
• A pole mixing multimode filter with 8 filter responses:
◦ 4P LP
◦ 2P LP
◦ 4P HP
◦ 2P HP
◦ 4P BP
◦ 2P BP
◦ 3P AP + 1P LP
◦ 4P N
• There are multiple options two switch and blend between different signals and filter responses
• PWM, FM and synchronization inputs

Music by LOOK MUM NO COMPUTER"