DIY and Pre-Assembled Eurorack Products


The Optodist Development Process In Photo Form

A Blog Post On How The Optodist Was Designed In Detail

The Omnifreq VCO is a Dual VCO with:
- LFO mode
- continuously variabvle shape between sin and tri
- 1V/Oct, PWM, EXPO FM, Sync and X-modulation
- sin/tri, saw and sqr/pulse outs
- LED indicators for VCO/LFO freq/activity 

The Chainsaw Wave Multiplier is a Single/Dual Chainable Wave Mult with:
- either a single set of 1 + 7 stages
- or Dual 1 + 3 stages
- each stage has cv over shift amount and manual shift control
- separate I-III / IV-VI outs 
- ALL stage Output
- separate ins for each of the dual stages
- accepts any waveform input

The Dual Subdivider is a Dual Subharmonic Generator/Clock Divider with:
- either dual 2/4/8/16 outs or
- 2/4/8/16/32/64/128/256 outs
- built in submixer
- Separate inputs for each channel
- invert switch for channel 2

The Dual Dynamic VCA is a unusual VCA with:
- Switchable AC/DC modes
- Separate linear and exponential response with offset/initial knobs
- Input lvl/gain control - actually will boost past 0dB gain
- Velocity response with attenuator - when signal is applied, a larger voltage will push EG response to a wider bell shape, less voltage will result in a taller narrower bell shape response.
- mix out as well as individual outs
- lin control input normalled to expo input for easy patching.
- master initial/offset controls. 

The Envelooper Mod Source is a Quad Looping EG/LFO with:
- 1 Shot/Cycle/Sequence Modes for each
- separate Rise and Fall times
- Normalled Trig inputs to allow easy daisy chaining and simplify patching
- EOC output for each
- LED indicators for Trig in recieved, EOC out high and output activity
- Sequence mode uses End of Cycle to trigger the next in line EG and then wraps back round to the top one in the chain.

Click Here for future Modules and ranges like these   

The idea drawn up by Benjamin Ljunggren that inspired the forthcoming 'Total Stimme' complete voice range:

I decided the voice setup needed a vco, vca, wave multiplier, EG/Lfo modulation source and a subharmonic generator - i.e. a slight change, removing the mixers because the RYO range already contains various mixers and adding some soundshaping that isn't filters since we already have filters in our lineup too. the lack of filters makes it a somewhat west-coast style voice in that there's things that add harmonics such as the wave mult and the subharmonic gen but retains an east coast flavour too since it has a vco, vca & basic eg/lfo mod sources setup.

Below is the Revised and forthcoming Total Stimme Voice Range:


- We are very exited to announce our first collaboration with Jonatan Liljedahl of KYMATICA DEVICES! The 2xVCX Dual Four-Quadrant-Multiplier, VCA and Crossfader module is designed by Kymatica Devices and will be produced and supplied by us at RYO, tune in, multiply, fade out!
- Martin Widmann / widy75 made this great timelapse video of an Optodist build. Check it out!

- A new great video have been published by Ben of this time featuring the 3xVCA. Showing off the perks of it's signal normalling turning this triple linear VCA into a versatile multi response VCA. The normalling is amodification that's installed on all 3xVCA assembled by us and for DIY the modification can be found here.

- The Airtenuator have been featured in Electronic Musician. Thanks for the great article!
- The DrumDokta2 from is soon at your local shop. It features a limited version of Optodist!

- The Ampmix is an easy to build precision 4-channel mixer/attenuator with 2.0x gain and 5.0V offset on each channel in an 8hp module that works well for both CV and audio. It has fully buffered ins and outs that offer a cure for voltage drops when passively multing the outputs and due to output impedance/resistor on not properly buffered outputs. The precision can be upgraded even further as described in the assembly manual.

- Ben from is back with more fun and useful inspiration on how you can use two VC Sequencers and Trig Xpanders.

A Few Archived Photos Mostly From The Old RYO Facebook Page