Ljunggren Audio makes Do It Yourself kits for modular synthesisers in Eurorack A-100 compatible format under the name Roll Your Own or RYO.
Optodist, Penta, Aperture, 3xVCA and Ampmix are among RYOs most popular products.
8-step bipolar CV sequencer with voltage controlled stage addressing
Voltage controlled vactrol distortion/overdrive with LED limiter
4-channel mixer/attenuator with 2.0x gain and 5V offset
3-channel bipolar mixer/attenuator with 5V offset (currently out of production)
Trigger/Gate expansion for the RYO VC Sequencer
Dual bi-directional switch with manual tactile or trig/gate controlled switching
Dual discrete resistor-transistor NAND/AND logic gate
Dual discrete resistor-transistor NOR/OR logic gate
Discrete resistor-transistor XNOR/XOR/NOT logic gate
3x linear dc-coupled precision VCAs
Cycling Sequential Switch
Resonant Vactrol VCF/VCA
5-Step Voltage Sequencer
Dual VCA / Crossfader / Four-Quadrant-Multiplier
Dual state-variable filter
Penta