You'll find them here: https://www.feedbackmodules.com
They offer both completed and DIY versions of their modules, including a recreation of the classic Roland Juno-106 filter. You'll find a list of their current modules with demos captured below for the MATRIXSYNTH archives. Be sure to see their site for pricing and additional details.
FEEDBACK Modules is brought to us by strat-1.
"The 106CHORUS is an accurate recreation in EURORACK format of one of the most sought after choruses, the one from a famous analog polysynth from the eighties."
"The TWO59 is an accurate recreation in EURORACK format of the VCO/LFO section of the most sought after vintage west coast complex oscillator.
Because of the triangle core, the VCO works very well for FM modulation."
"The CP3PLUS is an accurate recreation in EURORACK format of one of the most appreciated vintage modular audio mixers. The specific distortion makes it not only a great summing unit but also a great sound design tool. The included MULTI is a welcome bonus."
"Sound design channel strip based on a famous late seventies small mixer used by many electronic music bands."
"Sound design channel strip based on a famous late eighties small mixer used by many electronic musicians for the TECHNO sound of the nineties."
"Sound design channel strip based on a famous late eighties small mixer used mostly for the well known TB303 distortion sound."
"The SMARTTVERTER is a simple but very effective utility module for scaling the level and polarity of audio and CV signals"