i eventually decided to offer the PS1300 resonator based fonitronik mh21 triple vactrol resonators as a eurorack DIY project.
over the years i sold quite a few of generic PCBs for this project, and the triple bandpass has been well received by many DIYers.
i updated the circuitry in different ways:
the LFO is now resettable (sync)
single inputs
single outputs
switch to invert the LFO for the 3rd bandpass
improved CV response
i will offer a set of PCBs (circuit PCB and front panel components PCB) and a printed eurorack front panel in top notch quality.
the layout would fit the thomas henry DIY projects i offered lately.
prices:
each PCB (circuit PCB or Eurorack adapter PCB) = 7.50 EUR
20HP Eurorack front panel = 15.-EUR
flat rate P&P worldwide: 4.-EUR
(deutschland 2.-EUR)
i will take orders via this thread, PM or email until 16 MAR 15.
PCBs and panel will go into production then.
i expect a lead time of about two weeks.
prototypes have been built and they work well.
download the documentation here:
mh21 Triple Vactrol Resonator Documentation (EuroDIY)


(vactrols and Trimmers mounted on reverse side)

some demo, more to be found on the sme channel:
[video][/video]
https://youtu.be/gCKdcD_EIos