Behringer Model D Mods

During winter break 20/21 I finally found some time to update my oldest project and write an updated Model D Modifications Guide.. The various modifications include reverting the VCO mixer section original style, declicking the Loudness Contour and some things I covered in previous guides, such as VCO hard sync and pitch CV inputs per VCO. Listen to the changes you get from modding the mixer – insane!


Update August 2023

Now, here’s a story that’s half embarrassing – two things happening at once: a) I can play a 2022 Model D Reissue in the shop and finally do some checking (from memory only though) how clicky the VCA is on specific setting, how the mixer overdrives etc… At the same time, a synth enthusiast called Dan, who was doing my mixer mod, emailed in, letting me know that he found a resistor in the Model D where there is none in the original Mini. Kind of the last piece in the puzzle I had totally overlooked….

So, if you do the mixer mod you do not need to cut any traces for the switches or such: simply rewire to the switch middle pins resistors as follows: VCO 1-3 and feedback = 33k and Noise = 11k. Tie these resistors together and then lift C99 from the PCB – put the cathode back into the PCB and connect your VCO mix node to the freely dangling anode of C99. Then bridge R222 (33k) which attenuates the filter input where it shouldn’t. That’s all – no need for VCA input tweaks etc. to bring level up again. As easy as that… as for the rest, see the following guide…

More sound clips and below the list of mods covered in the guide:

Paraphonic play
VCO Hard sync
VCO PHASE RESET ON KEY-ON (first without, then mod switched on)
MOD amount per CV instead of mod wheel
1uf timing cap instead of 10uf
declick (first second without, then with)
Through hole mylar caps1
Through hole mylar caps 2 (NB resonance trimmer not yet adjusted)

Apologies for not providing any further updates/ or pending mod descriptions for this project any longer. I describe many mods here (more than the classic mods for the original), including mistakes and spelling glitches, and feel I rather want to spend time on other synth modding/development projects.