I never really considered owning an original Moog Model D (mostly because of the costs) but quite often fantasized about modding one. When the Behringer Model D came anlong and some additional hype was generated by leaked schematics, I had gotten one and opened it up before second thoughts had a chance.
With the old schematics of the originals and some pioneering mod descriptions available, this project was a sweet dicovery journey, especially since a couple of fellow geeks tuned in, notably AndyHornblower, to workshop further mods. Nevertheless, I still managed to grill my first unit, but the second one is still going strong and has a favourite place in my rig.
Paraphonic play and modular extensions
On every easy and highly rewarding mod is to have your Boog’s individual VCOs receive V/Oct signals. Although a amore elegant version of this mod would introduce op-amp buffering and some CV ofsett for the normal “main” V/oct input, this can be done without active parts and works well (you just need to switch your octave selector to “Lo” when feeding direct pitch CV to a respective VCO). The sounds you can get are sweet.
Apart from this you can get ripping sync sounds or, using your CVs more subtly, very lively and almost “natural” sounds (electricity is natural, so c’mon…)
Non-destructive modding with passive components
Modding the Boog could just be a great first project in that most of the mods (except for sync) only require you to solder connections and/or passive components to the back of the PCB panel. You can relatively easily install separate VCO outputs, and direct outs and in for filter and vca.
After tinkering with different filter pole outputs, I came across a trick copied form Cykong’s info on SH101 overdrive mods, which resulted in the Boogdrive, distrotion introduced between VCF and VCA, i.e. a deviation from the good old filter-feedback overdive (routing the synth output back into the external filter input). What’s sweet about the Boogdrive is that its sound depends very much on the type and value of capacitor you use and can change from wet and dirty to harsh and clipping by jsut flicking a switch. Here’s a multi track recording with different overdiven Boog lines using this mod:
Expansion Panels DIY and (soon) offered by Banzai
At the end of the guide I have some info on creating a self-made expansion panel for use with Eurorack systems (zero power consumption), yet there is an initiative underway by Banzai from Portland (Oregon) to have some small run of “Bigger D” panels made, which are based on the GS thread linked above (I have no hand in this at all other than having made my guide thingie and given them feedback on some aspects). Here is Banzai’s demonstration of the prototype “Bigger D” panel:
Another sweet and useful DIY circuit was provided by Blackdog59, which enables mulitrigger use when you play the Boog with the (B)Odyssey keyboard.