"Micromoogs and Multimoogs have always been adequate for lead lines and noise FX, but they have a "fault" that restricts their ability to deliver bass timbres a'la the classic Minimoog bass. The VCF has a cap on the audio input that provides DC isolation, but it also forms a high pass filter; on the Micro/Multi, the cap is not large enough to allow low frequency components to pass through. This is evident when you observe the change of the pulse waveform on a scope, as you switch the VCO octave from 8' to 32'. This "fault" is easily fixed." [link - be sure to check out the rest of the emusic-diy site for more.] via Jeff
Update via walkathon in the comments:
"FYI, I'm fairly sure this is the same MicroMoog mod that Phil Cirocco once acknowledged on a MusicThing thread with a "I wouldn't do that if I was you" type reply. Did some googling just now and I couldn't find it, but I remember it quite clearly 'cause I was all set to do that mod on my own MM. I held off, though am definitely open to hearing the defense. Is what it is."
If anyone knows more about this, feel free to comment. I might even have it in the archives. I'll take a look when I get a chance.