From mcelhany@u.washington.edu Mon Nov 27 14:12:31 1995 27 Nov 95 16:33:12 +0500 26 Nov 95 03:17:49 +0500 Sat, 25 Nov 95 23:43:09 -0800 Date: Sat, 25 Nov 1995 23:43:09 -0800 (PST) From: michal mcelhany Subject: 303cloning X-Pmflags: 34078848 Fellow hardware hacks, I have had success in cloning a TB303 filter using 2n3906 and 3904 transistors! A few resistance values have to be changed but the overall sound (except for the overdriven VCA) is there! The TB303 "gimmick" as it's called simply seems to spike the incoming CV's, also changing the cutoff at the same time giving a great deepened modulation. This sound is not present on the clones...etc and I wonder if "the gimmick" is patented. Cross modulated VCO's sound great through this filter and if you have the Electronote VC slewer with a .22 charging cap(like the 303) you can make the notes glide into eachother with ease!! a snappy or VC controlled envelope generator also is needed as well as an analog sequencer(which by the way gives accents and the needed studdering pattern). I added the "Gimmick" to Gene Stopp's Moog filter, I haven't tested it yet though. The 303 has a transistor ladder like the Moog's, however the cap's down the center are .033(smaller than Moog) and the bases of the transistors are tied to the collectors. This filter runs off +15 volts fine, with a trimmed +5.333v going to a few sections. After I'm finished modding a little more I'll draw up this filter and it will be available. Ian Stokes