a) the CEM3328 was specifically designed for the Mirage. b) I would imaginge the best-selling chips would be #1 - 3340 VCO #2 - 3310 EG #3 - 3320 VCF #4 - 3360 VCA #5 - close tie between the 3372 and the 3374 Paul S. /Doug & I have 3 patents together, but they have *nothing* to do with synths :)