[sdiy] Questions on Moding the ADV Bass

[Bill Berzinskas]

Hello list.. hope everyone is doing well..    in my endless search for thump, i've built a few drum parts.. the 909 rim, and the ds-7 clone..  fun times..   i'm looking to get started on my kick and snare now..  And working on the bassdrum currently..  A Few questions about the adv bass from midwest analog.. 

1.   Is there a way to adjust the attack of the EG given the current circuit?  or would this require replacing the EG altogether?   i'm thinking it's everything from the diode off the trigger opamp all the way to the 2n3904.. 

2. The 3904/3906 pair, what exactly is that doing?  converting the level for the 3080? 

3.  The 3080 forms the VCA of this correct?  If I wanted to sum another CV source in here, would i have to use a summing amp?  and would this connect into the 2n3904? 

4.  I'll be replacing the VCO as I don't have a 566 available..  since my oscillator would have square output anyway, i want to add a tri/sq mixing facility..  Is this worth the effort? 

5.  What is the sweep?   Looks like the amount of the envelope going to the VCO Pitch CV..  Can someone Confirm..    If i wanted to sum in an lfo for VCO freq, i assume i'd do it where the sweep pot comes into the 180k going to the opamp (add another 100k res going to - side) right? 

6. What is actually generating this "impact" tone?   it looks kind of like an eq circuit to me.. am i missing something? 

Any input would be awesome.. would like to start getting my revised schematic together for breadboarding..   


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