FatMan mod of a mod

[Jeremy N Bradbeer]

Scott Gravenhorst's pitch LFO mod uses 2 caps which can be switched in and out 
with 2 spst switches to get different shapes between square and sine. If you 
swap the 2 caps for 1 cap = to the sum of original 2 (or just wire the 2 caps 
permanently in parallel), and put in a pot (approx. 22k, probably log is best) 
in place of the switches you end up with a continuously variable shape control. 
You can tell if you have the right pot value by soldering the wiper in, setting 
the pot to one extreme and manually making and breaking the connection to the 
far end of the track - if the max. resistance of the pot is insufficent you 
will hear a departure from square wave modulation. To get max. latitude of 
control you need a value that only just gives you a clean square at max. or 
min. rotation (I haven't yet optimized the value myself yet).

No idea if this is soundly based in electronic theory, I just discovered it 
while tinkering around with the original mod.

Jeremy