Mutron III, take II

[petemoore]

  Still no sweeping...
    Voltage Readings, case/both jack sleeves/DMM black lead common [Gnd.]
1= 0
2= 0
3= 0
4= -11.34
5=0
6=0
7=0
8= 11.00
LFO Opamp
11.28
2.04
3.25
-11.35
0
9.32
9.70
11.23
 OA#3
1=0
2=0
3=0
4=-11.36
5=0
6=0
7=0
8=11.34
  The ekectrolytic capacitor replacements illicit the same response: singal passes in HP/Lp/BP, no sweeping of the filter though.
  I believe the LED is lit steady. Another R/Led was pushed to the photocells bulb side, it was 'lit', varying signal input didn't change the photon output.
  How do the LED driver opamps pin voltages look to you ?
 

[Le québécois]

singal passes in HP/Lp/BP, no sweeping of the filter though.

The led definitely don't vary the resistor if you don't have sweeping but have output signal in all filter mod. If you have it on breadboard, it's easy to put a DMM in parallel with the 220k associated to each LDR and just measured the resistance while playing. Mine work well and R vary between 50k and 220k. Under constant moderately hard strumming, R is an average between 50K and 220K. This average R will determine the overall frequency of your output sound (generally hi or low depending if it's closer to 50k or to 220k). 
Second, It's easy to put a LED and just look at it while playing. It's should light up with picking strength.

By the way, I read your idea (in a post somewhere on this forum) with the second LED in the LDR associated to a pot to somehow fix the higher resistance limit. In a sense this will decrease the sensitivity of the LDR (your sweeping range would vary between let say 150k and 30k instead of the 220k to 50k mention above). I more or less reached the same thing by lowering the Rx resistor (see geofex schematic) and adding a pot in there. Unfortunately, keep in mind that it also affect the filter frequency response by shifthing the average R value up or down and this not always give desirable frequency output. 

* No idea for the OPAMP but with 9v to the LED you have to increase Rx significantly to turn the LED off.