Keeley Compressor

[MAO]

Built the no trimmer version from the main page, hoping someone that better understands this circuit can help me find my error.

The Sustain pot is acting like a volume control. The Level, Clip and Attack pots seem to be working properly.

Same issue with 2 CA3080s.

The resistance between Q5 E to IC pin 5 rises when turning down the sustain pot from 27k to 514k. At the same time the pedal's volume gets lower until no sound at all when the sustain pot is fully counterclockwise. Sustain pot lug 1 is not connected.

Here are my voltages.

CA3080
1. NC
2. 4.35
3. 4.35
4. 0.0
5. 0.7
6. 3.57
7. 9.2
8. NC

Q1

C 7.03
B 2.52
E 2.12

Q2

C 6.15
B 3.57
E 3.05

Q3

C 9.18
B 0.0
E 0.0

Q4

C 9.18
B 0.0
E 0.0

Q5

C 9.2
B 9.2
E 8.6

I used matched MPSA18 for Q1 & Q2, matched 2N5088s for Q3 & Q4 and 2N5089 for Q5.

Everything else is stock values except I used 1uf monolithic caps rather than tantalums, could this somehow be the issue?

[MAO]

Apparently electrolytic or tantalum are necessary for the indicated polarized 1u caps. Either that or I inadvertently resolved the true culprit when I swapped them out.  

I just replaced the 5 monolithic caps with electrolytics, and now the sustain pot is working as expected. (I was originally thinking the monolithics might be less noisy then standard electrolytics.)

Sounds pretty good with the electrolitics, I wonder if using tantalums for lower noise is just hype?