Magnus Modulus debugging

[DaSt]

Hi,

I made that one :

http://tagboardeffects.blogspot.fr/2013/04/magnus-modulus.html

The effect is working as expected BUT it is faintly hissing (hiss is way louder on a lamp amp) and a buzz can be heard all the time when not bypassed. That buzz seems to follow the rate setting, just as the tremolo.

I already looked for the obvious faults without finding any. I suspect a component may be involved but i don't know which one to begin with.

ALso please note that in order to make the tremolo work I had to test 5 different J201. The 4 first do work on another circuit.

Thanks !

EDIT :
Here are the voltages :

NE5532
1 - 4
2 - 3.78
3 - 3.73
4 - 0
5 - 3.97
6 - 4
7 - 4
8 - 9.11

TL062
1 - between 4.45 and 6.6
2 - between 4.45 and 6.6
3 - between 4.45 and 6.6
4 - 0
5 - between 3 and 7
6 - 6.81
7 - between 3 and 7
8 - 9.11

PT2399
1 - 4.96
2 - 2.48
3 - 0
4 - 0
5 - 2.73
6 - 2.48
7 - 0.6
8 - 0.77
9 - 2.48
10 - 2.50
11 - 2.45
12 - 2.48
13 - 2.50
14 - 2.48
15 - 0
16 - 2.50