OC2 chopped octave build. Questions...

[Morocotopo]

I posted this into the chopped OC2 post, but I think it needs a separate topic.

I made a Boss OC2 according to Ben Milner´s schem:

http://www.aronnelson.com/gallery/main.php/v/Processaurus/OC_2_chopped.gif.html?g2_imageViewsIndex=1

It´s a simplified Boss OC2. I made my own layout for this, just testing it, works OK, but when feeding a distorted amp, I can hear a quiet "rrrrrrr" in the background. Into a clean amp it´s not audible.The octave pot controls it, when lowered from max it almost dissapears. What do you think? Just to know if it´s par for the course or I should start debugging. Tried a buffer before it but no change. Moving wires around made no difference.
Other issues: On sustained notes, it jumps from octave to octave semi-randomly (not all the time...sometimes). Feature or malfunction? Also, The pots are connected to DC (Vref), so when turned, they make scratching noises... do yours do that too? Do you know if the original did it too? it stikes me as weird...

Other things: The original has a 2SK30 as the fet, I used a J201... will try the 2SK30 later.

Thanks.

[maarten]

I used 2n3819's and experienced no problems: no jumping, no scratching pots. Sometimes I can hear a very very small rattling sound when the octave is engaged and when playing just one single note.
Maarten

[Morocotopo]

I have some 3819´s i think, I´ll try those...I don´t really understand how this circuit works, so it´s a bit of a blind search for me. Maybe today after work. Time to start debugging.

[Morocotopo]

Ok, I tried different FET´s but no change. Now, I looked at the original Boss schem/layout, and it uses all TL022 opamps, those are low current ones, so maybe the problem comes from the quad opamp´s higher current consumption? Especially the LM324,that outputs a square wave I think? Also, I discovered that when touching the diode(s) attached to the 324 the "rrrr" stops. What next? I´ll see...