Axis Face rev3 Whistling sound

[Sindran]

Hi everybody, this is my first post here...

Just finished building axis face rev 3 (thanks Phillip) and it sounds great!!!   

..But when attack(fuzz)-pot is full and smooth-pot is minimum it makes this whistling feedbacky sound.
I quess that´s not normal?
It works fine if I just turn attack bit down or smooth bit up.

I used really big Nichiden audio caps for the 0.22 and 0.047yF caps, could this be the problem?
I mean the two caps are about the same size as the rest of the circuit...

[phaeton]

The whistling is called oscillation. 

Check out R.G.'s quick rundown of oscillation causes/solutions in a current thread I just started myself about the same issue.  I don't understand the oscillation problem enough to know if it applies to your situation, but my troublesome circuit is similar to a fuzzface.

Hopefully you can figure it out.

Oh, and welcome to the Forum. 

[mikey]

If i remember correctly, I had a similar problem with my af rev3 si when I didnt ground the pots properly.  The grounds arent mentioned in the layout but they are shown in the schematic.  Lugs 1 of attack and level go to ground and lug 3 of smooth is left open.

[Sindran]

If i remember correctly, I had a similar problem with my af rev3 si when I didnt ground the pots properly.  The grounds arent mentioned in the layout but they are shown in the schematic.  Lugs 1 of attack and level go to ground and lug 3 of smooth is left open.

The pots are grounded like you said. But the circuit is not in the box yet. Could this be the problem?

Should the box be grounded?
How about the chassis of the pots, should I ground them?

[mikey]

I didnt ground the chassis of my pots but when I was testing the circuit and had mine out of box it picked up a TON of rf noise.  I could tune into local radio stations by turning the pots and some of the static was brutal.  I'd definitely check if the problem goes away once you have it shielded.