Hello. I'm building an Ashbory-type bass guitar. I'm using the ashbory preamp with the addition of an on/off switch. I also detached the LED from the circuit board. On testing the installation i'm getting a hum when the volume is not on full. On full volume everything is fine. Anything below that creates a hum. The hum is removed when touching any of the controls. I think I have everything grounded well, but i'm new at this. Anyone understand such things that can point me in the right direction?
Here is the schematic and close-up pictures of the preamp front & back: Ashbory Bass Schematic
Here is a picture of my installation. I used shielded wire everywhere. **broken link removed**
You probably need to put shield between the sensitive electronics and you. Try a piece of aluminum foil lining the cavity where the amplifier sits. You can insulate the foil by covering it with masking tape or similar.
You could first try grounding the strings, assuming they are metal.
mneary, thanks for the reply. They are not metal strings... they are some sort of poly i think. I have copper shielding tape i could wrap the preamp in, if it's really needed. Does it mean something that the hum isn't there when the volume is on "10" or 0?
Awesome, thanks guys! I did solder to the cases (ooops... acted too fast), so hopefully i didn't hurt the pots too much. I just tested and the hum is gone! Thanks again for your help and time guys!!!