Dr boogey - Gain knob turned into a 2nd volume knob?!

[ghostsauce]

Couldn't find any similar issues, so lemme pick your brains for a minute. My DB has been working great, aside from an issue with squealing when I turn the gain up over 9 o'clock but I had thought this was due to using an unregulated power supply.. but I took the DB to the church where my big rig is at, used the voodoo labs pedal power to power it, and BOOM-problem. Gain knob functions like a volume knob.  The sound is distorted but in a very different way than I'm used to hearing from this pedal. Doesn't sound necessarily bad, but very very different. So I opened it up and made sure none of the FETs had fallen out, but everything seemed solid.

Brought it home to take a look at it, and the problem is gone again. What the heck?! I was using the same amp both times, even.  I've since tried to find a bad wire or ground issue, but the problem escapes me.

[slacker]

What's the voltage from your unregulated supply when powering the pedal? If it's a few volts more or less than 9 volts, and you've biased the pedal for that supply, then you might need to rebias it to use it with an actual 9 volt supply.

[ghostsauce]

WOW, you were exactly right. The adapter is pumping 18v into it!!!  What a piece of junk.. but I should be able to use a resistor to cut it in half, right?  need coffee before I think about that.

[Seljer]

Using one of the small 7809 regulators would probably be more effective if you play on always powering it from that supply

Or you could rebias it to work on 18V for more headroom

[ghostsauce]

I've already got it biased for 18v, sounds fantastic, but going to 9v sounded like crap. I was more worried I was gonna fry the thing, as well as the xotic rc booster I'm also powering with this adapter... but if it's fine then I like the sound anyways. RC booster sounds better on 9v than 18v, I think. More testing required now that I know what's going on.

[ghostsauce]

Everything I'm reading is saying it's fine as long as the caps are rated high enough.. and since I built both myself I know I always went way over with the cap voltage handling, so given that it's been working this whole time without any real issue I'd say it's probably ok to get by with at service tomorrow, and then I'll take a look next week to be sure.

The only problem I've had has been the Dr boogey squealing if I turn the gain up past 3 with a 500k gain pot, and it's biased for 18v...