I might get crapped on for saying this, but it won’t be the first (or last) time, so here goes nothing. To me, and with all that eye-straining SMT ‘stuff’, if you don’t like the pedal the way it is, flip it over and get a different pedal. Mucking about with the surface mount components, if you aren’t super careful and 101% sure of what you are doing, you risk ruining a good pedal. What if you want to put that itsy-bitsy-teeny-weenie resistor back? :doh: A vintage Little Big Muff is easier, but then again you are screwing with a vintage (and collectible) pedal. I don’t see a ‘win’ happening anywhere here, and just one lose-lose after another.

My best guess is the hum is related to how you are powering something. Either the preamp or the MBox. Now the distorted signal is related to how you are ‘sending’ and ‘receiving’ the signal. Check for pad switches, check for mic/line switches. Something will cause a level mismatch and be the culprit.

Since no on else is hazarding a ‘guess’, here goes nothing. As long as the bias potentiometer has enough range, it should work just fine. However, it will still likely be pretty clean. I don’t have much experience with the KT90, but the SVT itself is designed to be pretty clean. Depending on the speaker cabinet you have, this may end up being a clean amp no matter what. Which means an overdrive pedal is the only option.

No. This isn’t an EQ of any sort. It is a basic BJT amplifier, with carefully chosen capacitor values so only the treble frequencies are amplified. The one potentiometer is a standard volume control to adjust the overall level.

Those are chassis mount, and the terminals may not wrap around the board enough. In a pinch you could rig something up, but there could be other ‘problems’. Cheap as Hell, though.

What’s more, the knob may go on and full counter-clockwise may point at high noon! So your ‘zero’ won’t line up. It’s a hassle, and one I am going through right now for a rack-mount mic preamp. I just cannot get the right potentiometers. I am almost to the point of actually playing Dr.Frankenstein and building one potentiometer from a couple of cadavers. I may have to do this because I am after PC mount.

Ouch! The best idea I have on short notice is to measure the enclosure size, and see what Hammond box matches. Something like this;

where you can sacrifice the enclosure, and just use the bottom. As long as the holes line up. Sure, it’ll cost you money, but what other choice do you have? Deltron make the same thing, so check that as well. I am not sure, but can you still get Bud Boxes? I’m just tossing ideas out there.

That’s going to be tough either way. Most of the parts sellers these days aim their wares directly at the tube heads who modify their amplifiers or try and build tweed Deluxe clones. Those vintage EH type pots are used by no one else today. And yours may wrap around the PC board and that makes it even more difficult.
If worse comes to worse, and you really do need a new control (unless it’s physically broken, my success rate is 100% for saving them), something like this;
[img]https://secure.cedist.com/images/inv/R-V80KA-KU.GIF[/img]
could work if you can carefully flatten the one side of the shaft.
That’s all I know. If you do get a source for genuine replacements, please share that information. I’m sure you’d get at least 912 ‘Thank You’ replies.

It is such a simple circuit that even with a slightly better than basic electronics background you should have the problem solved in a short time. Try using the Mole without the back cover attached. Does it work? Then you are shorting something to the ‘chassis’ as you reassemble the unit. If not, then you have a soldering problem or a resistor lead is bent over and shorting the battery B+ to the common ground case (where the B- is connected to). Should be simple, but that’s just my 2¢, so always remember what you paid for this advice.