Troubleshooting a ds-1 keeley mod

[sinisterguy]

Hey everyone,

I modded my ds-1 to keeley specs a few years back and it turned out great. It went by without a hitch save for a few scratches on the paint because I was too lazy to use a socket wrench to tighten the nuts on the pots and switch.

Fast forward a few years and I have a bud that has a ds-1 sitting around doing nothing because it doesn't sound all that great. He mentions that he'd like to try a keeley modded ds-1, hears mine and wants me to mod his too, so I agree. This time I ran into issues. when I wired everything up, the volume knob acted weird (it starts louder than my other ds-1 and doesn't get as loud as the other one), an almost completely unusable tone knob (it barely does anything) and when I turn up the distortion all the way it starts thumping and the distortion gets sputter. Overall the sound is a lot darker this time too.

Now everything in terms of component values are the same this time. The only thing different is that I used poly mylar film caps from tayda instead of metal film and plain old ceramics instead of the silver mica caps it calls for (I ran out of metal film resistors for one of the value changes as well so I used a carbon resistor). In my experience building pedals I've found that there are a lot of things that will affect the sound before the type of capacitors you use, so I figured this wouldn't be a big deal as long as the values are right.

I've triple checked component values, checked for cold solder joints/bridges, reflowed suspicious looking joints. Maybe I'm just tired and missed something obvious, but in the meantime, anyone have any suggestions?

[R.G.]

The most likely thing is you missed something obvious. Task blindness is a real problem.

Try the procedure in "What to do when it doesn't work". This process seems overly simple and picky, but that process of doing measurements by rote and NOT discarding things be cause you already know they're right has proven deadly effective in rooting out issues very much like this one.