SOLVED Troubleshooting Maleficent Mids

[oobs]

Just finished the build. The pedal gets power ok, but there is no sound except on a very narrow band of the "Mids" knob (the upper right knob) I get a "farty" sound coming through? The volume knob seems to work or at least when turned to 0 the farty sound goes off. Also the on-on switch works in the upper position but turning it to down position the sound also goes away.

Build went well the only problem was the upper 072 IC's pin number 1 got flooded with solder and I had to spend some extra time with getting it clean again, and I almost lifted the pad because of heating it too long, but to my eye it seemed that there was pad left so I would think it would work. And I exchanged the 5.6k R9 and R10 resistors for 5.1k ones.

Any ideas off the bat that would cause this kind of stuff?

 

[jimilee]

After you check all your components to make sure they’re correct, you definitely need to go back and reflow your solder joints. On the top, I can see all the way through the pad. On the backside, I can see a few pads, too. This fixes 98% of issues in pedal building.

 

[jwin615]

Also make sure that dual pot is insulated and not contacting the center leg of the pot above it

 

[andrewsrea]

Also make sure that dual pot is insulated and not contacting the center leg of the pot above it

That is an important one! My build I used paper tape, because my usual standby of foam tape would not fit. The soldering leads punched though the paper tape, and I went to two layers of black electrical tape instead and that worked. My first test had funky sound because of the shorts on the dual gang pot.

I recommend flush cutting the solder leads of the components on the opposite side of the dual gang pot for the same reason.

 

[giovanni]

I used a piece of cardboard to insulate the pot. That’s definitely a critical issue to consider for this build.

 

[oobs]

Yes thanks a ton guys, it was the insulation of the pot that solved it! A piece of heat shrink tubing cut open and placed between the parts did the trick. Phew.