I spent 2 years building fuzz pedals wrong before a scope showed me the truth

For the longest time I always put the input capacitor after the volume pot because every online schematic I found did it that way. Then my friend brought over his old Big Muff and we compared them on a scope. Turns out putting the cap before the pot gives way more consistent tone when you roll the volume down. I had no idea I was losing half the bass frequencies the whole time. Has anyone else had that "wait I've been doing this backwards" moment with a simple component placement?

2 comments

2 Comments

charles5081mo ago

The whole input cap before the pot thing is a good example, but here's a twist nobody talks about. What got me was realizing the hard way that the ground trace length between the input jack and the gain stage can make or break your noise floor, especially with high gain pedals. A scope showed me 2 inches of extra ground wire was picking up radio interference like an antenna, which killed my tone way more than any capacitor placement ever did.

roberts.troy1mo ago

My buddy runs a small recording studio and he found the same thing with his patchbay wiring. He spent weeks swapping out capacitors and op-amps chasing a hum, turned out it was a 4 inch ground loop running parallel to a power cable under the floor. Once he rerouted that one wire the noise floor dropped by 15 dB. It's funny how the tiny details everyone skips over can bite you harder than the big fancy mods. Your mileage may vary but I've seen that pattern pop up in all kinds of builds, not just pedals.