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Demo Tape Fuzz build question

Started by jonnygreentrees, November 24, 2016, 06:03:20 PM

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jonnygreentrees

Just finished a Demo Tape Fuzz clone on a board from Jed's Peds and weirdly the gain/trim pot does full gain fully clockwise but also fully anticlockwise with different shades of gain in between. Is this normal?

Betty Wont

That's odd. I'm not familiar with that specific project, but that's not how the DTF works. You may have a solder bridge somewhere causing that, or a bum pot.

jonnygreentrees

cool will have a look for solder bridges and try a new pot

juansolo

Definitely not normal. Gain pot behaves as normal, though it only actually gets fuzzy right at the end of it. Also the vol has a HUGE amount of vol on tap. You'll barley turn the thing on and get unity.
Gnomepage - DIY effects library & stuff in the Stompage bit
"I excite very large doom for days" - playpunk

Boba7

Oh yeah you definitely want a 100k log for volume. It has a LOT of volume on tap. The distortion only comes from the opamp.
A beautiful circuit.

jonnygreentrees

can't see any solder bridges, must be a duff pot

Boba7

I've never had a bad pot... Pretty sure it's something else. But you might be right.
I had never heard of thoses pcbs.
He seems to use some Madbean drawn schematics (as seen on the build doc of the Tape fuzz)

Betty Wont

Quote from: Boba7 on November 24, 2016, 10:31:03 PM
I've never had a bad pot... Pretty sure it's something else. But you might be right.
I had never heard of thoses pcbs.
He seems to use some Madbean drawn schematics (as seen on the build doc of the Tape fuzz)
I agree it could be something else, but i have gotten a pot with a bad disc in it that behaved similarly. Its easy enough to test with a meter. I haven't heard of the vendor before either.

jonnygreentrees

just measured the resistance on the pot and I'm getting 03.3 ohm at both ends of the sweep on a 20k pot. Definitely something wrong with the pot