True-bypass popping issue with a booster

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load0
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Joined: 30 Apr 2018, 01:46
Location: Moscow

Post by load0 »

Hello. So I have Ibanez TS modded with a dirty booster for repair. My pal asked me to fix a popping issue (critically loud) with a true-bypass switch. So I've tried following approaches:

1) Added 1M pull-down resistors to the input and output of circuit block (then I've realised that there are already in circuit) - no result
2) Added resistors in series with inputs and outputs, about 5K - no result
3) Re-wired 3DPT switch to the "grounded scheme" - with no result (but that's flipped the waveform of the click )
4) Double-checked polarities of caps - with no result
5) Removed the LED - with no result
6) Added 0.1uf film to the input in series - that has eliminated the click completely, but the booster turned into something like an 0.5x attenuator.

P.S. Ibanez TS modded the way that you can make two chains with a two-pos switch:
IN -> BOOSTER -> TS -> OUT
IN -> TS -> BOOSTER -> OUT

So i've tested everything in two positions, and it's given me no result, also.

Don't want to dig into fast-switching approaches, because there is no more room in the pedal enclosure due to lotta mods (ts-9/808, three clipping modes). I think there's a problem with a booster. I'd be very grateful for any tips.
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booster schematic
booster schematic

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Groovenut
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Post by Groovenut »

Sounds like the fet might be leaky and need replaced. damaged gate junction or something the like.

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load0
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Joined: 30 Apr 2018, 01:46
Location: Moscow

Post by load0 »

Groovenut, Thanks. I'm sure that everything is ok with the jfet.

I've rebuilt the booster from scratch using input and output caps and 1to10 source/drain resistors ration, problem was solved (kinda, at least the pop is pretty quiet right now). :D

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