Tube Works Tube Driver (Taiwan) 3 Knob Pedal Troubleshooting (Muddy Output)

Forum dedicated to helping people debug and troubleshoot non-functional pedals or builds. Please use an clear and informative title, indicating circuit and basic problem. Don't forget to mark the issue as fixed if this is the case.
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funkmasterron
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Post by funkmasterron »

Hi there!

I'm troubleshooting a friend's 3 knob tube driver pedal, which isn't outputting any signal when the overdrive switch is engaged.

Does anyone have a schematic for this version of the pedal?

In tracing the circuit, and using other versions of this pedal's schematics the best I can, the signal is making it through both op amp stages and both tube gain stages ok.

There is a resistor/cap network between the final tube output and the final output, where the signal is getting lost. Without a schematic, it is hard to trace this part of the circuit.

The wiring to the circuit board looks hacked together to me (wires seems to connect randomly to certain places, not nice PTH connection points used throughout), but my friend said this pedal used to work fine.

Appreciate any info anyone has in troubleshooting this pedal, and certainly any schematics of this particular pedal.

Thanks!
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Last edited by funkmasterron on 20 Jan 2022, 22:46, edited 1 time in total.

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ppluis0
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Post by ppluis0 »

Hi funkmasterron, and welcome to this forum.

Take a look at schematic posted in the first post of this thread: viewtopic.php?t=1790

The power supply is different (improved), but the remaining diagram is representative of the unit you have to diagnose.

Cheers,
Jose

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funkmasterron
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Post by funkmasterron »

Jose was super helpful, and even provided the attached schematic, which matches my pedal (not all part values but at least circuit topology). After fixing a couple of issues, I am getting the distorted output to the output jack at the correct frequency. All 3 knobs work properly now.

I'm running the pedal with a GT-12AT7 tube.

However, the sound is extremely muddy.

Any ideas?
tubedrvr.gif

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