Vox 847 Wah. Adding True Bypass, LED, and DC Jack ?

[gtrplayr1976]

Hi folks,

A friend is wanting to add a true bypass ,LED ,and DC jack to a Vox 847 wah. Are there any layouts, diagrams, and/or schematics out there ? He has already tried it ,and has it working , it hums with the adapter ,but not with the battery ? Any suggestions are welcome.

Thanks !

[52 Bill]

...it hums with the adapter ,but not with the battery ?

Did he add any sort of power supply decoupling to the circuit? Circuits that were designed to run by battery alone have no power supply filtration built in, so an adapter that has any hum or ripple will make the pedal hum. Has he tried different adapters?

The basic circuit of the V847 is the same as the other wah pedals in the Cry Baby line, so if you look up a schematic for one of those you can see how the adapter circuitry is wired.

[gtrplayr1976]

Did he add any sort of power supply decoupling to the circuit? Circuits that were designed to run by battery alone have no power supply filtration built in, so an adapter that has any hum or ripple will make the pedal hum. Has he tried different adapters?

The basic circuit of the V847 is the same as the other wah pedals in the Cry Baby line, so if you look up a schematic for one of those you can see how the adapter circuitry is wired.

Thanks Bill. I think that is one thing he NEEDS to add. I also found out while searching through many forums that a few things can cause hum. One being if you use a cheap supply they don't filter noise very well ,and another if the supply is too close to the pedal. I'll have him check some of this stuff out.