AC Adapters and Wah Wah Hum

I have a vintage VOX v846 Wah Wah pedal that would hum like crazy if I tried to use an AC adapter to power it. I tried different adapters and even installed a jack so the adapter could plug in. Still it hummed.

A fellow named Geoffrey Teese from Gafney, South Carolina (home of the Peachoid) was an authorized VOX service tech and has posted many great mods and tips for VOX wahs and wahs in general on his website. In the Troubleshooting section I read this:

Q: My wah hums with a power adapter.
A: Most power adapters are poorly filtered, if at all. Even wahs with power filters built-in can hum with some of the power systems out there. Try adding a diode (1N914 is cool) to the adapter jack's "+ power" to the board wire . The "clear glass" end towards the jack, the end with the stripe gets the wire lead. If that is not enough, add a 100uF/25V electrolytic cap between the + (striped) end of the diode and the power jack's negative lug.

Well, why not? I went to Radio Shack and bought the diode and capacitor, got home and wired them in. The hum was gone. Thanks, Geoffrey.

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