Fuzz face hums when gtr vol is down

[emerswin]

Built the neg. ground germanium FF from the GGG site. Sounds amazing. Cleans up when I back the volume down. That's cool. When I turn the guitar volume all the way down, it gives off a mighty loud hum, like a horn blowing...not cool. This must be a simple fix...I hope...anyone? Thanks!

[bwanasonic]

Do a search here for PNP/ Neg. ground issues with the Fuzz Face. Some recent reports mention adapter use vs. battery as being a factor. You will also find many reports of neg. ground PNP FF circuits being problematic. I can't say it's a simple fix, but if you have the patience and feel the need for a DC jack is worth the effort, it can be done (from what I've read. I gave up and built mine pos. ground ).

Kerry M

[petemoore]

A regular WWarts AC ripple gets in the FF circuit.
 GEO has a power supply article, the Spyder IIRC that may be of interest.
 PS inversion isn't that hard.
 red battery clip lead V+ goes to the POS Gnd circuit, as does the + side of the 22uf polarized electrolytic.
 That's it, unless you're using polarized *input or *output caps, in which the + side on Any DC blocking caps [input output caps in this case] goes to the toward the circuit side.
 Have a look at a POS GND PNP FF schematic...these caps +'s and V+'s should match that.
 Bipolar caps are not polarity sensative.

[dosmun]

Putting a large cap such as a 220uF across the power raills will usually fix the problem.  If not measure the resistance on the pot when the hum starts and add a resistor slightly larger than your reading in series with the pot.  

There are more fixes if you do a search.

[emerswin]

Thanks for the answers. I'm a begginer to electronics and this is my first pedal, so I'll see if I can't implement some of your suggestions. I forgot to metion that it does the "horn" sound when using a battery, with the power supply(a voodoo labs) it motorboats when I turn the gtr vol down. Otherwise this thing sounds amazing.

[brett]

Hi.  RG Keen, the box guru, has warned of such things.

Nevertheless, I tried a neg ground PNP fuzzface (and easyface) too.  Always got the motorboat.  Never solved it (though I was always using a regulated power supply, never a battery).  With about 50 builds and a reasonable amount of experience, I could hardly believe that I couldn't solve it.  

good luck with it and let us know if you fix it