Build Your Own Clone Message Board

The 4.7k is for the LED. I think there's a couple different layouts here.

I just did these mods in my big, ever-changing FUZZ. Really nice to play with but my CONTOUR knob seems to just act like a volume boost when I turn it counter-clockwise. Otherwise it sounds better. I can't quite recall the unmodded sound. But more knobs are always cool. The new "bias" along with my other bias from the trimpot create cleaner - fuzzier settings. I say "bias" because i thought it was just a control to increase/decrease low-end.

For me the Contour control just spoilt the fuzz tone, no matter how it was set, so I removed it. The Fulltone Bias control is a good addition (it's just the bass cut mod, but with the advantage of being adjustable).

What I did find with the Fulltone 69 Bias control & an additional Sag control is that you need the 1k resistor instead of the original spec 470 ohm at R3 for extra output volume, otherwise a lot of settings have a volume drop.

It's good to have the real bias control on top as well, instead of the internal trim pot, as in combination with the other controls you can get some wacky sounds.

I fitted mine all inside a standard BYOC size enclosure turned 'landscape' like the Z-Vex pedals, with a row of 5 knobs along the top. (I left out the pointless LED.)

Generally I'm very happy with it, although I realise that for the cost of the BYOC kit & various bits from Small Bear I could almost have bought a Z-Vex Fuzz Factory! Matt

I built the Ultimate Fuzz and added 69 mods. I was not happy with it, even with pricey transistors from Small Bear, until I changed the output cap to .01uf (for some reason a bunch of schematics show .1uf) and the 220 ohm resistor between C3 and the Contour control to 470 ohm. I think those are the stock Fulltone 69 values, because this thing sounds MUCH better this way. I owned a Fulltone unit before, and I think my BYOC pedal is a little closer to that with these changes. Just a suggestion.