Saturday, September 24, 2011

DIY Fuzz Pedal

More kit love. This one is the B.Y.O.C. extra special vintage fuzz kit which is based on a Fuzz Ace and is available here. This is the second B.Y.O.C. kit I have put together and it was an easy build. The board layout is great and the instructions are easy to follow. One caveat with this kit, however, which is that you need to carefully adjust the bias trimpot to get the pedal to work properly. If you do not you will get a thin sound out of the pedal which may lead you to believe that you have done something wrong in the build, which with me is always the mostly likely cause. In this case I started troubleshooting the pedal before I adjusted the trimpot, which the instructions clearly state that you should do first. In my haste, I thought that I had inserted the germanium transistors incorrectly and in attempting to reseat them (I won't tell you how many times I did this), I broke off one of the leads. Fortunately the kit comes supplied with two SS-9013 transistors for testing and troubleshooting and I am currently running these in the pedal until I buy replacement germanium transistors. You can get these through B.Y.O.C.'s parts store here. The pedal sounds awesome as is and I expect it to sound more awesomer when I get the germanium transistors. I'll update the post when I get around to buying them.

UPDATE (1/2014): I have finally gotten around to sorting out the problems with this pedal. I purchased a second set of AC127 germanium transistors (which were used in the original version [rev 2.0] of the pedal) and later a set of  AC128 germanium transistors (which are used in the new version [rev 3.0 of the pedal), neither of which worked. Meanwhile, B.Y.O.C. came out with a new version of the pedal (rev 3.0), which among other significant differences, has replaced the 0.1uf film capacitor (the yellow capacitor in the photos above) with a 0.01uf film capacitor. I thought swapping out the cap for one with the new value would work, and it did the trick. I ordered a .01uf film cap from Mouser, soldered it in, and the circuit worked as originally intended. The internal bias pot now has plenty of range. I still have not gotten the AC128 transistors to work, but the original AC127 transistors work well. I would recommend making this change if you have rev. 2.0 of the pedal and have had problems getting the germanium transistors to work.

Crybaby GCB-95 True Bypass

If you have an old Crybaby you know that it is a major tone suck when the wah is switched off. It's pretty easy to swap out the original SPST switch with a modern 3PDT switch to mod the pedal to true bypass. Really you only need a 2PDT switch but you can use a 3PDT switch, which seems to be easier to find, and leave one of the rows empty. I bought a couple 3PDT switches from B.Y.O.C.'s parts store here. Instructions and photos for rewiring the pedal are available from Castledine Electronics here. Note that their instructions are for a 2PDT switch. You will have to adapt their instructions for a 3PDT switch (or follow what I did in the photo above). Castledine also has instructions and photos for a couple different revisions of the pedal. In my usual manner of screwing things up as I go along, I originally wired the 3PDT switch the wrong way. As in the photo above the three tabs that make one pole of the switch are aligned vertically ( | | | ) rather than horizontally (- - -). Of course I could have checked this with a multimeter before I wired it up. Oh well. The switch is not at right angles in the photo above because the support for the pot is in the way. You will probably need to swap out washers and nuts until the feel of the switch is right. Combine this with a new pot and your old Crybaby will sound pretty darned good.