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Adventures in Debugging

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5/12/2000 2:47 AM

Adventures in Debugging

Just thought I'd share with some of you guys my trials and tribulations with my pedal. I'm building a sweet thing, one of the most incredible sounding overdrive/distortions I've ever heard.

My first pcb had some broken traces from my initial debugging, so I etched another one. Put everything back in, except I put the jfets 1-4 in backwards.

No problem, right? Wrong. One of the jfets wasn't working. Sos I check it out with the meter. Q3's voltages were funny. I wasn't getting 0v on Q3's gate, like I should have.

I check out R8, which looks ok. I pull it out, it measures ok on the meter. For some reason, I pull out a fresh resistor (mainly because they're easier to solder in) and pop it in. Voltages look good! I plug it in and it cranks! Sweet, liquid harmonics and chunkin' tight bass notes pour out of my '65 super reverb! For some reason, that resistor had some kind of bad mojo or something.

Ok. Got that done. Now to jam it in the box. It whines like my baby girl at 3 a.m. High pitched oscillations. Looks like I'll have to mount it different, take in a lot of slack from the wires, some of which are crossed. At least I got it working though.

Another thing: Can anyone recommend a real good 9V battery clip? I got some from Rat Shack and they suck, big time. The conductor in there is thin, real thin, and any stress on that thing will pop it off, sure as shit. I want a GOOD 9V clip, with good, LONG leads.

5/12/2000 3:12 AM

Man, I feel your pain. Seriously. Every once in a while circuits just fight you every step of the way. Believe it or not, I had a marathon restling match with a wimpy little Fuzz Face!! Took away whatever effects-building pride I was starting to have. But it cranks now! Does just what its told. Ha! Anyway, try the mouser 9V snaps. I use 12BC092. Its good wire, with 6 inch leads. I threw out my radio shack snaps when I got these because they seemed much tougher. For 8 inch leads go for 12BC002, and for 10 inch leads get 12BC096. That should be long enough, but if you want 12 inch leads, there is always 12BC003! These are regular battery snaps. I'm not sure what you meant by clip, but hope this helps.

Jake

5/12/2000 3:24 AM
Ed Guidry	Yeah, I meant snaps, I just couldn't find the word. I didn't want to confuse anyone with the actual clips that hold the battery in place.

5/12/2000 1:13 PM

FWIW, I could never get this circuit to quit oscillating at a decent volume/drive level when I had it on the breadboard. I just crossed my fingers when I put it on a pcb and boxed it up. Voila! It worked! But I think it has a lot to do with wire length, and keeping input and output signal lines away from each other.

Your problem with R8 may have been a cold solder joint. I had one of those dog me for months with my Shaka 4. I thought it was the MCM switch, then when it out and out failed I dug into the circuit board and found a resistor that was slightly loose.

Doug

5/12/2000 5:55 PM
aron	Things took a turn for the better when I bought a soldering station. About $50 but best investment I made. Solder works really well with the correct heat. Also, having a good tip makes a difference.

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