Help troubleshooting arbiter FF build from scraps

Started by wallofsleep, March 18, 2012, 09:22:21 PM

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wallofsleep

I am attempting to build a silicon arbiter fuzz face from parts I have around. I have had a lot of success building and repairing tube amplifiers but am a novice to pedals. Earlier this week I had a successful Green Ringer build under the same means with virtually no hiccups. Since the fuzz face was the first electronic device I had ever attempted to build, it is stressful to once again potentially fail at the task I had attempted four years ago.

This pedal is built on a perfboard. When I touch the input cable tip, the sound is a loud buzz as though the pedal is working. Touching the output tip generates only loud hum. However, if I am to touch the sleeve of the input cable any sound will quickly disappear. Appropriate buzz will return instantly when I release the sleeve.

I'm considering this possibly a grounding issue, however all grounds are starred to one location.

Standard voltages, second values are with the 8.2k resistor bypassed
Q1
E:   0          0
B: .2AC?    .4
C: 1.75     7.7

Q2
E: 1.13    7.16
B: 1.75    7.7
C: 1.11    7.0



silicon FF schematic from http://fuzzcentral.ssguitar.com/fuzzface.php
The volume potentiometer is omitted at this time. A 1K resistor is substituted for the fuzz potentiometer currently.

LucifersTrip

Quote from: wallofsleep on March 18, 2012, 09:22:21 PM

This pedal is built on a perfboard.

It would be a cool idea to breadboard first and tweak before committing to solder...even experts breadboard first.

Quote
Standard voltages, second values are with the 8.2k resistor bypassed
Q1
E:   0          0
B: .2AC?    .4
C: 1.75     7.7

Q2
E: 1.13    7.16
B: 1.75    7.7
C: 1.11    7.0


these (mainly Q2) are far enough off that it would suggest a mis-wiring/bad or wrong component/transistor mis-orientation.
here's correct voltages:
www.generalguitargadgets.com/pdf/ggg_ff5_instruct.pdf

what transistors did you use?  a clear closeup pic may help someone spot a problem if it is a wiring error.

Quote
The volume potentiometer is omitted at this time. A 1K resistor is substituted for the fuzz potentiometer currently.

do you have it wired like this:
http://fuzzcentral.ssguitar.com/schematics/oneknobfuzz.gif

good luck
always think outside the box