Fuzz Face Silicon Breadboard - Oscillation problem

Started by Barracuda, January 07, 2017, 03:04:14 PM

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Electric Warrior

Quote from: LightSoundGeometry on January 09, 2017, 09:39:33 PM
she was sitting right around -8.77, Q3 is biased over 8 too , its not the 4.5 volt version ..on the final build I added the tagboard 10nF mod  to the input to darken it up a bit

Yeah, that should sound good. Where is Q2 sitting?

LightSoundGeometry

#21
Quote from: Electric Warrior on January 10, 2017, 10:51:54 AM
Quote from: LightSoundGeometry on January 09, 2017, 09:39:33 PM
she was sitting right around -8.77, Q3 is biased over 8 too , its not the 4.5 volt version ..on the final build I added the tagboard 10nF mod  to the input to darken it up a bit

Yeah, that should sound good. Where is Q2 sitting?

I shipped it off already but I think it was right around .1 or very close. This is what I was trying to explain in another thread about the tonebenders, the bias resistors should be fairly close to vintage and the transistors should almost fall right into place ..if you have to bias out so much probably not right bjts and not really a true tb fuzz.  I used all three resistors that the bear threw in and they are very close to the old specs.

might of been a wiring issue ..I forgot how finicky the off board wiring can be since it was quiet as a mouse open and exposed on the BB without issues

didnt mean to hijack the dude thread  , thought kill two birds with one stone. I used to get in trouble for making too many threads on aforum I was on a long time ago so I am scared to open new threads all the time . was not music related forum

any ideas why a RM can be grounded just about anywhere and still work? im guessing it has to do with flow of electrons someplace lol

Electric Warrior

So all your voltages are in the right ballpark. Funny that you needed such a large power filter cap.

Quote from: LightSoundGeometry on January 11, 2017, 01:39:43 PM
This is what I was trying to explain in another thread about the tonebenders, the bias resistors should be fairly close to vintage and the transistors should almost fall right into place ..if you have to bias out so much probably not right bjts and not really a true tb fuzz.  I used all three resistors that the bear threw in and they are very close to the old specs.

You know that Sola Sound adjusted the bias for the OC81D units, don't you? They swapped the 10k on Q1's base and the 47k on Q2's collector for 100ks. That's all it needs, as Q3's bias depends on Q2's collector resistor as well.

About shielded wire: You only need to ground one end for the shield to do its job, but connecting the other end can be all too convenient. You could connect one of the other ends with the switch to grounding the circuit input in bypass.