Need help with Hendrix JHF1 fuzz face input trimpot mod

Started by dwrockdoctor, June 07, 2012, 08:38:57 AM

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joegagan

the fulltone input pot on the 69 fuzz has no ground, if i recall, so this is series resistance. to replicate what a guitar volume pot does, i always ground it on the last lug like a guitar pot. to keep it from going full silent on CCw, you can interrupt this ground connection with a 2k resistor. 
i haven't compared the fulltone method against mine, but i assume you would not get as severe a gain reduction with the fulltone method.
i think i can deduce from your posts that you were doing the fulltone wiring on your trimpot.


don't worry, you would be able to capture the tones you mention with the easyface, but i also agree, build several, see what you like!
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dwrockdoctor

Yeah Joe, I did the fulltone style mod but with the 250k pot instead of 50k. That's interesting about the ground lug, I did notice that the trimpot does react differently in comparison to my guitar volume. I'm pretty happy with how it's behaving atm though but will keep the idea of grounding the lug in mind for future reference, thanks Joe!

CarbonZinc

Quote from: dwrockdoctor on June 07, 2012, 10:08:58 AM
Okay, thank you very much, that is what I am going for.... Getting my bypassed sound the same as the guitar on 10 and then the fuzz face signal is equal to guitar on 8. With the volume and fuzz on the fuzz face up near full I don't think there will be too much of a problem with volume drops etc anyway, I just want that beautiful cleaned up fuzz face overdrive without having to lower my guitar volume every time I engage it.

One more question and please bear with me... Looking at a few basic silicon fuzz face diagrams floating around and looking at the circuit board on my fuzz face, I suspect that the yellow wire is actually the signal input of the circuit as it is the one connecting to the C1 transistor (which all basic silicon fuzz face circuit diagrams I have seen seem to be where the input first hits the circuit board). Here is a picture:



The yellow wire at the right bottom hand of circuit board in the picture is connected to the C1 transistor (2.2uf), would this be the signal input and where I would solder in a trimpot?

Again, thank you for your patience in helping out a complete noob, I am starting to read around and understand more but it's a bit like reading chinese still and could use a helping hand :)





If I may ask, aren't the two shiny things in that pic nearly in the center of the board that look like tiny screw heads, aren't those trimpots? Because I adjusted those on my JH-F1 a few days ago, and it made a world of difference.