Home Forums GuitarPCB Build Support American Fuzz (solved)

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  • #20512
    Matopotato
    Participant

    Hi,

    My first post. I just got the Am Fuzz Rite 60s kit of Das Musikding. I think I have most of the docs understood. It came with the 3PDT WIRING BOARD v5. In the build doc there is talk of R13 and D2 (LED diode) on the main PCB board.

    1. It says D1 on the board, but I am guessing D2 in the text is D1 on the board? (“If you are using one of GuitarPCB’s 3PDT Wiring Boards,  pads S4, S5, S6 and D2 would be ignored and R13 would not be installed.”)
    2. When D1 on the main pcb is not used for the benefit of the D1 on the 3PDT Wiring Board, then the R13 on the main pcb is just left empty. But that resistor goes to CLR location on the 3PDT instead? (“R14 is the current limiting resistor”, but I find not R14 on either board, so I suppose it is same as marked CLR)
    3. I plan to put a 10k trimpot instead so I can dial it in the light, if it if its. Any thoughts against?
    4. The transistors 3x 2N5088) have slightly different hfe values. Should that be considered when selecting which one gets Q1, Q2 and Q3 respectively? Or it does not matter?

    Cheers and thanks in advance

    #20513
    Bruce R
    Moderator

    R13 will not be installed in the main pcb, and the led on the main pub is also not installed. The document is incorrect, as you point out, as the main pub led is D1, not D2. Under “other important notes” section, R14 should read R13. You are once again correct.
    The difference in gain between each transistor is not that critical in this circuit. If you want, you can socket and see if you hear a difference with a different order, but I doubt you’ll hear a difference.

    I would use a 5k trimmer for the CLR if you want to dial it in, unless you really want a very dim LED. Please note that guitar PCB does sell a 3pdt board with a spot for a trimmer, which is a nicer solution. I’m not sure if Musikding sells these or not but they are called  the “vari-brite” 3pdt board. The only thing I would be careful of if you are going to stick a trimmer in the regular 3pdt board is that you do not turn it lower than approximately 1k8. You might be able to go a little bit lower than that but at some point there will not be enough resistance to prevent the LED from burning out. The vari-brite uses a fixed resistor in series with the trimmer to prevent this.

    I’m sure the Barry will update the build document once he reads this.

    #20517
    Matopotato
    Participant

    Many thanks Bruce R for the quick answer 👍

    I agree that I would probably not hear much difference from transistor placement. The were quite close in hfe. I have a parallel project, Rift Octave Fuzz, and that instruction was a bit more detailed.

    I will either put in the stock R for the CLR and LED, or a socket for a fixed and trimpot in series. Will check Musikding as well, although we’re in different countries so order and shipping is a story of its own.

     

    #20518
    Matopotato
    Participant

    There is probably room for socketing the CLR and putting a 1k8 in series with a 5k trimpot. But on second thoughts, it is a one-off tweak for me. I did get a 3k3 for R13 so I can take that for CLR. Might still sock it though. Then I can switch for 1k8 or 4k7 should I want to. Although I find that I get accustomed to bright or dim pedal LEDs before I get annoyed 😁

    #20609
    Matopotato
    Participant

    Switched on. Led working as it should. Bypass works, but no sound. Some touch of static, and tuner after does show something, but silent. Swapped for other pedal, all ok, so not about the setup of rig.

    Will probe through the schema and see what I find, but not quite sure what values to expect from transistor legs… (or the other parts for that matter).

    #20615
    Big O
    Participant

    Regarding Transistor selection, I prefer lower gain transistors in this circuit.  I have tried 2N3904’s, 2N2222’s and S9013’s primarily at Q1 and Q2. I don’t know what I have now, but I adjusted the transistor selection to taste to try to get a slightly more gritty fuzz.  The circuit this pedal is patterned after a pedal that used 2N2222’s and slightly different component values in a couple of places, made by a certain adult kitty baked dough company.

    #20616
    Matopotato
    Participant

    I got 2N5088s with my kit.

    I actually got it working. Had missed a lug on the stomp. But then the drilling and pots had forced me to put pot pins “3 2 1” instead. And in my somewhat clumsy attempt to desolder and wire up a different order i have lost the copper “through” hole. So now it is more like a brick…

    Since English is not my mother tongue, it took a little to decipher, but i got it. “Adult” kind of threw me in a very wrong direction first, but that has to be my own fault.

    Will try scrape up some copper tomorrow or get a new kit…

    #20735
    Billy
    Moderator

    You can bypass the pad you’ve lifted by using a bit of wire

    Which pot is it

    If you look at the schematic you can see what each pad connects to

     

    #20741
    Matopotato
    Participant

    Thanks Billy!

    Both pots. And I tried that as well, but either I did not manage to do it or something else is missing. Tried to troubleshoot, but nothing stood out as obvious.

    So I ordered a new kit and hope to get that right. I will use the failed one for parts after doing a “potential-walk” and comparing them to see if I can figure it out. If I can learn something out of the failed one, it will have given me something at least.

    #20743
    Billy
    Moderator

    Give it another try whilst you wait for your new stuff

    Connect your wires directly to the pot lugs and it should work

    Texture as you can see lug 1 to ground (So just a wire soldered directly to lug 1 and any ground), lug 2 to R9 you’d need to continuity check to make sure you solder to the correct side of R9 you’d want the side that doesn’t connect to Q3 base and lug 3 to C7 side that doesn’t connect to Q2 collector

    Volume lug 1 to ground again, lug 2 to circuit output on 3PDT switch and lug 3 to  C11 side that doesn’t connect to R10

    Doesn’t look great but if it works it doesn’t matter and as you say worth doing it to learn

    #20745
    Matopotato
    Participant

    Thanks Billy, Will try. Unfortunately I already picked some parts, but they are easy to add back. Very good tips, thanks!

    #20749
    Matopotato
    Participant

    About Texture. In the schema I can find lug2 to R9, and lug 3 to C7 but the last one lug 1 seems to be going to C8 rather than ground?

    #20751
    Billy
    Moderator

    Yes you’re correct it does go to C8 my mistake

    #20757
    Matopotato
    Participant

    👍

    #20763
    Matopotato
    Participant

    Again thanks for the ideas and encouraging me to not give up. Today I bypassed all the connections from the two pots onto their respective locations. I did not go to the stomp itself, but to where the board had its out to the stomp. Figured that should be the same thing since the pot was intended for the board originally anyway.

    But no luck this time either. A slight hum or crackle when twisting the knobs. But no sound. So I’ll leave it for now. And go through it later on if I manage the second attempt.

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