Ge FuzzFace Clone Issue

Discussion in 'Burnt Fingers DIY Effects' started by Suede, Mar 29, 2013.

  1. Suede

    Suede TDPRI Member

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    I've built a Germanium FFace and although it is supposed to be true-bypass, the dry guitar signal sounds very dull,like a tone filter or a blanket in front of the amp compared to the direct signal.Not really noticing signal loss, but rather a loss in mid-treble frequencies.

    Used this wiring: [​IMG].
    Checked with continuity test with the DMM and the input and output jacks do connect when the pedal is off :? (doesn't this mean it is indeed wired as true-bypass?)
    One other strange thing is that the dullness seems to be worse when the DC adapter is connected, when not it sounds slightly brighter but still filtered..Another thing is that I get some crackles from it here and then but they aren't consistent just come and go.

    I did the mistake to fire it up with the same power supply a negative ground pedal was wired with and got heavy motor sound along with a screeching noise but removed it quickly.I think that if anything got damaged by this though would be the power supply which works fine.

    I'd really like to get this fixed because it's a major bummer and the pedal sounds amazing when on.Any help appreciated! :D
     
  2. steve440

    steve440 Tele-Meister

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    Check all your connections then check them again. With magnifying glass if you have one. Look for stray bits of wire making contact where they shouldn't be

    Steve
     
  3. Suede

    Suede TDPRI Member

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    Thanks Steve!
    Unfortunately this doesn't seem to be the case as I've checked the pedal over and over numerous times.Still I admit I could be missing something.
    I hope I don't come across as an arrogant person,but this isn't one of my first builds,I have my small share of experience in soldering and making analog circuits.
    So my guess would be that this is coming from a design flaw.

    I'm suspecting that the wiring itself isn't true bypass.Any thoughts on this particular drawing?
    The input and output jack might be connected but that doesn't mean the circuit input isn't loaded with the signal.I've noticed that in most suggested 3PDT true-bypass methods,the input or the output of the circuit is grounded in bypass mode.That might be what's missing.
    Any suggestions for a proper true-bypass wiring for a circuit with a positive ground are welcomed of course!

    I'll go back to rewiring the 3PDT and report back hopefully with good news!
     
  4. tjk3052

    tjk3052 Tele-Holic

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    That is true bypass wiring. Grounding the circuit's input during bypass is good practice, but not necessary. If you measure continuity between the input jack and the circuit's input during bypass, then it's obviously wired wrong. Pics would be helpful.
     
  5. Suede

    Suede TDPRI Member

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    The input jack and circuit input do not connect while on bypass mode with continuity test.
    This is what I said:
    I was thinking that in the case of the Fuzz Face with its ridicously simple design and low input impedance,grounding the input could be a possible solution.I'll find a camera tomorrow and post some photos.
     
  6. tjk3052

    tjk3052 Tele-Holic

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    My bad. Impedance doesn't matter though because it's completely bypassed.
     
  7. steve440

    steve440 Tele-Meister

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    Disconnect the cct input, cct output and the led wiring from the switch. See how it works then. You should have bypass and nothing. If your bypassed signal is still bad it's the switch. As Tjk said, the switch wiring diagram is fine. There are other ways of wiring it that will ground the input and help prevent popping but if your using a blue taiwan in a high gain circuit it will likely still pop.
    What schematic are you using for the fuzz cct?

    Steve
     
  8. poiureza

    poiureza Tele-Holic

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    The only possible explanation is that your circuit still connects when in bypass.

    I can only guess that when bypassed, inputs are disconnected but your circuit output still merges with the dry output instead of being disconnected. That would explain the dullness (signal flowing from output back into the circuit and making for some kind of low pass RC filter to ground) and also the behavior with/without adapter (transistors are on/off depending on bias current, so the global RC impedance of the circuit is probably changing).

    Just a guess

    Edit : could be the opposite too (inputs remain connected with outputs being disconnected)
     
  9. Suede

    Suede TDPRI Member

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    I like your explanation,makes sense but using the continuity test shouldn't show the connection between one of the jacks and either the circuit in or circuit out?It doesn't ''beep''!

    It is a blue taiwan but I've added a 1M resistor from circuit input to ground for the pop.
    I used the standard vintage Dallas Arbiter Germanium PNP Fuzzface schematic, except I first built it on a breadboard with trimmers to bias it properly-at least the way it sounded best for me.Then instead of trimmers I used fixed resistors combinations on the circuit board to get the desired values.

    I also added a SPDT switch to select between two input caps for different bass response (one is stock 2,2uF the other one 0,47uF).

    Photos of the pedal:

    [​IMG][​IMG][​IMG][​IMG][​IMG]
     
  10. Armo

    Armo Tele-Holic

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    Why have you 2 connections to the LED and board output throws and why haven't you a stereo input jack socket? Not sure what your trying to do here but I've not seen that before.
     

    Attached Files:

  11. Suede

    Suede TDPRI Member

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    There is no need for a stereo input jack since no battery is used,only dc power supply.

    The LED's anode goes to ground at the input jack's sleeve, while the cathode is connected in series with a resistor (it is inside the heatshrink for insulation) and goes to the 3PDT pin,the way it is shown in the wiring scheme of my first post.When on,it connects with the -9V supply and lights up.

    The circuit output is connected with the volume pot as well.I could had done this on the board but it was more practical for me to do this on the switch.
     
  12. tjk3052

    tjk3052 Tele-Holic

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    No offense, but there are some ugly looking solder joints and melted insulation in your build. Did you try it outside of the enclosure? Try that, making sure there is good separation between wiring and components. Clean up your joints, using a lighted magnifying glass to check your work. Work through the entire circuit checking continuity at each spot. I just recently had to do exactly that and found the problem to be a single strand of wire that was sticking out and making contact with another joint. It was something that I couldn't even see without a magnifying glass.
     
  13. poiureza

    poiureza Tele-Holic

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    Not sure what "beep" means on your DMM

    With both jacks being removed and switch in bypass mode, check the resistance between :
    - input socket hot signal and circuit input
    - output socket hot signal and circuit input
    - input socket hot signal and circuit output
    - output socket hot signal and circuit output
    All 4 should read infinite resistance otherwise it means something remains connected

    Signal could also be leaking through the LED if it's hooked up in some wrong way
     
  14. Suede

    Suede TDPRI Member

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    Beeping happens on continuity mode when two points have the same potential,when they are short-circuited.
     
  15. poiureza

    poiureza Tele-Holic

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    So it means there is some resistance between both points.
    OK but you need infinite resistance to make sure there is no connection at all between both points.
    Can't you measure the Ohms with your DMM ?
     
  16. Suede

    Suede TDPRI Member

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    Thanks for the suggestion!

    It reads infinite resistance to the circuit output but about 1.1MΩ to the input (about 1.07 to be more precise).I guess that is the pulldown resistor (1MΩ) in series with another resistor.
    One other strange observation is that if I measure the resistance between both jacks' tips and the ground (chassis) I get a 64kΩ reading.That should be the in-series resistance that gives me the 1.07 reading.
     
  17. Suede

    Suede TDPRI Member

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    Finally managed to solve the problem!The volume pot wasn't wired in a way that it would be out of the circuit on bypass mode.As a result,the pot was being wired as a resistance between output and ground,sending part of the signal back to the circuit,hence the treble loss and dullness.
    It sounds amazing as it did,but it's not a tone sucker anymore and I can enjoy it!Finally all that search for quality NOS transistors and the effort to bias them pays off!

    Many thanks to everyone here for helping me out with your insight!
    -poiureza you were spot-on with your guess in the end! ;)
     
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