Check my wiring diagram and help with my ground hum!

Discussion in 'Luthier's Guitar & Bass Technical Discussion' started by rpavich, Jan 5, 2006.

  1. rpavich

    rpavich Member

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    Hi,
    I'm trying to get a ground hum out of my 335 and am getting frustrated! Not to mention pulling the guts out of the bridge PUP hole sucks also...
    I have the torres bluesbucker kit installed (see pic) and have a low level ground hum.
    Can anyone tell me if I've done something wrong? My wires are shown in color. Also notice that torres has the ground wire from the bridge going to one of the tone pots....is that a problem?

    Also notice that the torres kit is "master tone, and master midrange cut" not two separate tone controls.

    Could the wiring scheme itself be the culprit of the humming or is it just my crappy solder joints?
    I saw that someone mentioned using a multimeter; I have one, could I check the grounding with that?

    Help!

    bob

    [​IMG]
     
  2. PanamaCZ

    PanamaCZ Member

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    Bob,

    Your diagram doesn't show the PUP (-), where are they connected to ground?

    Regarding the multi-meter, use the ohm-meter portion of the meter and confirm that you have continuity, i.e., approx. 0 ohms, between each wire end - bridge to switchable tone control ground, each pot ground to pot ground connection, each pot lug connection to the switch, and both switch lugs to output jack. I'd even do this for the wires you didn't solder.

    You will also want to check the resistance (ohm reading) between each red, blue and green wire and ground to make sure thesee are NOT approx. 0 ohms, i.e., you haven't inadvertently introduced a ground to one of your pickup signals. My wild guess is that your problem is probably at or betwen the switch and the output jack or the PUP (-) are "floating" and not solidly grounded.
     
  3. rpavich

    rpavich Member

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    PanamaCZ,
    thanks. I forgot to include the negative PUP wire in the diagram (it's in there now); they are grounded to the pot case that they are connected to.
    Also...do you see a problem with the bridge ground wire going to the tone control instead of the volume pot?

    bob
     
  4. Fishin'Musician

    Fishin'Musician Member

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    It looks like there's possibly a ground loop going on. Try picking one pot and grounding everything (including the bridge) to just that one pot in a star-like pattern.
     
  5. rpavich

    rpavich Member

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    I emailed Torres and they gave me this install instructions. I've asked some questions (in red type)

    Can you help?

    [​IMG]

    bob
     
  6. Fishin'Musician

    Fishin'Musician Member

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    I think that arrow gets grounded to the bridge (string ground).
    It looks like the rest of the grounds go to the side of that push pull pot. (I guess that's what that is).
    I may be wrong, but that's how I see it. I have no idea what those little bubbles are.
     
  7. rpavich

    rpavich Member

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    Fishin,
    I'll give that a try and see how it goes...

    bob
     
  8. 1guitarslinger

    1guitarslinger Member

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    That symbol is the symbol for ground. It's just showing you that that point gets grounded. Ground it to the back of the pot. Do the same with the bridge ground, solder it to the back of one of the pots.

    Not really a ground loop issue there. That is quite common to connect all the pot grounds and other grounds that way in a Gibson (shown in the first diagram). My 57Ri is done that way and is a peach.

    Sounds like everything is not grounded that should be. Double check your wiring, and make certaing the selector switch frame is grounded. Many people mistakingly forget that, or mistake it for a hot connection.

    Also, you have the volume controls wired differently from his diagram. This isolates each pickup control from the other, but may also cause a bit more noise. Check his deiagram again and compare your first posted diagram. The switch and pickups leads are reversed.

    [​IMG]

    Once this is properly done, the backs of all of your pots will be ground so you can solder anything that needs to be grounded (bridge ground etc.) to the back of any of the pots.
     
  9. rpavich

    rpavich Member

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    1guitarslinger,
    Thanks for the good info...I'm thinking that I might have forgotten the selector switch...

    bob
     
  10. 1guitarslinger

    1guitarslinger Member

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    No problem RP.

    Just make certain the rest of the wiring/grounding is in order as well.
     
  11. rpavich

    rpavich Member

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    1guitarslinger,
    Well....I went thru and took ALL of the wiring off of the guitar; mounted the pots and stuff on a cardboard box and resoldered EVERY joint. I assumed that everything was bad and took nothing for granted. I checked every joint with my multimeter when I was done...

    IT WORKS GREAT! NOT A SPEC OF HUM! Thanks for the updated diagram; that helped me a lot...and thanks for the good advice (from everyone). whew what a relief....I'm through sucking electronic parts out of a 335...

    Darn it, Jim, I'm a guitarist not a FLY SURGEON!

    also, It might be an illusion but it seems louder now....could this be possible?
    bob
     
  12. 1guitarslinger

    1guitarslinger Member

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    Excellent. Glad I could help. ;-)
     
  13. tjs

    tjs Senior Member

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    How are you liking the bluesbucker kit? Are the midrange control and switchable tone control slope useful? Do you find that the midrange control colors the tone when full up, or is it pretty transparent?
     

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