Help with possible wiring problem

ash-s3ash-s3 Frets: 0
edited September 2017 in Making & Modding
Hi all! this is my first post on the forum! I am learning to play the guitar and recently finished my first kit build LP style guitar, after putting it all together i have nasty hum that comes on when i roll the volume pots down but it doesn't go away when they are at 0, also it does go away when i touch anything metal on the guitar. I have plugged another guitar in on the same amp and lead and it doesn't happen at all so i'm guessing its not the house earth or amp thats the problem. All the grounds have been checked for continuity and they all seem fine including the bridge.

Pickups are Seymour Duncan jazz and custom 5, 500k pots and gibson 3 way toggle. 

i will try and put up a picture of the messy wiring and if anyone could shed some light on where i may have gone wrong or why the humming is happening that would be great!

https://farm5.staticflickr.com/4375/36614470533_bd519e7d92_k.jpg%22




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Comments

  • ash-s3ash-s3 Frets: 0
    edited September 2017
  • ICBMICBM Frets: 71963
    Did you wire the volume pots with the pickups connected to the end terminals and the switch to the middle terminals (correct, standard Gibson wiring) or 'independent' AKA 'backwards' wiring, often used on far-east copies, with the switch to the end terminals and the pickups to the middles?

    "Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski

    "Just because I don't care, doesn't mean I don't understand." - Homer Simpson

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  • The pickups are wired to the middle terminals along with the caps and the toggle is wired to the end terminal, would switching these around make a difference?
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  • ICBMICBM Frets: 71963
    Yes.

    'Modern' wiring - move both the pickup and the tone cap to the end terminal, and the switch to the middle.

    '50s' wiring - move the pickup to the end and the switch to the middle leaving the tone cap on the middle.

    "Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski

    "Just because I don't care, doesn't mean I don't understand." - Homer Simpson

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  • Looking at the photograph, I can see where the pickup output cables enter the control cavity. I can see the purple and blue wires that carry the pickup signals to the selector switch. I can see a grey wire grounded to the neck volume pot. (I take this to be the selector switch chassis ground.) The thing that I cannot spot is which wire brings the signal back from the selector switch and directly to the output jack socket.
    Be seeing you.
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  • thanks, i have switched the pickup and switch wires and it worked a treat! whilst the soldering kit is out is there any tonal differences between 50's wiring and modern wiring?
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  • Looking at the photograph, I can see where the pickup output cables enter the control cavity. I can see the purple and blue wires that carry the pickup signals to the selector switch. I can see a grey wire grounded to the neck volume pot. (I take this to be the selector switch chassis ground.) The thing that I cannot spot is which wire brings the signal back from the selector switch and directly to the output jack socket.
    The wire that takes the signal from the selector switch to the output jack is the braided one running the length along the bottom of the control cavity, in hindsight i could have just used the outside of the braided wire to ground the switch instead of the grey cable.
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  • Is the braided screen of the output cable touching any of the metal contact parts of the neck pickup volume pot? (Try moving that cable out from under the NV pot.)
    Be seeing you.
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  • ICBMICBM Frets: 71963
    ash-s3 said:
    thanks, i have switched the pickup and switch wires and it worked a treat! whilst the soldering kit is out is there any tonal differences between 50's wiring and modern wiring?
    Yes - the advantage with 50s is that as you turn the volume control down with the tone fully up, you get less treble roll-off than you would with Modern. The downsides are that the controls become quite interactive - turning down the tone control to lower than the volume then makes the treble loss *worse* as you turn down the volume - and that the tone controls can't be used independently in the middle position. It's just a matter of preference - and it makes no difference when the volumes are up full, contrary to what you sometimes read!

    "Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski

    "Just because I don't care, doesn't mean I don't understand." - Homer Simpson

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  • after moving the cable and switching the pickup and switch cables over it sounds awesome, no more hum and the volume pots work well! Thanks for the help!
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