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  1. #1

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    I'm not sure if I should post this here or in the other gear subsection, but I'm sure any builder or tech could help me out.

    Of course I could just take my guitar to a tech...well, actually I can't because everything is closed still. Either way, I want to learn how to do these kinds of things on my own. I have a Loar LH-650. It has an endpin jack. It came with a 4 conductor switchcraft-type endpin. Originally the "Ring" and "Sleeve" terminals were wired together with a single conductor wire and soldered to the back of the pot along with the ground wire from the endpin jack and the ground wire from the pickup and it worked.

    I have a single volume pot, single pickup, and this 4 conductor endpin jack. I've unwired, rewired, unwired, rewired so many times. But I'm still getting this hum. Am I not grounding it properly? Is there a different way that these should be soldered? Should I get a mono endpin jack instead? I've searched and searched the internet and I can't find anything that can help and I'm to the point where I am just SO frustrated. I've gotten it to where the pickup is picking up the strings, but there's still the hum. I know it's a ground problem because when I touch the ground the humming gets a lot quieter. What is the proper way to ground a 4 conductor endpin jack that I am wiring as a mono output jack rather than a stereo or TRS output jack?

    For reference, this is the type of endpin jack I have.
    https://www.fishman.com/wp-content/u...tall-Guide.pdf
    Last edited by broturtel; 05-11-2020 at 02:25 AM.

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  3. #2
    Are your strings grounded? Is there some kind of wire that goes from either the bridge, the tailpiece or touching the strings between the two? This would go to the ground, either that wire that goes onto the outside of the pot or to the endpin directly.
    There are always so many things that can cause a hum. Let's start with this question, we'll go through the list from there.

  4. #3

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    My first guess would be the same as Jimmy's, lack of ground to the strings. With an endpin jack this is normally done by having the jack and the tailpiece in contact with each other, assuming a metal tailpiece. I don't know how your jack is installed, so I can't tell if there is solid contact between the jack and the tailpiece, but there should be. If there isn't, it's possible to use a short piece of wire to get continuity. It's also possible that the other end of the wire from the volume control has come loose. There should be a continuous circuit from the pickup cover to the volume control case, tone control case, and finally the jack. A connection is needed between the cases of the controls. If any of these connections comes loose, hum will result.

  5. #4

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    I realized my Eastman had an ungrounded tailpiece that was causing a buzz. As a temporary fix I cut a short wire, wrapped one end around the endpin jack and the other around the end of the tailpiece. That eliminated the buzz. I’m ashamed to admit that wire is still there, as I haven’t taken the time to do a proper fix.

    Ungrounded strings act as antennas, picking up all the garbage emanating from dimmers, poorly filtered power supplies, etc. so it’s important to ground them.

  6. #5
    Quote Originally Posted by KirkP
    I realized my Eastman had an ungrounded tailpiece that was causing a buzz. As a temporary fix I cut a short wire, wrapped one end around the endpin jack and the other around the end of the tailpiece. That eliminated the buzz. I’m ashamed to admit that wire is still there, as I haven’t taken the time to do a proper fix.

    Ungrounded strings act as antennas, picking up all the garbage emanating from dimmers, poorly filtered power supplies, etc. so it’s important to ground them.
    I have a wire intertwined with the strings just above the tailpiece which is carved wood. I don't even notice it, I'm kind of charmed by it. But boy was it a hummer before I put that in. I just placed the other end between the tailpiece/jack connecting plate and didn't even need to solder.
    There were times I had to shield the underside of the guitar where the pots mounted, and times when coax braided wires helped. But I'm grateful for those times when grounding the strings did the trick.

  7. #6

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    Another way to ground a wooden tailpiece is to use metal tape. You can buy copper tape, or use aluminum duct tape. Put it under the tailpiece, a strip where the strings attach, a strip back to the jack, and it should be good. Then you don't have to replace the wire every time you change strings. But whatever works...

  8. #7
    Hello thank you everyone for your responses. I'm still having a little trouble.

    For starters, I have a metal tailpiece and my endpin jack is in direct contact with my tailpiece. There is and never was a wire that grounded the strings. I'm a little confused on this, btw. From what I read from each of your responses, I should install an extra wire that is touching the strings but is not soldered to anything for the purpose of grounding? I mean, I legit used the same wiring setup as the original installation. That's why I guess I'm so confused.

  9. #8

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    With an endpin jack, there is no need for a separate wire to the tailpiece in most cases, it's grounded by contact with the jack. But the wire(s) from the jack to the pots may be loose at one of the pots. If you have a continuity checker or ohmmeter, check that there is continuity between the pickup case and the strings, as I said above. The post about wire to the strings wasn't about your guitar, but someone else's, and is just a distraction. My best guess is that a wire soldered to the case of one of the pots, which carries the ground, has come loose. If there is no continuity between the pickup and the strings, you need to remove the pots and check the connections. Of course, this assumes that the wiring of the endpin jack is correct and intact, I would double-check that first, because it's the easiest.

  10. #9

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    You may be able to further the diagnosis with an alligator clip or even a straight piece of wire.

    You touch one end to ground on the endpin jack and the other to various things that should be connected to it.

    Like the outside of the pots, which you can access by taking the knobs off. Also, the strings, the tailpiece, the pickups etc.

    If adding the connection eliminates the hum, then just have somebody hold the wire in that position while you play. Or, figure out something more permanent.

    I just looked at the diagram. The switch makes contact to ground the battery when the plug is inserted in the jack, apparently. If you don't have a battery in the system, it shouldn't matter. So, I don't see how the switch could be making the hum.

    caveat: I've been wrong before.

  11. #10

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    With a simple circuit you can use all sheilded wiring and often times you will not even need to ground the strings. If your tailpiece is metal and your strings are in contact with it then your strings are grounded to the tailpiece. Use all shielded wiring in your circuit and ground to the tailpiece and see how that sounds.

  12. #11

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    I have a few questions.

    One, what kind of pickup do you have; is this a single coil or humbucker magnetic pickup? If it is a single coil pickup like a P90, then you have just explained the source of your hum.

    Two, does the hum change as you point the guitar in different directions?

    Three, have you tried wiring this jack as depicted in the upper left-hand corner diagram on the instructions for a passive pick up? You should only have to wire the tip and sleeve connectors, the ring the battery connectors should be just left ignored. Pretend this is a mono jack. You could be getting a ground loop.

    Four, are you certain that the tip is wired to the output lug of the pot and the sleeve is wired to the back of the pot?

  13. #12
    Okay everyone, the problem is fixed! The grounding issue is fixed. Turns out one of the washers was preventing the endpin jack to come all the way through the hole and it wasn't on very well. But as stated above, the strings are grounded by the metal tailpiece being in contact with the endpin jack.

  14. #13
    Quote Originally Posted by broturtel
    Okay everyone, the problem is fixed! ...one of the washers was preventing the endpin jack to come all the way through... the endpin jack.
    Now doesn't that feel great?!! Almost nothing beats the satisfaction of solving a good mystery. That's one of those things that, if you have the instrument in your hands, feel a wiggle in the jack it'd be a reflexive fix, but so easy to miss. Put that one on my diagnostic list at #721. Thanks for presenting us with a problem with a solution. Want to run for office?

  15. #14
    Quote Originally Posted by Jimmy blue note
    Now doesn't that feel great?!! Almost nothing beats the satisfaction of solving a good mystery. That's one of those things that, if you have the instrument in your hands, feel a wiggle in the jack it'd be a reflexive fix, but so easy to miss. Put that one on my diagnostic list at #721. Thanks for presenting us with a problem with a solution. Want to run for office?
    Ahh man, I am SO relieved to have finally solved this. Huge weight off my shoulders!!