Single conductor hum to go oop

Discussion in 'Tele-Technical' started by acer, Oct 18, 2019.

  1. acer

    acer TDPRI Member

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    Hi guys, I want to wire minihum for my tele to have oop sound w/ pp pot but just realised that it's a single conductor pup, I know I could open it up and isolate the braided wire with shrink tube and wire that to the switch. What's not clear to me is that if I do that does it mean that the shield won't have ground? Can I add an extra ground wire for the cover and go straight to ground? I'm just not familiar with the internal construction of humbuckers.. thanks in advance for anyone who chimes in..
     
  2. moosie

    moosie Doctor of Teleocity Ad Free Member

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    Converting a 'single-lead' humbucker to a four-wire is tricky, and it's easy to ruin the pickup. The 'single-lead' is actually two: hot, which is the start of one coil, and common, which is the end of the other coil. The other two wires are connected togther internally, forming a series connection. The common is the metal braid, and it also doubles as shield for the hot.

    A four-wire pickup actually has five wires. The fifth is usually bare, and it's the shield, or ground wire, connecting the frame to ground. No matter how you switch the pickup, this always must be grounded. Whether or not it just shields the frame, or also the hot lead, is up to you. When you convert, I recommend using a typical modern style four-wire humbucker shielded lead. It's got the four wires, each with their own inusulation against shorting (but not noise), plus the fifth bare wire, connected to the frame on one end, and ground on the other. The whole mess is wrapped in a conductive mylar sheath, which is the noise shield. It's grounded implictly by touching the bare wire inside the wrap. Then the outer layer of black rubbery insulation protects the whole assembly.

    You'll dissect the pickup, and hook up leads to each of the four coil-end wires. Then solder the bare wire to the frame. On the other end, connect your four wires as needed for your circuit, and the bare to ground.

    Be advised that you'll no longer have hum cancelling when out of phase. The only way to achieve this is to physically flip the magnets in one coil.

    Here's a good article about phase, polarity, and hum: https://www.electricherald.com/guitar-phase-switching/
     
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  3. acer

    acer TDPRI Member

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    Hi, thanks a lot for your thorough reply so in my case I would only need to separate the shield/bare wire to go straight to ground and then put on the heat shrink tube over the braided lead to use that only for +/- right?

    Should I be concerned about not having hum cancelling when switch phase? Or is is a common trade off that you can live with?
     
  4. moosie

    moosie Doctor of Teleocity Ad Free Member

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    You might not like the noise when OOP, but there's no way around it. Obviously some people don't mind...


    No....

    You currently have one shielded lead. Hot connects to one coil end, and braid connects to the other coil, opposite end. Open the pickup, and find where the two coils are connected. Cut that hair-thin wire. Now you have all four wires from the coil ends.

    20191019_215036.jpg

    Look at the attached pic. The four insulated wires will attach to your coil ends. The bare wire connects to the pickup frame on one end, and ground on the other. The shield is the mylar wrap, that you can see tore apart when I tried to open it up to show you. You don't have to connect that to ground. It makes a ground connection because it touches the bare wire running through the cable, and that's grounded.



    On the guitar end, I assume you want OOP as an option, yes? Not the only sound. You could use a three-way on-on-on mini toggle to switch the humbucker between in-phase, OOP, and split coil. Connect that to the three-way pickup selector, and you have a normal Tele with three options for the neck pickup.


    Screen Shot 2019-10-19 at 10.35.40 PM.png
     
  5. mkdaws32

    mkdaws32 Tele-Meister Ad Free Member

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    Quick question for clarification. Do you want the two coils of the miniHb to be out of phase with each other, or out of phase with the bridge pickup? I would think the latter would be a more useful sound and it would not require major surgery on the miniHB.

    Or perhaps you meant you want to use the pp to switch the miniHB from series to parallel wiring, which would be IMHO a much more useful tone, and completely different, than out of phase. This would require converting the pickup to a four conductor as @moosie suggets.
     
  6. moosie

    moosie Doctor of Teleocity Ad Free Member

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    I was going to ask that right off, but for some reason the OP's post convinced me he was asking the thing I addressed. But based on his answer to my post, I'm no longer certain.
     
  7. acer

    acer TDPRI Member

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    Hey, really appreciate your help guys, I have much clearer picture now. Ok, so here's what I want - it's a tele with minihums, 3 ways toggle switch, and a push pull tone pot. After lots of homework I'm certain that I only want one more option - the neck pup oop with the bridge.

    So looking back at moosie's answer did you mean a pickup oop in itself with that method? If so, that's not what I want.

    My understanding right now is that if I seperate the bare wire and ground that, then isolate the braided wire so the outside ground is not touching anything can I then proceed just like how you'd do with a tele's neck pickup to go oop?

    Thanks a bunch guys :)
     
  8. moosie

    moosie Doctor of Teleocity Ad Free Member

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    Yes, that's what I was describing, so nevermind... :lol:

    Is your bridge a mini as well? Because if it's a typical single, or anything with two leads instead of the braided shield, you can just switch the bridge leads instead of the neck. In this circuit just one pickup switches leads, but it doesn't matter which pickup. That might be easier than dissecting the braided lead.

    But yes, to do what you're asking, you need to have three leads coming off the pickup. One is hot, two is common, three is the bare wire to ground, grounding the pickup body. If you don't mind no shielding when OOP, you could disconnect the braid from the coil, and leave it connected to the frame, as your bare wire. Then add a common lead, connected to the coil. If you prefer to have shielding both ways, use the shielded 4+1 wire I suggested earlier, just don't hook up the red and white.
     
  9. acer

    acer TDPRI Member

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    Yep, both minihums but I just realised maybe I go with the bridge pup anyway since it's closer to the control plate, the wiring could be tidier that way.

    I'm thinking the opposite though - use the braid for the common(insulate it from touching the case) since it's already connected to the coil then disconnect the bare wire from the braid and add an extra wire connecting the bare wire to ground like how you'd do it with tele's neck pup. This way it should work right? It should be shielded in all situation.
     
  10. moosie

    moosie Doctor of Teleocity Ad Free Member

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    That will work, though insulating the bare, and then add another bare, seems like extra work. And no, it won't be shielded when out of phase, because your 'hot' will be the braid.
     
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  11. acer

    acer TDPRI Member

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    Right, got it, thanks very much.
     
  12. mkdaws32

    mkdaws32 Tele-Meister Ad Free Member

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  13. Vizcaster

    Vizcaster Poster Extraordinaire

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    I think what the OP wants to do is to avoid any rewiring of the pickup and to try to use the braided shield inside out. Simply insulating the braid from shorting out against anything is not going to solve all the problems that creates. If the mini-hums have a metal cover then the cover is attached to the braid, for shielding, and your scheme would make the covers hot. Which means if you touch the pickup cover you'd get the same loud noise as if you touched the tip of a guitar cord. If you ran a separate ground wire to the cover then if it touches the braid (for instance if your shrink wrap pulls back or wears through where it passes through the base plate of the pickup) it will short out the pickup.
     
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