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Dummy coil problems

Discussion in 'Tele-Technical' started by Voicing 13, Apr 6, 2014.

  1. Voicing 13

    Voicing 13 Tele-Meister

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    Hi,

    I've been trying to install a dummy coil in a strat and things have been not going according to plan.

    The first possible issue that I have is that it's closed switch and I may not have the coil connected to the right place. It's one of those switch that have all the polls in a single row. The coil and the connection to the switch are supposed to be connected to the "A" polls. If I have figured this right they're the two middle ones.

    3
    2
    1
    A
    A
    3
    2
    1

    Could someone confirm or correct this?

    The switch is originally connected as below.

    3 (neck PU)
    2 (Middle PU)
    1 (Bridge PU)
    A (wire to the volume pot)
    A
    3
    2 (Black wire?)
    1

    What I have added.


    3 (neck PU)
    2 (Middle PU)
    1 (Bridge PU)
    A (wire to the volume pot+ dummy coil)
    A (Wire going to DPDT switch tone pot)
    3
    2 (Black wire?)
    1

    The dummy coil seems to always be engaged regardless of if the switch is on or off. I determine this because if I touch the dummy coil with a screw driver I get an active sound from it. Also the middle pickup seems to be weaker. Is this correct? I would image that if the dummy coil is off, that I should get no sound if I tap it. I've done alot of testing with alligator clips and therefore I know the issue is not with my soldering.

    I'd be grateful for any imput.
     
    Last edited: Apr 6, 2014
  2. waparker4

    waparker4 Doctor of Teleocity Ad Free Member

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    The dummy coil should be connected to the ground/neutral wire of the pickups not the switch in a stock strat

    In series: ground - dummy - pickup - output.

    Also keep in mind the middle pup may be rwrp in which case the wind direction that cancels noise for neck and bridge will worsen the noise for the middle - two dummy coils may be needed
     
  3. mabley123

    mabley123 Friend of Leo's

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    I would just get an Illitch noise reduction system and forget about it. Although they are expensive. they work. I got 1 for my partscaster and very build I do from now on will have 1.

    Mid pup needs to be non reverse wound.

    It also kills 0 highs
     
  4. Voicing 13

    Voicing 13 Tele-Meister

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    clarification

    My apologies, I forgot to mention that one of the tone pot is a push/push switch has well to allow to add or take off the dummy coil. I am also following the direction from Frettech:

    http://frettech.com/dummy/

    Therefore when I am talking about the "switch being on or off" I am refering the DPDT switch in the pot and not the pickup selector. Hope this clarifies.

    Thanks!
     
  5. Hiker

    Hiker Poster Extraordinaire

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    Ed Friedland has offered quite a bit of concepts about dummy coils, and what they are/do.
     
  6. Manolete

    Manolete Friend of Leo's

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    The bass whisperer?

    Rob DiStefano is the dummy coil dude on here, as far as I can tell.

    I've experimented with dummy coils before today, including one guitar that I then sold on to a mate. I wish I can remember what I did with that guitar, other than that the dummy was in the middle position, the guitar was wired as a Tele, and that it had its own control knob to blend it in.

    I think the tricky bit with sticking a dummy coil in a Strat is keeping it so that you can get the quacky tones in position 2 and 4 whilst keeping it so that the dummy coil cancels hum on all pickups. Usually if you set it up to cancel hum on the neck and bridge position it will double the hum on the middle pickup thanks to the winding of the pickups. Positions 2 and 4 would become a problem as you are combining the two pickups in parallel plus the dummy coil in parallel.

    I hope OP finds a good solution.
     
  7. Rob DiStefano

    Rob DiStefano Doctor of Teleocity Vendor Member

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    use a crl 5-way. the spst in the diagram and image below can be replaced with a tone pot push-pull. a bourn p-p pot can also be made into a no-load.

    [​IMG]

    [​IMG]

    here's a strat dummy with a bourns p-p dummy on/off pot switch ...

    [​IMG]
     
  8. Manolete

    Manolete Friend of Leo's

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    Would it be possible to make a phase flip switch for the dummy coil, so that it works with the middle pickup?
     
  9. waparker4

    waparker4 Doctor of Teleocity Ad Free Member

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    Yeah, I think with a DPDT on/off/on (or am I thinking on/on/on) switch it would be possible.

    It should also be possible to just have the strat switch do the work if you don't want switchable between hum / no hum. I'm thinking about that one currently
     
  10. Rob DiStefano

    Rob DiStefano Doctor of Teleocity Vendor Member

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    absolutely. did that with my last tele build, an on-on-on switch on the control plate so that one dummy would work with either pickup, and off in the middle so that the 2 pups would be in a parallel humbucking "normal" mode ...

    [​IMG]
     
  11. Voicing 13

    Voicing 13 Tele-Meister

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    Thanks everyone and I'm grateful for all your imput but unfortunately I'm still in the dark.

    I've followed the directions by Rob Distefano to the letter as his explantionations are always very clear. I'm using a push/push pot instead of the SPST mini switch. Here are the issues that I have:

    1. Because it's a closed switch (it's in a squier mini strat) for the pickup selector, I am not sure I am soldering wires to the right place.

    2. The dummy coil never seems to be off even when I turn the push/push pot switch off. If I touch it with a screw driver I still here a loud sound.

    3. I had everything working (now I am starting to doubt it) with alligator clips and soldering all the wires where the clips where and and then it stopped working. I've tried many combinations with no working results. I was worried that maybe I fried the push/push pot when soldering but I had another broken one and ran a test on it. There isn't anything that I could have fried beside plastic. I've also test the push/push pot switch with an omh meter and it tests out ok.

    So I am stumped. I'll go pick up a mini SPST switch soon to see if it is the part but if it's not I am really not sure what else it could be? If anyone has more insight or ideas of what I could test, please let me know. Thanks again to all.
     
    Last edited: Apr 7, 2014
  12. Rob DiStefano

    Rob DiStefano Doctor of Teleocity Vendor Member

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    i should preface this by asking - did you remove the magnet(s) from the dummy coil, and are you getting a good dcr reading on all the pups and the dummy coil?

    since it worked before soldering, is the circuit now soldered correctly? is there a cold solder joint or a short anywhere? is the dummy coil properly oriented to be the reverse wind of both the bridge and neck pups?
     
  13. Voicing 13

    Voicing 13 Tele-Meister

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    Rob, Yes, I removed the magnet, it's the first thing I did. Unfortunately I don't know what a drc reading is but when the push/push swtich is connected to the circut the the neck and the bridge are fine but the middle is weaker.

    When it didn't work I re-tested with alligator clips to be able to check different combinations and make sure it was my soldering. I couldn't get to work again? I'll check that again.

    As for the coils orientation it's hard to tell because there is little to no interference in my house that I've been able to find.

    Could you please confirm from my previous post if I am connecting to the right part of the pickup selector switch and is it normal to think that if the coil is not active I should not hear anything If I touch it with a screw driver? I'm still new to these kinds of mods and I don't fully understand how each part really work (Ie what each lug of a pot does or a pickup selector switch) and interact. Thanks for taking the time.
     
  14. Rob DiStefano

    Rob DiStefano Doctor of Teleocity Vendor Member

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    i only use crl or oak knife pup switches, can't help ya with that switch type, sorry. that surely could be the problem if it's not wired correctly.

    unless you've wound both the magnetic pickups and the dummy coil, you'll never be sure of their wind direction. if the dummy coil is inadvertently wired backwards, the level of humbuzz uncreases significantly, and hugely less when wired correctly.
     
  15. Voicing 13

    Voicing 13 Tele-Meister

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    I'll star from scratch tomorrow and unsolder everything that is not working and re-start. It's the only thing I have not done. The project is for a student of mine and his room is full of interference I'll check the coil at work where there is plenty of neon lights.

    Thanks again for your help Rob. I'll post again when if works.
     
  16. Voicing 13

    Voicing 13 Tele-Meister

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    Made moderate progress

    Ok, I finally realised I was wrong in thinking it had work. What is happening is that when the switch for the dummy coil is off the dummy coil is off and all the other pickups are off even when selected. If it's on, the dummy coil works and all the other pickups work when selected. So obviously the wiring is wrong and I need to understand how this import switch works.

    So at least I know it's not the push/push pot switch...Hopefully I will be further ahead this weekend.

    Thanks again for the help.
     
  17. Rob DiStefano

    Rob DiStefano Doctor of Teleocity Vendor Member

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    refer to the schematic i posted up top. the lead from the pickup select switch goes directly to one side of the dummy. the other side of the dummy goes to the input wiper of the vol pot. the dummy on/off switch goes from the pup select switch to the input wiper of the vol pot. when the dummy on/off switch makes contact, the dummy coil is bypassed and is out of the circuit.
     
  18. Voicing 13

    Voicing 13 Tele-Meister

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    Yup that's what I've got and I've been over that schematics a lot over the last few days:D Btw thanks again for posting it on your site. Second mod I do from one of your posts.

    After posting on the switch it's self I got a little more info. I've confirmed that I have wire going to the correct contacts of the pickup selector switch. This is a strat mini and for some reason the common contacts are not joined and there is a wire going to ground that seems to be doing nothing. I'll re-wire it the way a strat is normaly done and see if that does not solve it. If not, I'll see if I don't have a CRL switch laying around but it would probably be too long.

    Thanks!
     
  19. Voicing 13

    Voicing 13 Tele-Meister

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    Moving forward!

    Ok, disconnected the black wire, connected the commons this morning and I can now turn the dummy coil on and off. Of course my soldering iron died on me this morning and I am off to by another.
     
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