How To Measure Pickup DC Resistance

Discussion in 'Pickups' started by matt@msscguitar, Feb 12, 2014.

  1. matt@msscguitar

    matt@msscguitar www.MSSCGuitar.com Premium Member V.I.P. Member MLP Vendor

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    Here's a quick and easy pictorial of how to measure pickup DC resistance using your multi-meter.

    For illustration purposes, I'm using my test rig that I use to test wiring harnesses after they are built, so there are ALOT of wires that you don't need to concern yourself with for this exercise. The bridge pickup we'll test is 4 conductor, and I've marked all the appropriate leads in the picture.

    ** If you want to test single conductor braided pickups, all you need to do is put on lead of your meter on the inner hot wire, and the other lead on the outer braid which acts as the ground. Make sure that none of the outer braid comes in contact with the hot or you won't get a reading. **

    The testing rig:

    [​IMG]

    Note we have (4) leads - Hot, Series Links (combined into 1), Ground (Covered), and Bare Ground Wire.

    If you don't have an auto-sensing meter like this one, set the range to 20K.

    [​IMG]

    As depicted, I took the HOT from the pickup and connected to one lead on the meter. I then took the Bare AND Covered Ground wires and connected those to the other lead on the meter.

    Now if you wanted to test just the coil split (1/2 the pickup), substitute the hot lead from the pickup with the series link wires (Ex. Seymour Duncan uses Red+White as the series links, so you'd test those wires - Mine is already presoldered into one "series link" lead for simplicity purposes).

    [​IMG]

    Notice the output is roughly 1/2 of the full pickup output of 8.05K. Everything works fine!

    Lastly, if your wanting to test DC resistance of pickups that are already installed in your guitar, its as easy as plugging a guitar cable into the input jack of the guitar, and connecting a multi-meter to the other side of the cable as follows:

    [​IMG]

    You may get a *slightly* different value using the above testing method because of the caps and pots being connected to the circuit. It should not deviate by much.

    Here's another way too, assuming the pickup is already wired up:

    [​IMG]

    [​IMG]

    One leg of the meter gets clipped to the volume pot lug where the pickup is connect, the other leg clipped to the outer braid of the pickup. Make sure your volume is all the way up :)

    Hope this helps!
     
  2. jamman

    jamman Premium Member

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    Good stuff Matt . Should be a Sticky . Those who need this should have it available easily . :thumb:
     
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  3. matt@msscguitar

    matt@msscguitar www.MSSCGuitar.com Premium Member V.I.P. Member MLP Vendor

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    Thanks, Jeff! :)
     
  4. tazzboy

    tazzboy V.I.P. Member

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    OK how about on braided shield wiring?
     
  5. Alligatorbling

    Alligatorbling ★AstroCat★ Premium Member V.I.P. Member MLP Vendor

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    the braided shiled itself the ground, the wire coming out of the shielded cloth is the hot wire
     
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  6. captcoolaid

    captcoolaid Senior Member

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    what if my pickup reads 22k but my meter is only at 20k smart guy????? LOL
     
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  7. matt@msscguitar

    matt@msscguitar www.MSSCGuitar.com Premium Member V.I.P. Member MLP Vendor

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    This.
     
  8. matt@msscguitar

    matt@msscguitar www.MSSCGuitar.com Premium Member V.I.P. Member MLP Vendor

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    :laugh2: Idiot!!! :laugh2::laugh2:
     
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  9. AXE

    AXE Six String Soldier V.I.P. Member

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    Will a shorter output cable for the installed pickup method give a more accurate reading?

    I usually use a solid offset pedal jack just because...

    Visual aid.
     

    Attached Files:

  10. Alligatorbling

    Alligatorbling ★AstroCat★ Premium Member V.I.P. Member MLP Vendor

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    ^i think you should plug into your amp like that. better tone. less signal path so you get more tone to your amp.


    play live like that too axe.
     
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  11. AXE

    AXE Six String Soldier V.I.P. Member

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    okay.
     
  12. matt@msscguitar

    matt@msscguitar www.MSSCGuitar.com Premium Member V.I.P. Member MLP Vendor

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    Maybe, maybe not, Rick. If there is a deviation, I would think it could be slight. The pickup winding folks could probably shed more light on that.
     
  13. AXE

    AXE Six String Soldier V.I.P. Member

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    Thanks Matt.

    That's a badass V huh?

    [​IMG]
     
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  14. 7gtop

    7gtop Premium Member

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  15. matt@msscguitar

    matt@msscguitar www.MSSCGuitar.com Premium Member V.I.P. Member MLP Vendor

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    Here's another way too, assuming the pickup is already wired up:

    [​IMG]

    [​IMG]

    One leg of the meter gets clipped to the volume pot lug where the pickup is connect, the other leg clipped to the outer braid of the pickup. Make sure your volume is all the way up :)
     
  16. ghost driver

    ghost driver Senior Member

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    Thanks for this great post Matt. This is very helpful. Even to members who have done this its great to see how you would do it. I also think it would be a good sticky (I see it already is).
     
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  17. blues_n_cues

    blues_n_cues Senior Member

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    here's a question, I did mine using the cable end/multimeter method on a Les Paul w/ 57's in it & 50's wiring.-

    Bridge-13.25
    Neck-8.85
    but when in the middle position it reads 5.08

    I'm not sure if that's normal but when playing it sounds like full output.:hmm:
    I do know there is an open ground or cold solder joint somewhere @ the moment but I haven't found it yet.
     
  18. freefrog

    freefrog Senior Member

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    It's totally normal: two pickups in parallel measure the sum of their DCR's divided by 4. And you have 4 pots in the circuit instead of two, whose DCR drags down the whole DCR too.
     
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  19. Lefty Bob

    Lefty Bob Member

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    Don't forget about the temperature of the coil.
    When ever possible measure DC resistance at 68*F (20*C) .
    I use an IR temp gun to read the temp of the coil when I measure DC resistance
    For every 5 degrees under or over 68*F add or subtract 1%

    Ex: 7.57k ohms measured at 73*F = 7.494k ohms.
     

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