DC Resistance or Millivolt (mV)

Discussion in 'Pickups' started by scozz, Oct 4, 2017.

  1. scozz

    scozz Senior Member

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    I've noticed a lot of folks measure a pickups DC Resistance and equate that with the output of the pickup. From what I've read DC Resistance is only one of many things to consider when determining the output of a pickup. And that using the millivolt reading, (mV) is a much more accurate way of measuring the output.

    For example...a Dimarzio Super Distortion, (listed as a HIGH output PU) has a DC Resistance of 13.68k and a mV of 425...

    ...while a Dimarzio AT-1, (listed as a MEDIUM output PU) has a DC Resistance of 16.50k and a mV of 320.

    What's the consensus here?
     
  2. DarrellV

    DarrellV Almost 1 Year old this month! Premium Member

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    Hey scozzy! :cheers:

    The winders in here will all tell you that DCR is a waste of time at best, and only used by MFRS because consumers demanded something they could use for buzz words.

    DCR changes with the length of wire, true, more wire, more resistance.... but also with gauge, or wire thickness.

    Thicker wire used for an equal length will still give lower resistance.

    Less of thinner wire and more of thicker wire also equal in resistance. So it's futile.

    Add to that you amp does not see resistance. Resistance impedes current, it doesn't actuate anything of itself. So it cannot drive the front end of your amp.

    mVolts, now THAT is a motive force that can and does drive the front end of your amp.

    Voltage, or Electromotive Force is the invisible stuff that pushes electrons down the wire.

    More voltage, more push, more current flow. it's the same at the mV level as it is in the kV level.

    So in a pickup, more mV = more push, what we call 'hotter' hitting the preamp with more force. Less amp gain is needed to reach breakup.

    Less mV = lower output usually cleaner and takes more to get it to break up.

    Makes sense because the pickup is hitting the front end with less juice, so we crank the pre amp knob for more boost.
     
  3. Antigua

    Antigua Senior Member

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    The DC R just suggests how many winds of wire are on the coil(s), but you have to know, or be able to guess the gauge of the wire in order to make much sense of it. The only truly useful value is the inductance, because the actual output voltage is dependent upon the impedance of the coil(s). The other factor, which is harder to quantify, is how much flux change can be seen by the pickup as the strings move around, as pickups operate based on Faraday's Law. This is why ceramic produces more output, because the ceramic magnetically charges the strings more strongly when the strings come closer to the pickup, so there is greater flux change, hence a higher voltage output. So there is potential that change when you swap out the magnets, and other parts, that is hard, or maybe impossible, to express as a single number. You'd need something like an internationally agreed upon standard, then you can say, under conditions X, the pickups produces output Y, and then that value could be meaningfully exchanged.

    The thing about DiMarzio's mV output is that we have no idea what methods they use to gather that data, and we have no ability to be certain that they use precisely the same method for every pickups tested. If they were just making these numbers up, we'd have no way to prove or disprove it. They have no incentive to be precise or consistent, considering they can't be held to account. If ever you disagreed with their values, they could just claim you didn't set the pickups to the correct height, or used guitar strings that were too thick or too thin, etc.
     
    Last edited: Oct 4, 2017
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  4. ARandall

    ARandall Senior Member

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    And then if you were to get a certain consensus on output, that might change with the amp and speaker used.....as amps are not linear or flat in their boost, and neither are speakers.
     
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  5. scozz

    scozz Senior Member

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    Thanks Darrell! :thumb: Great info!

    BTW...did you see this thread...

    Hey Darrell...Check this Out!
     
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  6. darthphineas

    darthphineas Senior Member

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    mV. always Mv.

    except that there's no 'industry standard', so that if all companies used the mV system, it wouldn't translate from one company to another. however, it should be a good scale among the products of a specific company that does offer output rating in mV.

    going with DCR is a fallacy that's gone on way too long and it should be an embarrassment that one of the big companies fed in to that for as long as they did (and sorta still do).

    for a quick example of how DCR does NOT equal output go to the DiMarzio site and look up the DCR and mV specs on the Super D, the Super 2 and the Super 3.
     
  7. scozz

    scozz Senior Member

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    Right.

    That's what I was referring to....

    ...a Super 2 has a DCR of 8.7k and a mV of 400 (high output)...

    ...a Super 3 has a DCR of 25.00k and a mV of 435 (high output)

    ...a PAF 59 has a DCR of 8.5k and a mV of 215 (vintage output)...
     
  8. darthphineas

    darthphineas Senior Member

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    :thumb:


    ...a Super 2 has a DCR of 8.7k and a mV of 400 (high output)...
    ...a Super 3 has a DCR of 25.00k and a mV of 435 (high output)

    a Super D has DCR of 13.68 and a mV of 425

    all output in the similar mV range with DCR ranging from 8.7 (what some would call vintage) to 13.68 (what some would consider medium-hot) to 25.00 (what everyone would consider scorching).

    some players don't care for DiMarzio for all sorts of reasons, but they deserve a bit of credit for doing their part to dispel the "DCR = output" myth



    still, it's all moot if there's not a common method that all pickup companies use to measure mV. it'd be cool if it happened, but there's little realism in the hope that it might. ;)
     

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