Know lots about potentiometers

Discussion in 'Pickups, Electronics & General Tech' started by noodles, Feb 16, 2007.

  1. DaPsyCho

    DaPsyCho SS.org Regular

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    Yes you will. Active pickups are electromagnets and hence require different amount of resistance to give out a "guitar" sound.

    Basically, the lower rated the pots (the lower K it has), the more warmer/duller tone u get. Passive pickups aren't very trebly, at least not as much as actives, hence they have higher rated pots, to give them more "punch" or treble and make them sound like a guitar should (the balance between bass, mids, and treble).

    But Active Pickups have much more treble, and not as much bass, which is why they almost never sound "muddy" and sound "crisp". But the thing is this extra treble needs to be balanced out, to give out a sound that is pleasing and more guitar-like. Hence to cut the treble, Actives use low rated pots usually 20-25K. U can see the difference between the normal 500 for a passive and a 25 for an active, and thus using a 500K pot on actives will sound quite terrible and m8 make ur ears bleed due to the insane amount of treble.
     
  2. guitarneeraj

    guitarneeraj WindMarp Contributor

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    First off, no pickup is an "electromagnet". Electromagnets are the opposite of guitar pickups, look up the E-Bow.

    I won't get into the details of how and why, the bottom line IS this -> Active pickups = Passive pickups + integrated preamp (cast together in epoxy). The distinct character of active pickups depends on how the preamp is designed (almost always an op-amp in differential configuration) and then the opamp chip itself and preamp circuitry contribute to the tone.

    With active pickups, it's possible to use ANY (yes, ANY) value for the volume and tone, however the lower limit depends only on the output impedance of the preamp circuit. An opamp's output impedance is very low, but for instance, EMG designs their preamp such a way that the output impedance is about 10k ohm. Which is why they recommend using 25k pots (Read about loading of a voltage source so you understand why you cannot theoretically go below 25k, although it IS possible). You can very well use values above this recommended value, but not BELOW. 25k is recommended by EMG as the thermal noise will be the least in a 25k pot.
     
  3. Omer45615

    Omer45615 SS.org Regular

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    Thanks for sharing.
     
  4. TRENCHLORD

    TRENCHLORD Banned

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    Bumping for advice.

    Getting ready to install an old x2n (been in box for 15yrs lol) and a brand new d'activator-x neck into my Guerilla w/basswood wings.
    I love the emgs in mahogany bodied guitars but am just wanting a different feel with this one, and that x2n is calling out to be used, I can really hear it :lol:.

    My questions are;

    Since I'd like to go toneless and be one volume only w/3-way switch, would I be better using a 1meg volume or 500k?

    Is there any distinguishable noise increase going up to 1meg with an x2n or any super high output pickup?

    Would there be any advantage to using two volumes, and if so what rating for them?

    My goal is to get as much attack and jolt possible from the bridge, and honestly the neck's performance is secondary to that.
    It's a thrash/DM guitar only so the neck will be for leads only (blended and separate).
    I'm not that concerned with being too bright because my amp has treble and presence knobs :lol:.
    If a 1meg or pair of them won't really help with the jolt/thud and they increase thermal noise then maybe it's not worth it. /?

    For any advice THANKS :metal:
     
  5. TRENCHLORD

    TRENCHLORD Banned

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    ^^^^^

    emailed dimarzio asking this, and they said;

    In a one volume only guitar there would be no appreciable difference between using a 1meg or a standard 500k if you are using a high gain amp.

    Anyone tried this and disagree?
     
  6. guitarneeraj

    guitarneeraj WindMarp Contributor

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    That is correct. :)
     
  7. Omer45615

    Omer45615 SS.org Regular

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