If you have 250k pots, can you replicate having 500k pots with a Parametric EQ?

Discussion in 'Guitars in General' started by james..., May 6, 2016.

  1. james...

    james... Member

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    Simple question....
     
  2. dconeill

    dconeill Member

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    No. EQs can't put in what isn't there, they can only act upon (and reduce aspects of) the original signal.
     
  3. james...

    james... Member

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    Isn't that what a 500k would be doing?

    Or do I have that backwards?
     
  4. kiki_90291

    kiki_90291 Member

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    500ks let more treble through
     
  5. james...

    james... Member

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    So vice versa, if I had 500k pots, could I simulate 250k with EQ?
     
  6. buddastrat

    buddastrat Member

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    I find different value pots change the way the taper works. I know it's supposed to be audio or linear that does that. But I never seem to like any 500K A or L pot's taper. The 250K tapers are always much nicer and gradual. So obviously an EQ is not going to help any of that.

    As far as adding/subtracting treble or a bit of output, I don't see why an EQ couldn't do that and way beyond.
     
  7. eigentone

    eigentone Supporting Member

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    Not in a practical way. Don't bother. Varying the resistance affects the frequency response of the pickup. Eg basses get a big mid hump when rolling the tone down. Rolling the tone back affects the whole circuit.

    Simplified: When the tone's open wide enough or out of the circuit, there will likely be a resonant peak around 2-5 kHz (ice pick territory). Then roll back and that peak is reduced. Roll back more and it acts like a LPF. Roll back more and it acts like a mid boost.

    The tone control is not isolated from the pickup. They are in the same circuit and the pickup reacts to the changes in the tone knob. If you were to first buffer the signal (Pickup -> Buffer -> Tone), then the a tone knob would behave differently because it would not influence the pickup.

    You can simulate it by matching the resistance with your 500k tone knob.
     
    Last edited: May 6, 2016
  8. cardinal

    cardinal Supporting Member

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    I would just switch to 500k pots plus the resistor trick to get to 250k resistance...

    Or I would just not worry about it... Single coils with 500k pots can be a bit ear splitting, but whatever with 250k pots seem to do ok in my experience.
     
  9. Pointy Headstock

    Pointy Headstock Member

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    Not really...I think you need to better explain the scenario that's driving your question. Do you have a guitar that's too dark/bright? Are you attempting to try to match sounds between guitars? Simply trying to figure out if it can be done?
     
  10. SPROING!

    SPROING! Member

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    A 250k pot has less ground to cover given the same rotation of the shaft vs a 500k. The 250k pot is more sensitive. 1 meg pots are so jumpy as to be nearly unusable.
     
  11. dconeill

    dconeill Member

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    There's a signal that comes out of the pickups with a certain frequency response. Passing that signal through a pot acts as a low-pass filter. If you use 250k pots in the guitar, the highs coming from the pickup are attenuated a certain amount. If you have 500k pots in the guitar, then the highs coming from the pickup are attenuated less than if you had used 250k pots.

    The signal that goes out from the pots, therefore, has already been low-pass filtered. Putting that signal into an eq won't restore the high frequencies that were rolled off by the presence of the pots. Consequently, if you have a guitar with 250k pots, you can't simulate having 500k pots with an eq because the high frequencies have already been attenuated in the guitar's electonics and never make it to the eq.
     
  12. Mark Kane

    Mark Kane Silver Supporting Member

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    You could ad a 270k resistor to the wiper of your 250k pot. It will effect the taper and you may or may not be happy with that. Added more highend at the amp or with an effect will also change the sound. In the end the real answer to stuff like this is personal experience. for a couple of bucks you can learn a lot of fun and useful things.
     
  13. buddastrat

    buddastrat Member

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    that makes sense, guess that's why I like 'em, I use the knob a lot for different subtle variations. They get such sweet violin swells.
     
    SPROING! likes this.
  14. sg~guy

    sg~guy Member

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    -no-

    -1 meg pot's are the only ones I use-
     

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