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250k vs 500k pots can you really HEAR the difference?

Discussion in 'Pickups & Electronics [BG]' started by keyboardguy, Jan 4, 2007.

  1. keyboardguy

    keyboardguy Supporting Member

    May 11, 2005
    Hi all,

    I have searched and read virtually every post here at TB, and am familiar with the advice to use 250K pots for single coil pups (to sound darker) and use 500k pups for humbuckers (brighter)

    Now my questions.
    If you use 500k on your single coil pickups, how are they 'brighter'? Just when you have the tone control all the way up?
    What about when the tone is turned off? Would your still hear a difference between the 250 and 500k?

    And are we just talking about the tone pot? will 500k volume pots sound brighter than a 250, all other things being equal??

    The reason I'm asking is that I've been using 500k audio tapers for all my rebuilds and want to make sure I can get the best low end thump.
    Using the same .047 capacitors, will the 500k volume/tone pots REMOVE ANY low end? or just ADD treble when the tone pot is turned all the way up?

    Hope my questions haven't confused you all.... <G>


  2. Gyoon


    Nov 12, 2004
    Toronto, Ontario
    The 500k pots will retain your high end while maintaining all the bass that you would get from, say the 250k pot.

    Here's a layperson's, semi-informed-but-not-really explaination of what's shakin':

    Your pickup wire gets connected to the 3rd lead and comes out of the middle lug. The 1st lug gets connected to ground. When your pot is rolled up all the way forward what you essentially have is a 500k resistor hooked up parallel to your signal "shunting" it to ground. What this does is take some of your signal to ground (out of the audio path where it makes it to your amp). A 250k pot will do the same thing but provide only 250k ohms of resistance to ground. This means that more of your signal gets lost to ground.

    Your high end gets eaten away at first. Theres a better explaination out there as to why, I just can't think of it. Treble is weak; bass is indestructable.

  3. *smb


    Nov 26, 2006
    Treble is attenuated more by the resistance more.

    If you think about it, a bass signal has a much lower frequency and so acts much like a DC current. DC can go through a resistor fine, but can't get across a capacitor. Treble acts as an AC current for which a resistor is more of an obstical than a capacitor is.

    I hope this makes some sense. If you apply these principles to the circuit you find in your bass you can see how the tone control changes the signal and what effect changing the pots could have.
  4. edwinhurwitz

    edwinhurwitz Supporting Member

    May 13, 2003
    Boulder, CO
    Endorsing Artist: DR Strings, SMS
    In a word, yes. However, what the proper value is depends on the circuit. It would seem like if 500k passes more highs than 250k, 25k would pass no highs at all, but in a low impedance situation, it works perfectly and gives you finer control over the part of the taper that matters.

  5. keyboardguy

    keyboardguy Supporting Member

    May 11, 2005
    Thanks folks.

    I think I got it: if the tone is turned off all the way, the low end will be exactly the same and NOT change, no matter if you use a 250 or 500k tone (and volume) pots. Right?

    Who cares about treble? We're BASS PLAYERS <G>

  6. yeah who cares about treble?............well if you want a mudbox of a bass then thats fine :ninja:

    i found that with 250K i had really low signal with stacked buckers, but when i made the switch to 500K the volume and tone seemed to open up.
  7. Gyoon


    Nov 12, 2004
    Toronto, Ontario
    Actually, 500k passes LESS highs to ground than 250k. The reason that 25k pots are used in active basses is because they are used within the preamp circuit and have a different role. a 25k pot within a passive bass would send too much of your signal to gorund, giving you very little remaining signal.

  8. RyreInc


    May 11, 2006
    Kalamazoo, MI
    I beleive he meant pass as in it passes to the output (i.e. low and high pass filters)
  9. dls59

    dls59 Supporting Member

    I'm awaiting delivery of a used SX SPB57. I'm considering some mods, including pots. So, if I understand correctly, if I want the typical Fender Precision vibe, but with a bit more potential bite, I should use 500k pots instead of 250's?
  10. Whatever John Wetton used in his P-Bass should do just fine!
  11. dls59

    dls59 Supporting Member

    No joke!!!!
  12. To get the full sound out of an old bass I have, I removed the volume and tone pots and ran the pickup straight to the output jack. I control volume and tone from my floor effects setup. I don't know about you, but I never used my tone control on my passive bass. Like most I used the volume, but with a volume pedal in the floor unit I don't need it. I like the sound of the unrestricted output of the pickup.

    - Mark
  13. *smb


    Nov 26, 2006
    Yeah the old Queens bassist Nick Oliveri has several P-basses customised so the P pickup is wired straight to the output jack and he uses only a volume pedal. I'd do that with my Artcore bass if I didn't have to work on it through the f-holes!

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