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How important are the pots?

Discussion in 'Pickups & Electronics [BG]' started by honkyfunk, Dec 4, 2013.

  1. honkyfunk


    Dec 4, 2013
    Focusing on Fender P and J-Basses: How important are the potentiometers in terms of staying with "stock" or factory Fender pots or upgrading to more expensive? Does it make a difference in the quest for tone, or are the more expensive ones just "smoother" dialing or something? Building a P-bass or two. Any input greatly appreciated.
  2. Makes no difference in tone, unless you're changing values.

    Aside from tolerance, the only things to worry about in this application are the quality of the taper, and the mechanical aspects of the pot, such as the rotational inertia required to adjust it.
    Higher quality pots will be more sturdy and have a tighter tolerance and smoother taper.
  3. Hopkins

    Hopkins Supporting Member Commercial User

    Nov 17, 2010
    Houston Tx
    Owner/Builder @Hopkins Guitars
    What he said.

    Pots of the same value with sound no different, but cheaper pots can vary quite a bit in the actual value of the pot. I have seen cheap 500k pots measure at 425k all the way up to 550k. Better pots usually are much closer than their advertised value.
  4. honkyfunk


    Dec 4, 2013
    This is great, guys. Thank you! Makes sense. I did notice one of my cheaper volume pots has all of its influence piled up at the very end of the last quarter turn. Yikes.
  5. Those are acceptable values for a 20% tolerance, which is common.
  6. Hopkins

    Hopkins Supporting Member Commercial User

    Nov 17, 2010
    Houston Tx
    Owner/Builder @Hopkins Guitars
    Still, I find that cheaper pots are more prone to be on the outer edge of that tolerance. 20% in either direction can make a pretty noticeable difference in the sound produced.
  7. Electricblue


    Feb 1, 2011
    I wouldn't worry about the tolerance unless you're very particular about your sound. I changed my Squier Jazz pots from cheap 250k's to 500k CTS pots, and I only just noticed the difference. So I doubt a 20% tolerance would make a drastic difference.

    To the OP, the reason your cheap pot has all the range in a certain area is that it's probably a Linear taper, not an Audio taper pot.

    The only real difference between expensive and cheap will be the reliability/feel. There's no magic in expensive pots. 500k is 500k (apart from tolerance)
  8. kohntarkosz

    kohntarkosz Banned

    Oct 29, 2013
    Edinburgh - Scotland
    That isn't anything to do with the cost of the pots. It sounds like they used the wrong taper for the pots, which could happen at any price range.

    For what it is worth I've purchased some horrible CTS pots before today. I've also had astonishingly good luck with cheaper 'mini' pots. Make of that what you will. Pots and caps are typically not the vast tonal 'bottleneck' that some modders would love to believe, and any upgrades will be subtle if detectable at all. Going from 250k pots to 500k (or 1meg if you want to watch the world burn) will be the most noticeable change you can make, but again this isn't down the construction quality of the pots themselves.
  9. honkyfunk


    Dec 4, 2013
    Thank you ! Good info.
  10. Electricblue


    Feb 1, 2011
    The pots don't mean a thing, as long as you use a jimungous tone capacitor that's rated for a higher voltage than your bass will ever see ;)
  11. It's the other way around. Audio taper pots are commonly manufactured from two linear resistive segments joined to approximate a log curve. This tends to cause a big jump in volume in the last fifth or so of the rotation. Linear taper pots spread out the resistance evenly.
  12. chienmort


    Aug 15, 2012
    Unfortunately our hearing is logarithmic in how it respond to sound. A linear pot is all wrong for Volume but may work as Tone or EQ depending on how the circuit is designed. Audio taper pots are pseudo logarithmic and there can be a small jump but it is not serious. The best law or taper is where a linear pot has it's resistance modified by a normal resistor. Look on the net for The Secret Life of Pots or www.sound.au.com and read the articles on pots for more info.
  13. Our hearing is, but you are not talking about the amplitude of longitudinal pressure waves here. This is a preamp gain stage, not a power amp. And furthermore, you're not trying to achieve linear-sounding fades. You are only trying to blend pickup signals. Even if a log taper were desirable, you wouldn't get a true log taper here, because of the resistive loads on each pot that alter its taper.

    In any case, this is a topic of considerable debate, and you will find diehard fans of both tapers. Do some searches here for cases from both sides.

    As a side note, linear tapers are not suitable for tone controls. The ideal tone control has an infinite resistance at the full setting, to "bypass" the LPF. However, the resistance needs to be considerably lower throughout the usable range of control, for any given signal impedance. This means that linear taper pots tend to behave more like on/off switches, where large portions of the rotation have little effect on tone, and all of the action happens at one end of the rotation. Audio taper pots are best for tone controls, because they drop off very fast, as soon as you roll down from "10," and this takes you into a usable range of resistance that is spread out over a wider portion of the rotation.
  14. BluesOnBass

    BluesOnBass Supporting Member

    Dec 17, 2010
    Holland, Michigan
    So.... audio taper for tone pots, and linear for volume?
  15. Audio taper pots are traditional of both volume and tone controls, but there is enough debate on volume pot tapers that it is best to just try both tapers and pick a favorite.
  16. walterw

    walterw Supportive Fender Gold Supporting Member Commercial User

    Feb 20, 2009
    ...and after installing probably hundreds of them over the last few years, i'm firmly in this camp for bass!