Pot resistance values - highest for volume or tone?

What's Hot
Very possibly insignificant I know, but just thought I'd ask the advice of the forum experts - say I've bought two "500K" pots, one I measure at 485K, the other at 535K, just to invent an example - which is it best to use the higher value one for, volume or tone? Cheers! :)
0reaction image LOL 0reaction image Wow! 0reaction image Wisdom · Share on Facebook Share on Twitter

Comments

  • AlegreeAlegree Frets: 219
    Doesn't really matter, they end up in parallel regardless so it probably has no effect whatsoever.
    Alegree pickups & guitar supplies - www.alegree.co.uk
    0reaction image LOL 0reaction image Wow! 1reaction image Wisdom · Share on Facebook Share on Twitter
  • MegiiMegii Frets: 808
    Alegree said:
    Doesn't really matter, they end up in parallel regardless so it probably has no effect whatsoever.
    Cheers @Alegree, great if that's the case - any other views on this one though? I doubt it does matter much, but if there is some theoretical reason to go one way or the other, I'd like to know all the same.
    0reaction image LOL 0reaction image Wow! 0reaction image Wisdom · Share on Facebook Share on Twitter
  • ICBMICBM Frets: 25744
    With that small a difference it doesn't matter - both are well within the tolerance range and it's very unlikely you would hear a difference.

    They are not really in parallel though, because the tone cap is in series with the tone pot. The volume pot is a potential divider and the tone pot is a simple variable resistance connected to the cap.

    You will hear a difference if you use properly different values, eg 250K and 500K. If so I always prefer to have the volume control lower and the tone higher - to me that gives a deeper but clearer sound. Volume higher than tone gives a more muted, jazzy tone… it's actually exactly the same as using two high-value pots and turning the tone down until it's the same resistance as a lower-value one.
    "Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone."
    0reaction image LOL 0reaction image Wow! 1reaction image Wisdom · Share on Facebook Share on Twitter
  • MegiiMegii Frets: 808
    FWIW my current wiring project is to make a loom for an Ibanez semi-acoustic guitar, to which I'll be fitting a couple of Oil City humbuckers - a 7.6K Blitz Spirit in the neck and a 14.5K Nightfighter in the bridge. I have got 4 Bourns mini pots, and measure the values as 526K, 530K, 554K and 567K.

    Unless anyone's going to tell me something different, I'm going to go:

    Neck volume 526K
    Neck tone 530K
    Bridge volume 554K
    Bridge tone 567K

    - higher values on the bridge, because it's a higher output pickup, and the slightly higher values for the tones compared to volumes because it has a 50-50 chance of being right (I have no idea), and the values are so close it almost certainly won't matter... :D 
    0reaction image LOL 0reaction image Wow! 0reaction image Wisdom · Share on Facebook Share on Twitter
  • MegiiMegii Frets: 808
    ICBM said:
    With that small a difference it doesn't matter - both are well within the tolerance range and it's very unlikely you would hear a difference.

    They are not really in parallel though, because the tone cap is in series with the tone pot. The volume pot is a potential divider and the tone pot is a simple variable resistance connected to the cap.

    You will hear a difference if you use properly different values, eg 250K and 500K. If so I always prefer to have the volume control lower and the tone higher - to me that gives a deeper but clearer sound. Volume higher than tone gives a more muted, jazzy tone… it's actually exactly the same as using two high-value pots and turning the tone down until it's the same resistance as a lower-value one.
    Thanks @ICBM - I think I would prefer the deeper but clearer option myself. I just posted the actual values for the project I'm doing before seeing your post, so would be grateful if you could just cast your eyes over my proposed arrangement of pot values and see what you think? Cheers! :)
    0reaction image LOL 0reaction image Wow! 0reaction image Wisdom · Share on Facebook Share on Twitter
  • ICBMICBM Frets: 25744
    I've you've bothered to measure them you might as well :). For the same reason, I always measure a set of "identical" pickups and put the highest one at the bridge and the lowest at the neck, if there's no other consideration - it may not make *much* difference, but it certainly won't make the *wrong* difference either!

    All those values are within 8% of each other whichever is the 'base' value though, and when I did some direct A/B testing, the smallest difference I could reliably hear was about 25% (down) and 33% (up) from the marked value. That doesn't prove there isn't a detectable difference closer than that, but if there is it's unlikely to make any real difference in use.
    "Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone."
    0reaction image LOL 0reaction image Wow! 1reaction image Wisdom · Share on Facebook Share on Twitter
  • MegiiMegii Frets: 808
    ICBM said:
    I've you've bothered to measure them you might as well :). For the same reason, I always measure a set of "identical" pickups and put the highest one at the bridge and the lowest at the neck, if there's no other consideration - it may not make *much* difference, but it certainly won't make the *wrong* difference either!

    All those values are within 8% of each other whichever is the 'base' value though, and when I did some direct A/B testing, the smallest difference I could reliably hear was about 25% (down) and 33% (up) from the marked value. That doesn't prove there isn't a detectable difference closer than that, but if there is it's unlikely to make any real difference in use.
    Cheers again - I did doubt there'd be any perceptable difference, whatever I did, but I guess a bit of an OCD nature still makes me want to know what's best in theory. Appreciate your help - I'll stick to my plan then, in light of what you say. :)
    0reaction image LOL 0reaction image Wow! 0reaction image Wisdom · Share on Facebook Share on Twitter
  • AlegreeAlegree Frets: 219
    ICBM said:
    With that small a difference it doesn't matter - both are well within the tolerance range and it's very unlikely you would hear a difference.

    They are not really in parallel though, because the tone cap is in series with the tone pot. The volume pot is a potential divider and the tone pot is a simple variable resistance connected to the cap.

    You will hear a difference if you use properly different values, eg 250K and 500K. If so I always prefer to have the volume control lower and the tone higher - to me that gives a deeper but clearer sound. Volume higher than tone gives a more muted, jazzy tone… it's actually exactly the same as using two high-value pots and turning the tone down until it's the same resistance as a lower-value one.
    A cap and a lower pot value achieve more or less the same thing, rolling off treble.
    I can't see why you can't look at it as being in parallel at all in practice, if not looking from a theoretical perspective.
    Alegree pickups & guitar supplies - www.alegree.co.uk
    0reaction image LOL 0reaction image Wow! 0reaction image Wisdom · Share on Facebook Share on Twitter
  • ICBMICBM Frets: 25744
    Alegree said:

    A cap and a lower pot value achieve more or less the same thing, rolling off treble.
    I can't see why you can't look at it as being in parallel at all in practice, if not looking from a theoretical perspective.
    No they don't.

    The tone control works by shunting treble frequencies to ground. The volume control alters the treble response by interacting with the inductance of the pickup. Quite different mechanisms, and the sound change is very different.

    The two value changes actually work independently because of this, which is why Megii's question is important. A 250K volume and a 500K tone does not sound at all the same as a 500K volume and a 250K tone, which it would if they were in parallel.
    "Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone."
    0reaction image LOL 0reaction image Wow! 2reaction image Wisdom · Share on Facebook Share on Twitter
  • AlegreeAlegree Frets: 219
    ICBM said:
    Alegree said:

    A cap and a lower pot value achieve more or less the same thing, rolling off treble.
    I can't see why you can't look at it as being in parallel at all in practice, if not looking from a theoretical perspective.
    No they don't.

    The tone control works by shunting treble frequencies to ground. The volume control alters the treble response by interacting with the inductance of the pickup. Quite different mechanisms, and the sound change is very different.

    The two value changes actually work independently because of this, which is why Megii's question is important. A 250K volume and a 500K tone does not sound at all the same as a 500K volume and a 250K tone, which it would if they were in parallel.
    I disagree that the tonal difference is significantly different, especially given the small values here. But hey, that's just my unscientific opinion. 
    Alegree pickups & guitar supplies - www.alegree.co.uk
    0reaction image LOL 0reaction image Wow! 0reaction image Wisdom · Share on Facebook Share on Twitter
  • RiftAmpsRiftAmps Frets: 685
    edited September 21
    Alegree said:
    ICBM said:
    Alegree said:

    A cap and a lower pot value achieve more or less the same thing, rolling off treble.
    I can't see why you can't look at it as being in parallel at all in practice, if not looking from a theoretical perspective.
    No they don't.

    The tone control works by shunting treble frequencies to ground. The volume control alters the treble response by interacting with the inductance of the pickup. Quite different mechanisms, and the sound change is very different.

    The two value changes actually work independently because of this, which is why Megii's question is important. A 250K volume and a 500K tone does not sound at all the same as a 500K volume and a 250K tone, which it would if they were in parallel.
    I disagree that the tonal difference is significantly different, especially given the small values here. But hey, that's just my unscientific opinion. 
    I agree with @ICBM here, there is a difference.

    If you want proof, connect both an oscilloscope and spectrum analyzer to the output of an amplifier, plug in the guitar and use an EBow or similar to stimulate a string at a more-or-less constant. Watch on the spectrum analyzer as you first turn down the Volume control, then up again. Do the same with the Tone control. You will see a marked difference in the effect each control has. Once you understand what's actually going on, your ears will learn the differences too.

    Rift Amplification
    Handwired Guitar and Bass Amplifiers
    Brackley, Northamptonshire
    www.riftamps.co.uk
    0reaction image LOL 0reaction image Wow! 1reaction image Wisdom · Share on Facebook Share on Twitter
Sign In or Register to comment.