Audio or Linear taper tone pots??

Discussion in 'Technical Side of Things' started by Randy99CL, Jul 13, 2020.

  1. Randy99CL

    Randy99CL Synchromatic

    623
    Feb 17, 2020
    Albuquerque
    For those that have experimented with these...

    AFAIK tone pots should be linear taper. Audio taper is logarithmic with fast, coarse adjustment at one end and slow, very fine at the other. Linear taper pots should roll off the highs in an even, more controllable way.

    I'm wondering because a number of vendors recommend their CTS audio taper pots for both volume and tone. I haven't seen any CTS linear taper pots and guess they don't make them, are those vendors recommending the audio taper just because that's all they have???

    Everyone recommends CTS pots as the best and I like them OK but can get linear taper in other brands and wonder if I should mix/match.

    What do ye experts think???
     
  2. Uncle Daddy

    Uncle Daddy Friend of Fred

    Jan 19, 2012
    Maldon UK
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  3. swivel

    swivel Country Gent

    May 13, 2018
    PNW
    Mix is OK. Bourns, CTS, Alpha are pretty good.
    Yeah, audio tone pots do a lot from 0-4 and little from 4-10
     
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  4. Uncle Daddy

    Uncle Daddy Friend of Fred

    Jan 19, 2012
    Maldon UK
    Does changing the tone cap for a larger value roll off the highs faster?
     
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  5. swivel

    swivel Country Gent

    May 13, 2018
    PNW
    At lower volumes, a .022 cap will retain more highs than a .047 cap. As you near being dimed it matters less. So if you want less highs, yes go up in value for the cap.
     
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  6. Randy99CL

    Randy99CL Synchromatic

    623
    Feb 17, 2020
    Albuquerque
    Yes, you have touched on what I think is the problem; when you use audio taper pots only a small part of the range is usable and it's not linear at all.

    How many times have others written that the volume is inaudible and then a tiny turn later too loud?? Sometimes, even on amps, the volume control should be a linear pot instead of audio taper.

    I'm upgrading the pickups and pots on my Les Paul and today ordered four CTS audio-taper pots from Mojotone. They recommend their "special taper" for both volume and tone.
    From what you've written I'll order two linear tone pots and I can always switch them out if I decide to.

    After I started this thread I also had another idea; I'm going to check the guitars I have and see what taper their tone pots are. It was easier with analog meters when you could watch the sweep of the pointer but even a digital meter will show how smoothly the resistance changes. I checked some audio taper pots today and the numbers jump quickly at first and slow down greatly toward the other end of the sweep.
     
    Last edited: Jul 14, 2020
  7. Randy99CL

    Randy99CL Synchromatic

    623
    Feb 17, 2020
    Albuquerque
    OK I started with the Les Paul that I am upgrading. I put a meter on the stock Gibson tone pots and discovered they are audio taper. The simplest way to verify this was to read the resistance at 0, 2, 4, 6, 8 and 10 on the knob.
    I got:
    0 = 0 ohms
    2 = 220K
    4 = 394 k
    6 = 429K
    8 = 458K and
    10 = 473K

    On 2 the resistance has already jumped to almost 1/2 of the total, wow! And at 4 reads over 83% of the total, that is a great example of non-linear (audio taper). Huge changes in the tone in the first few numbers and very little change after that.
    Then I plugged in the guitar and verified what I had found. On zero the sound is muffled and by 4 almost all the highs are back in, past 5 there is almost no difference.

    I don't like that. I'm going to check my other guitars with pots I can get to (no Gretsches) to get more info but I will order some linear-taper pots and consider them an upgrade in this guitar.
    Once I get it wired up I'll put it through the testing to decide if it was worth the trouble and expense. After all, it may not make any real usable difference.
     
  8. Ricochet

    Ricochet I Bleed Orange

    Nov 13, 2009
    Monkey Island
    If it’s an appropriate value for the pickups and it’s a decent quality pot I’m good.

    Distinguising between LIN or LOG is cool and all, but I don’t play out and there really is no point to obsessively chase any level of consistent roll-off for me. :)

     
  9. swivel

    swivel Country Gent

    May 13, 2018
    PNW
    I actually prefer the jump from 8-10 on a volume pot and use it to good effect. But I like a smooth taper on the tone pot.
    Right now I have one guitar that The tone is best at about 4 on the dial. After 5-6 it isn't much different up to 10.

    I'd like to know how to make that 0-5 scale spread across the 1-10 scale... I think I can add a resistor to a 1/2 value pot (?) but unsure which side of the pot to add it to.
     
  10. Randy99CL

    Randy99CL Synchromatic

    623
    Feb 17, 2020
    Albuquerque
    That is what this thread is about, making the whole tone range usable.
    With the numbers I posted above, with a linear pot I'd get the same tone at around 8 as that one did at 4. The stock (audio taper) pot was only usable from about 0-5 but the linear will be all the way from 0-10.
    To make it clearer, a linear pot has a smooth, even change in resistance as you turn the knob. 2 will be about 20% of the total resistance, 4 will be 40%, 6 will be 60%, etc.

    And you could put a resistor in series with the pickup wire but all that would do is cut down on what the tone pot could do. If you look at the numbers above you can see that once the pot gets to around 400K it's already maxed out and above that doesn't change the sound.
    If you add a resistor, say 250K, that just means the pot would be maxed out at 2 instead of 5.
     
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  11. section2

    section2 Country Gent

    Dec 21, 2016
    Toronto
    It's a matter of taste. I prefer audio taper for both volume and tone.

    With the linear taper tone pots in my 5620, I found that there was no audible change when rolling off from 10 to about 2. Once I got below 2, it was instant mud. I switched to CTS audio taper pots and I'm much happier with them. It's now a smooth transition all the way down: 8 sounds like 80% of 10; 4 sounds like 40%, etc.
     
  12. swivel

    swivel Country Gent

    May 13, 2018
    PNW
    That's the dilemma for sure. Tone pots don't always react as you would expect or the theory suggests. I've had many guitars where what you say occurs: big jump... almost like you might as well have a switch instead. And as you say, a linear can do that too. There's a huge difference in LP wiring when you go to the 50's style, I forget exactly what it was but very different reaction to control adjustments.

    Then there's the issue where a volume pot is fine 1-9 and goes off at 10! I never did figure that one out!
     
  13. section2

    section2 Country Gent

    Dec 21, 2016
    Toronto
    Sounds like someone used a no-load pot for volume.
     
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