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Audio taper vs. linear pots

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  • Audio taper vs. linear pots

    Can someone explain the difference in simple english?
    If man evolved from apes why do we still have apes?

    Lost from EBassist

  • #2
    Can someone explain the difference in simple english?


    I'll try:


    In a linear taper pot resistance changes directly proportional to the wiper position. So, say, a quarter turn of the pot will result in the same change in resistance no matter where in the travel of the pot you are. So in a 10k pot a quarter turn always equals a change of 2500 Ohms. In an audio taper pot the change in resistance per portion of turn is not linear. So at the low end of the scale, a quarter turn on a 10k pot might mean a 100 Ohm change in resistance, but at the high end a quarter turn might mean a 1000 Ohm change in resistance. The resistance change per unit of shaft turn is logarithmic in an audio pot. It's done because what our ears perceive as linear changes in sound level are actually exponential changes in signal level. Audio taper pots help match the behaviour of electronics to how our ears respond...

    Did that make any sense?
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    • #3
      Here are a linear and log graphs together.

      Audio taper pots have a log curve while linear pots have a, well, linear curve.

      Since audio volume also has a log curve, you need a log pot to hear volume opening progressively.
      Long story short, use linear when dealing with information (like for an active preamp) and audio taper when dealing with actual audio signal (like a passive volume).
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      • #4
        Thanks guys. Kinda makes sense. The reason I am asking is because of the tone control on the Darkstar'ed P bass that I just got. If you have the tone control rolled all the way off the tone is dark as it should be. When rolling it to the treble side you barely move it and you start getting treble and it is full on at about 1/4 turn. The rest of the sweep is all the same. And it is very, very bright. In other words the first 1/4 turn rolls all of the treble on. Does that make sense?
        If man evolved from apes why do we still have apes?

        Lost from EBassist

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        • #5
          Thanks guys. Kinda make sense. The reason I am asking is because of the tone control on the Darkstar'ed P bass that I just got. If you have the tone control rolled all the way off the tone is dark as it should be. When rolling it to the treble side you barely move it and you start getting treble and it is full on at about 1/4 turn. The rest of the sweep is all the same. And it is very, very bright. In other words the first 1/4 turn rolls all of the treble on. Does that make sense?


          Yup, makes sense. Whichever taper you've got there, you want the other one (I'm being non-specific, because depending on the circuit used, the behavior you describe could be due to either using a linear pot where you want a log pot, or vice-versa).
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          • #6
            Is there a way to tell which one I have? Are they marked in some way?
            If man evolved from apes why do we still have apes?

            Lost from EBassist

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            • #7
              On the back of the pot it will sometimes say "audio", "log" or "A". These are all audio taper. "linear", "lin" or "B" are all linear taper. You can also try looking for a wiring diagram or parts list for your specific model and year of bass, but that's dodgy (specs can change mid-year and not be listed, etc)
              Yamaha BB404Fender Mexi Jazz, customizedYamaha TRB-1005Fender Highway-1 Strat, customizedEpiphone Les Paul, Worn BrownTakamine Jasmine acousticTaylor 114ce acoustic/electricPeavey 210TX+ext 2x2x10 comboFender Bassman 150 1x12h comboWhen shopping for an axe, you will probably find yourself negotiating with your checkbook. This is normal, but do refrain from talking to it out loud.

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              • #8
                Thanks guys. Kinda makes sense. The reason I am asking is because of the tone control on the Darkstar'ed P bass that I just got. If you have the tone control rolled all the way off the tone is dark as it should be. When rolling it to the treble side you barely move it and you start getting treble and it is full on at about 1/4 turn. The rest of the sweep is all the same. And it is very, very bright. In other words the first 1/4 turn rolls all of the treble on. Does that make sense?


                You have a linear taper tone pot and want an audio taper tone pot. You aren't getting full treble at 1/4 on, but it is close. This configuration allows much greater control for fine tuning the treble. Switch to an audio taper if you want a more traditional tone control.
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                • #9
                  You have a linear taper tone pot and want an audio taper tone pot. You aren't getting full treble at 1/4 on, but it is close. This configuration allows much greater control for fine tuning the treble. Switch to an audio taper if you want a more traditional tone control.

                  Thanks Kindness. Why would anyone want to use linear tapers? I mean you have such a small window to adjust.
                  If man evolved from apes why do we still have apes?

                  Lost from EBassist

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                  • #10
                    Thanks Kindness. Why would anyone want to use linear tapers? I mean you have such a small window to adjust.


                    I use them on passive jazz basses. I love the control it gives me over subtle treble cuts. I have little use for fully rolling off the tone control on a passive jazz, but I like to take a bit of the edge off sometimes. That's it's most useful application.
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