Potentiometer Actual Tapers

[pablogilberto]

Hello!

I have read that Audio/Log tapers are actually not perfectly logarithmic in nature.
During manufacturing, what they do is create several linear tapers with different slopes in order to approximate an Audio/Log curve.

That is the main reason why Audio/Log pots of different brand/makers and models differ.

I'd like to ask for your help on how to measure the actual taper of potentiometers so I can compare them side to side.
I mean, some experiment/measurement technique that will record the resistance (or voltage maybe) as I sweep/turn the knob of the pots.

What setup can be done to perform this?

Thanks!

[newey]

I have read that Audio/Log tapers are actually not perfectly logarithmic in nature.
During manufacturing, what they do is create several linear tapers with different slopes in order to approximate an Audio/Log curve

Yep. See: ChrisK's "Audio Taper Pots- Not Really"

As for measuring the differences, the only thing I can think of is to just do manual resistance measurements, with the pot at "10", "9", "8", etc., then plot the results for various pots to compare one to another.

[thetragichero]

i suppose sweep matters in a macro sense for our purposes inside guitars but in the micro sense i have quite a few instruments with no numbers on the knobs and even on my strat i don't look at em. i generally set them by sound

[ashcatlt]

The fun part about a continuously variable potentiometer is that there are only two easily and precisely repeatable positions. Everything in between is subject to slop and error. I would not be surprised if that error added up to about the same amount of deviance we’d see between a “real” log curve and the piecewise linear approximation. It won’t tell you much about one pot and will tell you even less about comparisons between multiples.

IF one had some way of turning the pot either in steps that are truly repeatable between modules OR at a known constant velocity, one could run something through it, do that while recording the output, and see the difference.

I agree it’s not really worth it. Like I said in your other thread, they all have the same ratios available and taper has literally no effect on tone. Does it matter so much to you whether a given value is at 6.8 on the knob rather than 6.6? Can you reliably hit 6.8 rather than 6.7? The only time it might have a meaningful impact is if you rely almost completely on volume swells so that the feel of the pot in motion is more important. One usually just kind of learns the pot and adapts their “style” almost instinctively unless it really is just the wrong taper for the job.

[thetragichero]

Jan 27, 2020 13:30:51 GMT -5 ashcatlt said:

slop and error

ahhh so you've heard me play!