Electronics > Projects, Designs, and Technical Stuff
Logarithmic pot
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SiliconWizard:

--- Quote from: TimFox on January 06, 2020, 04:09:56 pm ---Another advantage of using a resistor-loaded linear-taper pot is when you have multiple controls and want them to track each other closely, trading off absolute log accuracy.  A good linear pot will be more reproducible from unit to unit than most log pots.

--- End quote ---

Yup. In a lot of applications (especially audio), exact log is not critical anyway. And if you think a typical "log" pot will match a log function better than the above, you could be in for some surprise as well... unless you buy very expensive shit.

Audio applications in which it could be a bit more problematic is the typical large linear pots (not in the sense of linear vs. log, but in the sense of linear vs. rotative) used on studio mixing consoles, as accuracy for a given position could be a bit more important there. But that said, even on analog consoles, it's not uncommon to see linear pots controlling VCAs with a log transfer function anyway... so...

In any case, it answers the OP's question fairly well, and is actually used in real products and is not just a thing for hackers.
akis:
Can't shunt to ground with passive guitar pickups, the pots need to have many hundreds of KOhms. Typical passive pickups pots are 500K. If you shunt this with say a 100K resistor, you'd be dropping the value seen by the pickup to <100K, and then you'll lose the high end.

While the standard audio guitar pots are "OK" for the volume control, they are wholly inadequate for the tone control circuitry, as I recently found out. On the tone control it all happens between 0 and 4, with the range between 5-10 being inconsequential. That is where adherence to the true power function would provide a more gradual tone response.
dmills:
For volume controls the Baxandall volume control circuit is reasonable if you can tolerate an active device to do the buffering and the tendency of the law to fall to bits at the very low end. Uses a linear pot too, which is helpful.

Regards, Dan.

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