log or lin pots test

phil_b

i found some 250k cts pots in my bits box but im not sure if the are log or liner. the markings on the back have been soldered over.

is there an east way to check

Roland

Turn it to halfway. If the resistance is 125k then its linear

Almach

OK smartypants, what would it measure if it is log ?

Almach

CTS have a data sheet for their 450G range of guitar potentiometers. It has a graph of the resistance curves.

Roland

Almach said:

OK smartypants, what would it measure if it is log ?

That depends on how it’s made. There’s a theoretical value, but different manufacturers and production methods diverge from that. However if the resistance is 50% at halfway then you know it’s linear.

ICBM

What Roland said. There's more than one log taper - true log is 10% of the value at half turn, but there are other specifications which are usually called 'log (%)', or more strictly 'audio taper' - and some lower-quality ones aren't any proper log or audio spec.

But if you set the pot to halfway and you get half the overall resistance from the middle terminal to each end, then it's linear since none of the 'log' tapers are anywhere close to that.

phil_b

well what ever one it is the volume only seems to work between 6 and 10 below 6 and it silent

ICBM

phil_b said:

well what ever one it is the volume only seems to work between 6 and 10 below 6 and it silent

That and the fact that it's entirely covered with solder would indicate that it's probably been buggered by overheating.

phil_b

ICBM said:

phil_b said:

well what ever one it is the volume only seems to work between 6 and 10 below 6 and it silent

That and the fact that it's entirely covered with solder would indicate that it's probably been buggered by overheating.

Maybe

@ICMB ;; I just made my self a pickguard that has 2 pickups with a single volume and single tone. If I order new pots should I get log or lin?

ICBM

phil_b said:

@ICMB ;; I just made my self a pickguard that has 2 pickups with a single volume and single tone. If I order new pots should I get log or lin?

Log or Lin for volume depending on your preference - Log gives a fast drop-off from full, good for cleaning up an overdriven amp; Lin gives a smoother roll-off better for use as an actual volume control. Log for tone, always - unless you want all the sweep in the bottom quarter turn for 'hand wah' type effects.

phil_b

ICBM said:

phil_b said:

@ICMB ;; I just made my self a pickguard that has 2 pickups with a single volume and single tone. If I order new pots should I get log or lin?

Log or Lin for volume depending on your preference - Log gives a fast drop-off from full, good for cleaning up an overdriven amp; Lin gives a smoother roll-off better for use as an actual volume control. Log for tone, always - unless you want all the sweep in the bottom quarter turn for 'hand wah' type effects.

thanks for the explination