Pot types - which is which?

[djwackfriz]

Note: answers such as "Maui Wowee" or "Jamaican Redhair" are not helpful!

OK, so instead of working on my dissertation this weekend, I have been learning about pots, caps, and the various effects of both on a bass' tone. One thing has me lost, though, despite a rigorous search of the TB archives...

Which pots are for volume, which pots are for blend, and which pots are for tone!?!?

On Allparts, I see things like "audio taper pot", or "linear pot"... what the hell does this mean? Ideally, I'm looking for 500K volume pots, 1 Meg-ohm tone pots and 1-Meg blend pots. Can anyone explain how to tell which is which? I majored in literature, which helps very little in this case...

[djwackfriz]

Originally Posted by GlennW

You'll want audio taper for volume and tone - the blend pot will likely be whatever it is.

You can use the search function if you're curious as to what's what.

Cool! Thanks for the info, that helps me out a lot!

... Actually I think I understand why this is, now that I think about it... Audio taper is (pardon my lack of jargon) essentially adjusting the amount of "stuff" moving through it from a given output source. For the volume pots, it's each pickup that is the output; for the tone, it's the other two pots that are the outputs. The caps, then, adjust/cut off the high or low regions of the stuff before it gets to the pots.

Yes?

[basadam]

A "linear taper" pot, will equally increase and decrease volume (or tone) as you turn it. A human ear has problem hearing this correctly, thus "audio taper" pots were born. With and "audio taper" pot, as you move from 0 to %90 the volume increase is minimal, from %90 to full there is a sudden increase.

Originally Posted by GlennW

You'll want audio taper for volume and tone

This is the standard treatment for most guitars and basses, however I'm planning on experimenting with a linear pot, because I'm beginning to think audio-taper pots prevent me from mixing the two pickups of a J-bass the way I want.

As for the original question; a "pot" can be used for both volume and tone, and the value (250K, 500K, 1M) is purely personal preference. As a general rule, the more resistance value the more treble available. The industry standard is 250K for single and split coils, 500K for humbuckers.

A blend pot is nothing more than two-pots combined. A 500K blend pot is actually two 250K pots. In center position both pots are full-on, as you move towards one side, the other side's volume is decreased.

[Pbassred]

The human ear percieves volume changes in a logrithic way. I.e to percieve double the loudness you need 10 times the power. 3000Watts is only twice as loud as 30Watts!
You volume pot start with a tiny change per degree of turn, but at the end of its travel it make a massive diference per degree.

pickup balance need "linear" pots. The rate of change is constant per degree of turn. If you drew a graph of angle against resistance it would be a straight line -hence "line-ar".

The earlyer posters believe that tone pots should be Log too. Some people don't. Its a matter of taste.

I never heard of "linear taper" before. Must be an American thing.

[basadam]

Originally Posted by Pbassred

pickup balance need "linear" pots.

What about these: http://www.basspartsresource.com/ele..._blendpots.htm

I never heard of "linear taper" before. Must be an American thing.

Nope; I'm not American!