Are these audio or linear taper pots?

Lester

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I put some new pots in a mod project. They are supposed to be Bourne Audio Taper, but they seem to act a little oddly, so I thought I'd check by measuring the resistance through the cord (everything is installed at the moment). Seemed like it would be easy to tell but I've never done this before.

I expected to see readings that made sense, but clearly there must be some electronic interaction that changes the readings in a way I don't understand. To confirm the oddness, I measured my LP and it gave a similar odd scale.

So, I'm back to the question: Are these audio pots?

250K pots, two pickups, toggled to neck only position, single coil, tone control switched out (push pull), readings on higher DVM scale so figure +/- 1K with round off error:

Vol Control Setting - Resistance reading
10 - 5.4K
9 - 11K
8 - 67K
7 - 66K
6 - 25K
5 - 20K
4 - 16K
3 - 10K
2 - 7K
1 - 1K
0 - 0K
 

ARandall

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Readings in circuit are borderline irrelevant.
Measure them with no solder connections on.
 

Lester

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Readings in circuit are borderline irrelevant.
Measure them with no solder connections on.
-Enter Mr. Bill from vintage SNL - Nooooooooooooooooooooooooooo!!!!

Yeah, I thought of that, but these are mini pots with tiny little lugs... had to use 22G wire just to get through the lugs. Real PITA to work on. Was hoping to avoid that.
 

Lester

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OK, new measurements with pot out of circuit:

10 - 271K
9 - 268K
8 -192K
7 -109K
6 - 31K
5 - 24K
4 - 19K
3 - 13K
2 - 8K
1 - 2.5K
0 - 0K

Audio? Odd taper or is the big jump around 6 to 8 normal?
 

strayedstrater

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Audio.

The values are pretty normal. Logarithmic is exponential, so there are small increases at the low end and big increases at the upper end.

With log pots, half volume (5) should be about 1/10 (10%) of full volume (10), so all the readings below 5 will be tiny and above 5 will be big jumps. With linear, half volume would be around 1/2 (50%) of full volume.
 


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