Changing taper of 1 meg pot?

[hessodreamy]

I've got 1 meg pots (audio taper, as far as I know, though they're not marked) on my Fender jag and find that the roll of is too sharp. Any tips on altering the curve? Probably placing a resistor somewhere or altering some other part of the wiring that influences volume rolloff?

Sure, I could use 500k pots instead, but I think you'd lose some of the high jag character when the pots are open.

[J M Fahey]

Not sure what you mean by

the roll of is too sharp.

Are you talking about volume or tone pot?
Where on the curve does the problem appear?

* "it does nothing from 3 to 10, all the effect is from 1 to 2" ? or the contrary, seems to do a lot between 7 to 10 and the rst of the movent does little or nothing?

if tone:
* goes from bright to mud without much useful range"?

etc.

Funny to have 1M pots there, would expect closer to 250K in a single coil Fender.

You can measure the pot curve to confirm what you have: momentarily unsolder the hot lead, set pot on 5, you should have 1M end to end (that confirms actual value) and from wiper to each end:
* 500K / 500K if linear
* 100K / 900K if log

EDIT: the so called tricks to alter taper do not really work, or to be more precise, approximate (sort of) a log taper in a linear pot only if:
* it's a conventional volume pot (i.e. does not work on tone)
* it's driven by a low impedance source ... because pot value (besides curve) varies 10:1 , go figure.
Not the case in a passive guitar.

[Mark Hammer]

It,s all in here: The Secret Life of Pots

[eschertron]

Are you playing into a clean amp? If you've got a high gain setting on the amp, the extreme compression through the signal chain will turn your volume control into basically ON/OFF. If anybody has a solution for THAT, I'd like to find out about it

[olddawg]

Are you playing into a clean amp? If you've got a high gain setting on the amp, the extreme compression through the signal chain will turn your volume control into basically ON/OFF. If anybody has a solution for THAT, I'd like to find out about it

Or using a boost pedal or a distortion or both.

[big_teee]

I found this to look at.
My what a complicated beast, for just two Single Coils?
Look at page 5.
http://support.fender.com/service_di...0086A_SISD.pdf

[Mark Hammer]

Pot taper is really a personal taste, and often very much a function of how the individual player tends to use their volume pot. And its pretty much the same thing with volume pedals, and wahs. Some players like to be able to go from full on to full off easily, while others want a volume control that lets them dial in a level just barely under some sort of threshold of another device, or do pinky swells, or compensate for their picking strength that day. And each of those may require a slightly different taper.

Of course, the notion that one can simply look at a catalog, see a taper letter designation (A, B, C, W) and get exactly what they were needing, and expected, when the part arrives, is probably expecting too much, given the tolerances that pots are built to.

So playing around with parallel resistors to achieve changes to taper is probably to be expected, and useful knowledge to have.

[Steve A.]

I have added tapering resistors as well as series as pots to get the desired value and/or taper. To find the sum of two resistors in parallel you take the reciprocal of the sum of the reciprocals. To figure out which value resistor to add to end up with the desired value you take reciprocal of the difference between the reciprocals. If you have more than 2 resistors I start with one pair and keep adding in the others. The formula also works for capacitors in series.
BTW for a tone pot wired as a variable resistor I believe that adding a tapering resistor will create a reverse audio taper. Adding tapering resistors between the input and the wiper as well as between the wiper and the "tail" will create an audio/reverse audio taper (see the link.)

Steve Ahola

P.S. I have a crusade to educate guitarists as to the benefits of a linear taper volume pot. If you are mainly concerned with turning the volume up from 0 (a "swell") then an audio taper volume pot is what you want. However if you are more concerned with turning the volume down from 10 you get much better control with a linear taper volume pot (a reverse audio taper pot might work even better but they are rare- unless you add tapering resistors to a 1M or 2M linear taper pot.)

While linear taper pot are often recommended for guitar tone controls I usually prefer an audio taper for that application so you don't have such a big jump going from 1 to 2. Some guitars come with one of each which I think is really cool because I can just swap them around to get what I want.

While audio taper pots for guitar are very easy to find on-line the selection for linear taper pots is very limited. The first batch I ordered from eBay had 1/4" long bushings which are not long enough to go through the body of something like a PRS SE. The second batch I got had 3/8" long bushings but being Bournes entry level pots they were very loose turning. So I ended up getting All Parts EP-4986 CTS 500k linear taper pots at $4.60 a pop.

I just checked Mouser and I could special order a minimum of 590 CTS pots for $4.62 each. Ouch!

http://www.mouser.com/ProductDetail/CTS/450GT36K504A1S

[potatofarmer]

P.S. I have a crusade to educate guitarists as to the benefits of a linear taper volume pot. If you are mainly concerned with turning the volume up from 0 (a "swell") then an audio taper volume pot is what you want. However if you are more concerned with turning the volume down from 10 you get much better control with a linear taper volume pot (a reverse audio taper pot might work even better but they are rare- unless you add tapering resistors to a 1M or 2M linear taper pot.)

While linear taper pot are often recommended for guitar tone controls I usually prefer an audio taper for that application so you don't have such a big jump going from 1 to 2. Some guitars come with one of each which I think is really cool because I can just swap them around to get what I want.

Absolutely agree. I prefer linear to reverse audio taper, or as we lefties call it "audio taper." For the first couple years I played, I couldn't understand why "0" on my cheap Ibanez's volume pot meant full volume...

For all my guitars I use linear volume, reverse audio tone (since it's backwards a righty would just use regular audio taper). It's been tricky finding reverse audio taper pots with the long shafts to fit in LPs so I've just been wiring the pots in those "backwards"/correctly, with the numbers on the pots running backwards.