Rickresource Rickenbacker Forum

I am wonder what remedies some guitar owners might offer regarding volume pots that are unresponsive until the volume reaches 8-10. An all or none result with little range with regard to volume.

There are solutions on line that address this problem very well. The interested reader, of which I am one, will be well-served in searching out information regarding linear and audio taper potentiometers.

I'm honestly surprised Dane Wilder hasn't chimed-in; he and I had a brief exchange regarding this when he built my harness.
I agree that it is a worthwhile topic for any musician who relies on potentiometers to research.

Thanks Sean. Perhaps Dane will respond.

Stock RIC/CTS pots are audio taper, which is why they respond the way they do. Linear taper pots are more proportional in their response relative to where the knob is at any given time. I prefer audio taper myself for passive electronics, but prefer linear taper for active electronics. Since 99% of the wiring I do is for Rickenbackers,(and because CTS doesn't make a linear taper pot like the one they make for Ricks) I don't have any reason to stock linear taper pots. There is no difference tone-wise between the two types when either one is on 10 or O.

I can't say I understand the logic behind log/audio taper. It doesn't work well in practice. And like Dane said, the result at 100% and 0% is the same, so why bother doing the extra work to make a more complicated taper that is less user-friendly?

cassius987 wrote:I can't say I understand the logic behind log/audio taper. It doesn't work well in practice. And like Dane said, the result at 100% and 0% is the same, so why bother doing the extra work to make a more complicated taper that is less user-friendly?

A nice, even taper comes in very handy when playing like this:



Something i very much like doing with my own playing.

Dane thanks for your comments which are well made. The application I have in mind is more along the lines of the brief video provided by Jeff. The linear pots also seem to be helpful in blending too. As always the application is key.

admin wrote:I am wonder what remedies some guitar owners might offer regarding volume pots that are unresponsive until the volume reaches 8-10. An all or none result with little range with regard to volume.

I came across this explanation on another forum and, more important, the graph which illustrates why a so-called audio taper, or logarithmic, potentiometer gives the perceived result that Peter noted - they are not even logarithmic but rather usually a 2 or 3 line-segment approximation as illustrated in Curve 3 in the graph, which corresponds with Peter's complaint:

QUOTE
"When we buy "audio taper" pots, we usually get something like Curve 3. For less expensive pots, manufacturers use a two or three-segment approximation to Curve 2 [Curve 2 is an actual logarithmic curve]. It's not perfect, but it usually works OK. Curve 4 is the typical resistance versus rotation curve for reverse log pots. In real life - that is, if you ever found one of these in real life - it is usually a two or three segment approximation, too.

If you have an unknown pot, you can figure out what taper it is. You measure the resistance from end to end, then turn the pot exactly to half its rotation and measure the resistance from the counterclockwise lug. The crosses on curves 1, 2 , and 4 show the most probable values. If the resistance is 50% of the total resistance, then the pot is linear. If you measure only 10% to 20% of the total resistance, the pot is an audio taper. If you measure 80%-90% of the total resistance, the pot is a reverse log taper."
UNQUOTE
An excerpt from "The Secret Life of Pots" http://www.geofex.com/Article_Folders/p ... tscret.htm explains why manufacturers use a line segment approximation for so-called audio-taper pots:

QUOTE:
[A] ... linear pot ... [has] a continuous, homogeneous strip of resistive material [a circular band of carbon-containing gunk inside the pot]. That is to say, the wiper [the contact that rotates as you turn the pot knob] traverses an equal amount of resistance in ohms per degree turned. If we wanted to make a non-linear pot, where the amount of resistance per degree turned were not linear, we could mess with the resistive strip to make it nonlinear. This is in fact how it's done. The strip can be made to get skinnier toward on end or the other; a narrower strip has more resistance per unit length and so the resistance per unit degree turned will change. ... We could also change the thickness or composition of the material from one end of the resistive strip to the other.

It turns out that printing a varying thickness is very difficult to do cheaply. Also, varying the composition in any kind of smooth fashion is very hard, not a repeatable manufacturing step. What makers of pots actually do is to use straight-line approximations to a nonlinear resistive curve, and print in sections. For instance, the first 1/3 of the circumference of the pot's resistive band may be printed with one resistive material, the second another, and the third yet another. This allows the maker to come reasonably close to some taper curve.
UNQUOTE

Clement, thanks for finding this information and taking the time to pass it on. Very helpful.

A little late to the party, but here I am, with solution(s) in hand. I wire my pots differently, and I encourage everyone to experiment.

Like many players, I am in the middle: I don't like the all-or-nothing that can happen with pure audio (log) taper pots, but I want a little more control in the response up in the curve than linear taper pots give. So here is what I do:

I make a hybrid curve pot by jumping the wiper and output lugs of a 500 kohm pot with a 1 meg resistor. As we all know ohm's law, this gives the equivalent of a 333 kohm pot, which is current RIC production spec, but with a hybrid curve or sweep since the 1 meg resistor is always "on." I have done this on every guitar and bass I own, except for my 4002 bass, due to its rather comparatively complex wiring. It works for both single coils and humbuckers, although for humbuckers you could go to a 1 meg pot with a 1 meg bridge resistor to keep the brightness up, as that produces effectively a 500 hybrid kohm sweep. Conversely, you could take a 500 kohm pot and a 500 kohm bridge resistor to get a hybrid 250 kohm sweep, if you want to take a little bit of the edge off, especially in the neck position.

I have found on stage that this buffers the "all-or-nothing" that an audio taper pot can sometimes do, but keeps a good degree of control in the upper part of the curve, where most of us tend to keep our controls when, for example, tempering between rhythm volume and lead volume.

And if a player wants to keep the top end sparkle in addition to jangle, then like all the Tele and Strat players, the .001 treble bleed capacitor can be installed at the same time.

iiipopes wrote:I make a hybrid curve pot by jumping the wiper and output lugs of a 500 kohm pot with a 1 meg resistor. As we all know ohm's law, this gives the equivalent of a 333 kohm pot, which is current RIC production spec, but with a hybrid curve or sweep since the 1 meg resistor is always "on." I have done this on every guitar and bass I own, except for my 4002 bass, due to its rather comparatively complex wiring. It works for both single coils and humbuckers, although for humbuckers you could go to a 1 meg pot with a 1 meg bridge resistor to keep the brightness up, as that produces effectively a 500 hybrid kohm sweep. Conversely, you could take a 500 kohm pot and a 500 kohm bridge resistor to get a hybrid 250 kohm sweep, if you want to take a little bit of the edge off, especially in the neck position.

I forgot all about this, but indeed, you told me about it when I was playing some of your instruments and I do seem to recall a nice even taper the volume on your custom P Bass.

I just found an old NOS Mallory 500KΩ potentiometer in its original box. How much could this sell for? It was in a box with some vintage (1960s) RCA and Tung-Sol preamp tubes and a pair of RCA 5881 tubes that I also have.