Time to replace my guitar volume control?

[Mark Hammer]

Ok OK OK, now *I* get it too.    You'll forgive me if that horse appeared to not be quite completely dead and I was standing there with a perfectly good stick in my hands.

The simplest, and cheapest in-a-pinch cure is to pry the tabs up, lift the back off, and brush the resistive strip with a cotton-tpped applicator, like a Q-tip.  If you have some alchohol to do it with, great, but you can do it dry too.  You should see a bit of black crud on the cotton when done.  Put the cover back on and pinch the tabs shut.  they're usually good for at least 3-4 openings and closures, provided you're gentle.

I buy those applicators at the dollar store for a buck for a few hundred.  Doesn't get much cheaper than that.

[edvard]

More like somebody shot the horse and then pointed the other way and shouted "Oh look... Unicorn!!" 

Like I said, the pot sounds a little better after shooting it with some of that tuner cleaner stuff they sell at Radio Shack.
I've heard others say it works well because it incorporates not just cleaner but some sort of foaming action to lift the grime and a touch of lubricant to help the wipers sweep it out of the way.

My original question has to do with the fact that I ONLY get hiss/crackle at the 3 and 9.5 positions.
I SUSPECT this is because what we commonly accept as 'Audio Taper' pots aren't a true taper but two different resistive values tacked together, as explained in the "Secret Life of Pots" article, and the wear is happening at the joint... I think... which is why I asked....
I had never experienced this before and found it as interesting as I did annoying.

The second part of my question had to do with another part of the "Secret Life of Pots" article; that a high-value pot and 1/4 - 1/6th value 'tapering resistor' would give equivalent or better performance.
At the very least, it *should* wear more evenly, correct?

... Then I take a step back and look at the whole thing again and find myself asking "Why is this even important? Why do I want to know? Why don't I just clean it or replace it and just go about my day?"

Keep your horse-beatin' stick, Mark; it's a dirty job but someone's gotta do it...

[Mark Hammer]

Keep your horse-beatin' stick, Mark; it's a dirty job but someone's gotta do it...

Just as an aside, when you have a chance, open up a standard 16mm Alps-type pot, and a larger-diameter one.  You'll see that the wipers can have physically different properties.  Larger pots have wipers with more "fingers", that can be shaped sort of like 4-5 rounded knuckles, carressing the surface of a much wider resistive strip (i.e., more places to maintain electrical continuity in case one of the "knuckles" breaks contact).  In contrast, smaller pots can have wipers that are more like 3 thumbnails scraping a much narrower resistive strip.

The tendency is to always want to go with a smaller pot because of what it affords in terms of spacing convenience, but there is a great deal to be said about larger-diameter pots when it comes to long-term functioning.

[edvard]

Oh, yes I have done that, and have since then tried to use 24mm Alpha pots whenever I can get away with it.
Which usually means no 1590B builds... 

I have even found a few older ones that use a solid hunk of conductive wiper element similar to the carbon-rod "brush" on larger electric motors.
I imagine that one may still be good... 

[edvard]

I figured out the noise was either caused or made worse by my brilliant idea of using a PNP emitter-follower buffer at the head of my circuit.
NPN and FET buffers made no noise at all (well, FET buffer made it squeal a bit...)
Wonder why that is?
New discussion here:
http://www.diystompboxes.com/smfforum/index.php?topic=90093.0