Only that getting a pot that’s been “certified for guitar” matters - apparently, the performance of pots can range widely vs their rating. Buy from a music/ guitar site that discusses measuring them without too much bull in their pitch. I think I used StewMac and RS Guitarworks on mine…
One thing I’ve noticed, working on amplifiers, is that all pots are not created equal when it comes to keeping the gunk on the outside where it belongs - this is not a place to shave pennies. Many pots in American gear are made by Alpha and CTS, and those are fine, but if you want to move up, you can look for some “MIL-SPEC” pots of the same value, and those, regardless of manufacturer, should be excellent.
500K MIL-SPEC pots it is!
Yeah, I’ve noticed that $$=value with electronics, especially if there are moving parts like pots and switches. Quality control is ultra-important and for the most part, that costs money. I’m looking on the internet now for military spec stuff; I wonder if my old haunt in Orlando, Skycraft Surplus, will ship them to me…
Looks like Skycraft might not be exactly the place it was 20+ years ago hehe butI found a couple of places online that fit the bill. Looks like I’ll prolly end up with an Alessandro pot for about $15; thanks for the recommendation, EtF!
First of all, please note that I know NOTHING about electronics. The biggest issue for a pot to be used on a guitar is that it is “old tech.” Meaning: old, inefficient potentiometers based on the types built in the 1950’s. My point was that the performance of these old-style pots can vary widely, so make sure you get one that is reasonable “in spec.”
If that type of mil-spec pot achieves this, cool. If that type of pot is a newer design, it may be perfect for an amp, but you would not want it for a guitar. I am not sure how to describe the science, but the experience of it is very clear: newer designs have a “tigher cutoff” - when you dial up the pot, the parts of the signal cut off is efficient. With the older designs, they are apparently more inefficient, so there is a bit of “leakage.” It turns out this form of leakage is pleasing to our ears - it dampens bad harmonics but even-ordered harmonics remain.
If you are a knob twiddler, as you know I am, this type of pot is essential. Guitars with bad/new-design pots often sound like ass if you dial down the Volume or Tone. It’s a crime, especially if the guitar is one that really benefits from knob twiddling, like Teles or P-90 equipped guitars.
Tell me more about pots!
I have a 65 Jazzmaster and 90’s Alvarez bass both with bad pots. Yes, I’ve tried cleaning them out with deoxit, no dice.
The Alvarez is a cheapie but nice bass. No idea what type pots or anything.
The Jazzmaster is a player, not a collector’s item; replacement neck, repainted, etc., but sounds super. You may consider this heresy, but I had it rewired to not roll off treble when volume is turned down.
Am I going to lose the great tone if I repot? I’ll have a good tech do it; my iron (or perhaps my technique) isn’t up to soldering the ground to the pot housing.
As it is, most of the volume change is at the bottom. I think players who pinky the knob like that, and it’s OK with me.
Any suggestions or warnings?
PS: moving to Seattle, know a good tech there?
I think what you are trying to say is to make sure that a logarithmic pot is used for volume, as opposed to a linear pot. Our ears are irregularly shaped cones, after all (remember rate of change stuff from high school calculus, anyone?).
Sir, what can we do? You have my understanding of the need for old-design pots that have been measured to ensure they are within spec. Beyond that, the circult you choose to insert them into is a whole 'nother question. If you like your circuit, who cares what anyone else thinks? Be happy! Now, would a better pot help? It could. The tricky thing with all components is do you “like how they are inefficient”. If you like your current sound, then some of the inefficiencies in your components work for you. Avoid replacing stuff that isn’t broke!** But if you get a good, musically-inefficient pot put in a circuit you know you like, I suspect it would be a good thing.
**ETA: or is broke the right way! 
Yes, it should be a log pot, but no, I am saying that log pots made “back in the day” where “musically inefficient” and often not really calibrated to spec. So find one with that old design that is also calibrated.
Ah, ok. YMMV but I’d rather not rely on or try to find something that was poorly made due to inefficient processes or irregular materials or something. I’ll just find the best designed, best made pot I can and go with that.
I also don’t deliberately use analog equipment; I don’t think “it just sounds better”. YMMV.
All good. And since you want to sound like “Satan trapped under a lawnmower” (still best description ever) you are playing with a lot more distortion than I am anyway so have different needs.
Just for the record, if you’re dealing with potentiometers, AT = Audio Taper = Logarithmic = Log Pot. I’ve never seen them referred to as “logarithmic” before, but it’s been a while, and that is what they are.
As for difficulty soldering to the shell of a pot, the key is to clean the surface. At least use a pink rubber eraser. A small wire brush can work. Or emery cloth, but not the super fine grit.
Yep, audio taper. Like I said about me and electronics… I just know I was surprised at how this is one of those things that matters with regards to your overall tone, especially if you use them. It makes sense that it does matter, but there is so much noise on the internet.
I’ve been thinking about what this post means, since a lot of it didn’t sound really familiar to me, and since I’m a bit of a pot head (nyuk nyuk), I don’t think it was time wasted.
(We’ve now reached the part where I started typing a treatise on the history and varieties of the potentiometer, and, almost putting myself to sleep, thought better of it. Suffice to say - )
What I think you want is a pot that’s made by carbon composition, and that is also true logarithmic (instead of quasi-logarithmic), and within 5-10% tolerance. The ‘carbon composition’ part may or may not be important, but it was the way guitar volume pots were made in the good old days, and probably all pots which are destined for use in guitars still are still made this way, so OK.
One way to make sure you’re NOT getting a true log taper, <10% pot, is to buy a cheap pot, since quasi-log, high tolerance pots are cheaper to make. So again, I’m betting that a MIL-SPEC, carbon comp, log taper pot would be - like nuking the planet from orbit - the only way to be sure.
And, having played a (my surprisingly great-sounding) '73 Strat through an Alessandro Working Dog amp (an act which led to considerable groveling and piddling) I’d have few reservations about recommending his pots, rebranded though they may be.
Aye, all of the guitar pots I’ve ever seen are carbon pots. Some differ on the post/wiper construction (brass, steel, aluminum, etc.), but the resistive element is always carbon of one sort or another, usually graphite.
That sounds better than anything I could articulate! Thanks!
Another pot head! If I see you on the highway, I’ll give the secret hand signal.
It felt just like translating the Dead Sea Scrolls, only more important, and from a higher authority.
Too funny.
One thing to be aware of is size wrt to pots. The mil-spec PECs I ordered from digi-key were larger than the standard Alpha/CTS pots. This made a big difference in my tele where space was tight. The other thing is that super tight tolerances aren’t always a good thing. An electric guitar and amp are fancy audio distortion generators and if you were to build them with audiophile grade components you will get super clean cleans, but dirty,nasty distortion is going to be in short supply.
You probably won’t hear much of a difference swapping pots (unless you drastically change values) unless they ones you have are pooched, the single biggest change you make to any electric is going to be the pickups.