alpha or cts?

octatonic

ICBM said:

I still prefer CTS to Alpha - but only if you get specialist-vendor higher-end ones really, the quality of the standard range is shocking now. (They do more than one quality.) They do still feel OK and possibly still sound good (if pots make any difference), but they really are badly made.

Basically this.

ThePrettyDamned

TheGuitarWeasel;166911" said:

EdGrip said:

.... Or I would take people's advice and investigate the Bourns pots (though I seem to remember they were very hard to find and very pricey when I was looking)










It often surprises me that people will spend a huge wad on top notch pickups, then balk at putting top notch components in the rest of the signal path. Bourns are pricey ... but not much more so than 'branded' CTS, and are made to far finer tolerances. True, they are a bit more difficult to track down, but as  @ThePrettyDamned pointed out, Mouser do the full range ... and actually Allparts do a few ... when they can be arsed to keep them in stock

You've got me thinking I might get some for the prs, but I need a blend pot too.

And iI already have a pre wired shugz loom (I need to reflow a joint to the blend pot because it might have been picked up by the dog).

ICBM

EdGrip said:

It's the tolerances bit that confuses me slightly in a guitar-wiring context. Cos, like, who cares? My knobs haven't even got numbers on. I turn it down if I want it quieter and up if I want it louder. When people are discussing the pros and cons of 500k vs 250k, it seems odd to suggest that 250k is correct and, say, 234k isn't - especially as 0k is where the knobs spend most of their time on my guitar.

No, 250K is - assuming you don't play with the guitar muted most of the time .

It isn't the resistance between the in and out that affects the tone, it's the resistance to ground, which is the main load on the pickup.

Still, as mentioned earlier it makes no difference unless you're talking about fairly big changes. You will not be able to hear the difference between a 250K and a 234K pot.

I tested this by using a standard pot, and adding a resistor either in parallel to lower the resistance or in series at the ground end to raise it, with a mini-switch to bypass it, so I could switch the effective pot value on the fly while actually playing, with my head right in front of the speaker . So I'm now very sure that standard pot tolerances do not matter.

imalone

At the high end too? 500k + 20% = 600k which is heading towards amp input impedance territory (though not quite there maybe).

EdGrip

I mean 0k between pickup and output, lots of ks between pickup and ground.

imalone

imalone said:

At the high end too? 500k + 20% = 600k which is heading towards amp input impedance territory (though not quite there maybe).

Obviously posted that too late in the day; as the resistance goes up its effect on the total parallel resistance goes down, so 250k->200k is the most extreme case, which it sounds like ICBM tested.

EdGrip said:

I mean 0k between pickup and output, lots of ks between pickup and ground.

Well, the point is the pot impedance makes a difference to the circuit whatever your volume is, it has a lower impedance than the amp, so determines the load on the pickup even at full volume. See fig 14 of http://buildyourguitar.com/resources/lemme/ for what this does. That's the reason for typically using 250k for single coils and 500k for humbuckers.
The tolerance is for the overall pot resistance, so at 20% (which is common for pots, though most of the ones people use for guitars include 10% ones in their ranges) a 250k pot could be 200k to 300k. There's at least one online shop that does a 300k pot with the argument that this guarantees a higher minimum.
Whether it makes a difference may be down to the cables and pickups involved, but ICBM's test puts it in the ballpark of 'probably not much'.
Edit: fix figure number

Cirrus

Cirrus's anecdotal story;

My most used guitar is a Gibson Explorer that I've jammed, practiced, recorded and gigged loads on since I got it 5 years ago. Last week I replaced the 300k pots that measured between 310 and 320 with 500k pots that read around 510. There is the slightest, most minuscule increase in high end to my ears - I barely notice it and this is on a guitar I know inside out. I'm very confident that a change of 100k or less would be totally inaudible!