Pot values with diff't pickup types

[Jake]

So, I did a pot swap on my 72 Tele Deluxe reissue last year and it sounds like a new guitar. Fender shipped them with 250k volume pots, which led to a rather dark and muddy tone. With a swap to 500k volume pots, it's a huge difference.

I understand that 250k are good with single coils and 500k or 1meg are good with humbucks, so what is a good match for a P-90? Does the resistance of the tone pot come into play as well? Do all these things vary with each pickup manufacturer?

[VOLVO)))]

Pots are really just variable resistors. From 0-250k, from 0-500k. Think about it in terms of range, if you turn the volume knob half way up on a 250k pot you're getting 125k ohms worth of resistance. If you turn it half way up on a 500k pot, you're getting 250k ohms, the full range of the 250k pot itself. 500k is the way to go with most anything, unless you want to tame certain frequencies. I use 500k pots with HB's, and single coils. I'll use 250k pots in basses, if that's any indicator of what they do to sound.

P-90s are just really large, powerful single coils. That's why they pick up the 60 cycle hum, just like single coils... That's also why they go microphonic really easily, compared to humbuckers. Single coils usually get wound around 7k, and that's hot for a single coil. P-90s can range anywhere from 7k to about 11k before sounding similar to a humbucker.


TL;DR - Use 500k pots

[Hemisaurus]

If you ground the other end of the volume pot, which a lot of folk do (myself included), then they are always across the pickup, so the total value does come into play a bit. If you add a tone pot, then you've halfed it again. Two 500K pots are now a 250K load, two 250K pots are 125K, you're average amp has a 1M input resistance, so you are dumping four times the pickup signal through the pots.

That said, some people maintain that pickups are designed with this loading down in mind, indeed some manufacturers specify which value of pot to use. If you worry about it, someone posted a link in a similar thread, only a few months back, mentioning no load pots, which click at the full on point to takethemselves out of circuit.

[VOLVO)))]

It was E9th, and those are Fender pots. They eliminate themselves from the circuit at full bore.

[Baltar]

My buddy back in Detroit, has an original '73 Tele Deluxe.  I swapped out the 500K's for some 1Meg's and it made a world of difference.  He's a real knob-turner though and uses them a lot.  We also did the treble-bleed mod to all of our guitars and that was another cool trick if you're going to use the volume control for different tones.

[Instant Dan]

I found the Seymour Duncan 'JB' works better with 250K pots than 500K. No icepick mids.

[Hemisaurus]

You know, you don't have to put any pots on atall, if you don't want to. I ran my bass neck pickup to the jack for several (gigging) years.

Sunn, how do those no load pickups work? I've seen online guides where people are making them by either scraping the carbon off the pot track, or insulating it with varnish, neither makes electrical sense. If you scrape of the carbon, you've broken the connection to ground, you can achieve the same by not grounding the end of the pickup. If you varnish the track, the wiper isn't making contact, but it's still across the circuit.

As I think about it, it is possible to wire a guitar with neither pot across the pickup, without having to resort to no load pots. Take a pot, pin 1 is the top of the resistance, pin 2 is the wiper, pin 3 is the bottom.

Take the output of the pickup selector, to pin 1 on the volume pot, connect pin 2 of the volume pot to pin 1 of the tone pot, connect your tone cap between pin 2 of the tone pot and ground, connect the output jack to pin 1 of the tone pot.

Neither pot is connected to ground on pin 3, at the full on position inside a pot, the wiper makes contact with the metal of pin 1, so no load.

No idea if this would be noisier, but it would make the circuit like Sunn said, just variable resitances between the pickups and jack.

NB you can still use the case of the pot as a grounding point, just don't connect pin 3 to he case.

[Hemisaurus]

Err the above would mean the tone pot is wired backwards, which for me sounds good, but others may object

[VOLVO)))]

They just eliminate the path to ground, which sounds like it would increase noise. Honestly, i feel like it's just splitting hairs at that level. If you want maximum output and maximum control, make the circuit as simple as possible. Pickup > volume control > jack. Just like 90% of my axes. Total resistance plays an overall roll. If you want to tame highs use 250k pots... maximum output... use 1m, sice you will end up with 500k worth of resistance in pots alone.

[Hemisaurus]

I wonder if I should just fit a tone switch, rather than a tone knob. I usually have it all the way down (full treble bleed to ground) and when I don't it's all the way up. I could fit a multi-position switch, and put different cap values on each, and that would probably have a way more dramatic effect, than a pot > cap > gnd.

Think more Orange FAC than Gibson Varitone, as the Varitone uses caps and resistors in each tone setting, the FAC is just a cumulative series of capacitors.

[VOLVO)))]

Miniswitches are far more functional than knobs imo

[Hemisaurus]

I'm not drilling out my bass to put six miniswitches on it

[VOLVO)))]

Do it to a pbass haha