1 meg pots and TB Plus pickups

georgestrings · August 02, 2016, 06:07:15 AM

Has anyone tried this combination? - If so, what were the results? I dig the way my Gibson basses look and play, but would like the stock pups to sound a bit brighter and clearer - a little increased output wouldn't hurt, either...

- georgestrings

Basvarken · August 02, 2016, 06:22:06 AM

I don't think choice of a different potentiometer would increase the output.

georgestrings · August 02, 2016, 09:14:53 AM

Quote from: Basvarken on August 02, 2016, 06:22:06 AM
I don't think choice of a different potentiometer would increase the output.

I have read that going from 500k pots to 1 meg pots will bleed off less treble, and sometimes allow slightly more output - but I have no direct experience with this...

- georgestrings

amptech · August 02, 2016, 10:13:26 AM

Quote from: georgestrings on August 02, 2016, 09:14:53 AM
I have read that going from 500k pots to 1 meg pots will bleed off less treble, and sometimes allow slightly more output - but I have no direct experience with this...

- georgestrings

Slightly more treble if you use 1 meg (or just make your tone pot a 'no load on full' pot by scraping away the end of the resistance track) is possible, but i would not worry about doing this if more output is the goal. The pickup impedance is so much lower than the resistance of the harness/loom so that is mainly what the amp will see.

Just bypass the circuit and run the pickup(s) directly to the amp, and see if it's worth doing something.

georgestrings · August 02, 2016, 11:27:48 AM

Quote from: amptech on August 02, 2016, 10:13:26 AM
Slightly more treble if you use 1 meg (or just make your tone pot a 'no load on full' pot by scraping away the end of the resistance track) is possible, but i would not worry about doing this if more output is the goal. The pickup impedance is so much lower than the resistance of the harness/loom so that is mainly what the amp will see.

Just bypass the circuit and run the pickup(s) directly to the amp, and see if it's worth doing something.

More treble is definitely the motivating factor in this - I'd probably just run straight into the jack, except I want to keep the ability to blend pups, or completely roll off both in certain circumstances... Thanks for the input,

- georgestrings

Dave W · August 02, 2016, 01:27:03 PM

Going to a 1 meg pot won't change the output, and it won't be any brighter than a 500k pot with it turned up all the way. The change will be the point at which it starts to roll off high frequencies as you turn it down. Unfortunately, with some pickups a 1 meg pot acts almost like an on/off switch rather than a gradual rolloff. I don't know how the TB Plus would react.

Granny Gremlin · August 02, 2016, 02:23:48 PM

+1 to Amptech - try it straight to jack and see. Sometimes, additional treble can increase clarity and give the illusion of higher output.

georgestrings · August 02, 2016, 02:26:02 PM

Quote from: Dave W on August 02, 2016, 01:27:03 PM
Going to a 1 meg pot won't change the output, and it won't be any brighter than a 500k pot with it turned up all the way. The change will be the point at which it starts to roll off high frequencies as you turn it down. Unfortunately, with some pickups a 1 meg pot acts almost like an on/off switch rather than a gradual rolloff. I don't know how the TB Plus would react.

I appreciate your thoughts on this, but think you may be mistaken regarding tonal changes - for example, one typically uses 250k pots for single coil pups, and 500k for 'buckers - and from everything I've read, that's because of treble differences between the two pup types... I'll admit that I don't know this for sure, but there's a fair amount of info "out there" on this stuff, and it all seems pretty consistent...

- georgestrings

georgestrings · August 02, 2016, 02:33:46 PM

Quote from: Granny Gremlin on August 02, 2016, 02:23:48 PM
+1 to Amptech - try it straight to jack and see. Sometimes, additional treble can increase clarity and give the illusion of higher output.

Thanks - increased clarity/brightness is what I'm after most of all... I've considered going "no load", but can get the 1 meg pots a bit cheaper - and *think* they may make the difference I'm looking for... I figured I'd ask this forum, since there are plenty of people here who have experience with TB Plus pups - since I'll do the work myself, it really won't cost me much to swap both of my Gibson basses over...

- georgestrings

georgestrings · August 02, 2016, 02:35:51 PM

Am I mistaken in the notion that using no load pots can produce the same effect as wiring straight to the jack??

- georgestrings

Dave W · August 02, 2016, 02:43:46 PM

A tone control is a passive treble bleed circuit. With the tone control on 10, there's no bleed of treble frequencies to ground, no matter whether you're using 250k, 500k or 1meg pots. They're all equally as bright as the pickup will allow.

The only way you can make it a bit brighter is by eliminating the pot entirely, which removes its resistance load from the circuit. As amptech said earlier, you can do that either by removing the pot and wiring direct, or you can buy one of those no-load tone pots which do the same thing when the pot is all the way up, while still allowing you to roll off treble when you turn down.

Quote from: georgestrings on August 02, 2016, 02:35:51 PM
Am I mistaken in the notion that using no load pots can produce the same effect as wiring straight to the jack??

- georgestrings

Yes.

georgestrings · August 02, 2016, 02:46:37 PM

Quote from: Dave W on August 02, 2016, 02:43:46 PM
A tone control is a passive treble bleed circuit. With the tone control on 10, there's no bleed of treble frequencies to ground, no matter whether you're using 250k, 500k or 1meg pots. They're all equally as bright as the pickup will allow.

The only way you can make it a bit brighter is by eliminating the pot entirely, which removes its resistance load from the circuit. As amptech said earlier, you can do that either by removing the pot and wiring direct, or you can buy one of those no-load tone pots which do the same thing when the pot is all the way up, while still allowing you to roll off treble when you turn down.

Yes.

You're definitely right about tone pots, but it's my understanding that higher value volume pots will have an effect on a pickup's treble output - although maybe I'm mistaken about that....

- georgestrings

Dave W · August 02, 2016, 03:13:00 PM

Quote from: georgestrings on August 02, 2016, 02:46:37 PM
You're definitely right about tone pots, but it's my understanding that higher value volume pots will have an effect on a pickup's treble output - although maybe I'm mistaken about that....

- georgestrings

In theory, a 500k pot will load the circuit a little more than a 1meg pot. In practice, you won't be able to tell the difference in a blind listening test with both on max. OTOH, you should be able to hear a noticeable difference with no load, although it won't be much.

Highlander · August 02, 2016, 03:54:02 PM

I have "straight through" as an option on my PC with each pup o/p on a different XLR pin... raw Mud and T'Bird...

amptech · August 03, 2016, 12:23:31 AM

Quote from: Dave W on August 02, 2016, 02:43:46 PM
A tone control is a passive treble bleed circuit. With the tone control on 10, there's no bleed of treble frequencies to ground, no matter whether you're using 250k, 500k or 1meg pots. They're all equally as bright as the pickup will allow.

..As bright as the pickup and tone pot will allow is more correct. Correct me if this is not the case with TB+ circuits, but with the tone pot on 10 you bleed the trebles through whatever resistance your pot value is to ground via the tone cap. Not that I'd ever bother changing the value to 1M, because as you said the pot will have more like an on/off function and have a lot of useless travel, but it answers georgestrings' question.