Installing selectable resistance switch for pickupss

[Ken B.]

I saw video on YouTube about installing a 250k/500k dual pot for selectable resistance on a guitar pickup for more tonal options. Then I saw this article on Seymour's website about making your own "dual pot".

https://www.seymourduncan.com/blog/tips-and-tricks/create-a-two-stage-potentiometer

OK, so...one question: why not use a 4 or 5 position slide switch, and install multiple different resistors for 250k, 333k, 500k, 750k, and 1000k settings?

Another question about this article, why does the author use a 500K pot, but then install a 510k resistor with the switch and say that this now gives him a 250k/500k switchable pot? Shouldn't he have used a 250k resistor?

 

[freefrog]

I saw video on YouTube about installing a 250k/500k dual pot for selectable resistance on a guitar pickup for more tonal options. Then I saw this article on Seymour's website about making your own "dual pot".

https://www.seymourduncan.com/blog/tips-and-tricks/create-a-two-stage-potentiometer

OK, so...one question: why not use a 4 or 5 position slide switch, and install multiple different resistors for 250k, 333k, 500k, 750k, and 1000k settings?

Another question about this article, why does the author use a 500K pot, but then install a 510k resistor with the switch and say that this now gives him a 250k/500k switchable pot? Shouldn't he have used a 250k resistor?

Hi,

1)Why not? Probably because lowering a typical tone pot already does what you evoke - the tone capacitor being really involved from 3.5 to 0/10 approximatively: from 10/10 to 3.5, a tone pot is mostly varying the resistive load ("mostly" being not synonymous of "only", of course: I'm not saying that a tone cap can't be heard at all but just that its presence or absence is not much noticeable during 2/3 of the curve on a tone control).

Illustration of what I mean below (it's about a bass guitar and it's a sim... but my archives are full of lab results like that: I've just not enough time to search and share 'em right now).

https://www.talkbass.com/attachments/jazzpu-jpg-jpg.2971673/

2) 500k in parallel with a 500k pot = a total load of 252,47k. And 250k in parallel with 500k = 166,66k. You can check it by using a calculator like the one shared below.

https://www.allaboutcircuits.com/tools/parallel-resistance-calculator/

FWIW.HTH.

 

[freefrog]

Can't edit my answer so I'll just add a footnote.

For a load of 1M, one can use a 1M volume pot and a no-load tone control.

Obtaining a load of 250k just requires to set the tone control aforementioned @ 333k : in parallel with the 1M volume, it will give an overall value of 249k. And @ 333k, the cap of the tone pot doesn't yet reshape the sound drastically...

Etc.

 

[Ken B.]

freefrog,

thanks for that info. I clicked the link. Was there a calculator?

Also, are the tone and volume pots supposed to match in resistance

 

[Ken B.]

freefrog, Click the 3 dots to edit posts.

 

[playas]

The forum has problems with editing posts with smileys/images and generally doesn't allow you to edit posts that have anything more than text.

 

[Mincer]

The forum has problems with editing posts with smileys/images and generally doesn't allow you to edit posts that have anything more than text.

It has been that way for awhile.

 

[freefrog]

Yeah, editing posts with links systematically gives an error message.

Below is the calculator evoked in my first reply. Sorry for the faulty link, I was tired.

https://www.allaboutcircuits.com/tools/parallel-resistance-calculator/

 

[Spaghetti Bolo]

freefrog,

Also, are the tone and volume pots supposed to match in resistance

No. The volume control is wired as a voltage divider, whilst the tone control is wired as a rheostat i.e. a variable series resistance between the capacitor and ground. A 250k vs 1Meg volume control of the same taper will still respond the same way (tonal effects aside). A 250k vs 1Meg tone control of the same taper will feel different in use; the range will be all bunched up with the 1Meg (which works for some).

 

[freefrog]

freefrog,

[...]

Also, are the tone and volume pots supposed to match in resistance

Spaghetti Bolo has already replied but politeness wants me to answer too.

No, volume and tone pots are not supposed to match: one can use whatever value from 100k to 1M for both (I've even mounted a 50k tone once by accident instead of a 500k. The tone was dull but still usable).

To add my two cents to what our fellow member shared in post 9: something to keep in mind is also that a 1M pot makes the sound brigther when full up but somehow darker when set half way (because the resistance in series with the pickup is higher). So a 1M volume pot might require a treble bleed cap.

FWIW