Mixing pots and capacitors

[Swills]

I’m looking at replacing the pots and wiring in a P bass that I’ve just bought from another chatter. 
 

I was about to click the BIN button on a pre-wired harness but then thought I should check my box of spares. 
 

low and behold I’ve got everything I “might” need CTS pots, fresh wires, brand new cap, switch craft Jack… sounds great, except for the values…

 

There’s a 250k for the volume, 500k for the tone and a 0.068uf cap. 
 

has anyone had any experience of wiring a P bass in this configuration? Is it worth a punt or should I stop being so tight and get myself another 250k pot 🤣

Edited November 27, 2023 by Swills

[Paddy Morris]

Definitely do it yourself. It's easy, and you'll most likely do s better job than whoever made the harness.

[neepheid]

9 hours ago, Paddy Morris said:

Definitely do it yourself. It's easy, and you'll most likely do s better job than whoever made the harness.

 

LOL, @KiOgon

[ahpook]

On 27/11/2023 at 22:02, Swills said:

I’m looking at replacing the pots and wiring in a P bass that I’ve just bought from another chatter. 
 

I was about to click the BIN button on a pre-wired harness but then thought I should check my box of spares. 
 

low and behold I’ve got everything I “might” need CTS pots, fresh wires, brand new cap, switch craft Jack… sounds great, except for the values…

 

There’s a 250k for the volume, 500k for the tone and a 0.068uf cap. 
 

has anyone had any experience of wiring a P bass in this configuration? Is it worth a punt or should I stop being so tight and get myself another 250k pot 🤣

 

Try it, it's no great shakes to get a 250k pot and switch later if you don't like it.

 

Experiment !

 

 

[MartinB]

I've got one like this and it sounds good to me. With tone all the way up, less of the high frequencies will be sent to ground compared to a 250k pot, so it'll sound brighter. Turn it down halfway and it'll sound the same as a fully-open 250k tone control. The capacitor doesn't do anything interesting until you roll the tone down below ~20%, at which point you start to get a small bump in the low mids. Compared to a standard 47nF cap, a 68nF will create a smaller peak and it'll be at a lower frequency - like 200Hz rather than 350Hz. It'll also roll off more of the high frequencies at this point.
 

[KiOgon]

4 hours ago, MartinB said:

I've got one like this and it sounds good to me. With tone all the way up, less of the high frequencies will be sent to ground compared to a 250k pot, so it'll sound brighter. Turn it down halfway and it'll sound the same as a fully-open 250k tone control. The capacitor doesn't do anything interesting until you roll the tone down below ~20%, at which point you start to get a small bump in the low mids. Compared to a standard 47nF cap, a 68nF will create a smaller peak and it'll be at a lower frequency - like 200Hz rather than 350Hz. It'll also roll off more of the high frequencies at this point.
 

He's about right you know 😉 said it all really 👍

[neepheid]

I was imagining the statement that someone with no track record would make a better job of it than a maker of harnesses if you had made the harness in question @KiOgon, as purveyor of the finest harnesses on BC, and it made me chuckle.  I think I expressed it a bit too tersely, and now I've probably overexplained it.  Humour is hard sometimes.

 

As you were, everyone...

Edited November 29, 2023 by neepheid

[Remus]

Use the 250k for volume and the 500k for tone.  You won’t notice a huge difference with the 0.068uf cap from a 0.047uf cap until you get to the last 1/8 turn or so of the tone pot.

[sandy_r]

For anyone in a similar situation (only have a potentiometer which is a higher value than required) but who has a fixed resistor of a similar value, you can approximate the actual required resistance curve by connecting the fixed resistor in parallel with the appropriate 2 lugs of the pot.

 

 

With a 470k ohm fixed resistor connected across these 2 lugs, a 500k pot. will give a good approximation of a 250k pot., with a max. variance of approx 15% around halfway:

(where 'R' = 470k ohm)

 

A similar method can be used to approximate an audio taper using a linear potentiometer

 

Edited December 1, 2023 by sandy_r