Which pots for a stack-knob dual P-pickup bass?

knuppe · #1 02-10-2010, 08:36 AM

I have a question...

I need some pots for my new bass. It´s a p-bass with a P/P pickup-configuration, made by Dan Atkinson. I want to install two stack-knobs with seperate volume and tone for each pickup. But I don´t know what types of pots to get... I have heard that 250K should be right. But some come with 250K and 500K, and quite frankly I don´t anything about this. What´s the difference between 250K and 500K? Is there a difference between precision-pots and jazz-pots? Any thoughts on this? Let me know if you don´t understand what I´m asking. I´m Norwegian, so my english might be slightly off...

Thanks!

mellowgerman · #2 02-10-2010, 08:38 AM

I would recommend 250k for a p bass. The 500k will give you a slightly brighter sound.

**line6man** · #3 02-10-2010, 08:53 AM

If you are going to have two volumes and two tones, you would want 500Ks to give you what would be closer to the traditional P bass vibe.

I wouldn't recommend having two tone controls though, they are going to interact.

Here are two threads on pot values:

What effect does 1 meg pot have? Also, audio vs. linear
Passive basses and the volume control, an explanation (science warning)

knuppe · #4 02-10-2010, 11:34 AM

One more question: When you say that 500K will give a brighter tone, do you mean when that pot is controlling the tone knob or the volume knob? Because I have found an alternative, this one: http://cgi.ebay.com/Fender-CTS-Jazz-...item48392c19f8

Will that one work? Does it matter that it says that it is a jazz bass pot? That one has 500K for the volume, and 250K for the tone...

Thank you for the replies so far!!

**line6man** · #5 02-10-2010, 12:32 PM

Quote:

Originally Posted by knuppe

One more question: When you say that 500K will give a brighter tone, do you mean when that pot is controlling the tone knob or the volume knob? Because I have found an alternative, this one: http://cgi.ebay.com/Fender-CTS-Jazz-...item48392c19f8

Will that one work? Does it matter that it says that it is a jazz bass pot? That one has 500K for the volume, and 250K for the tone...

Thank you for the replies so far!!

500K is brighter for both volume and tone.

For volume, there is a greater resistance between the signal and ground, so there is less high end loss.
For tone, there is a greater resistance between the signal and the capacitor, so the capacitor is not able to cut as much of the signal.

It doesn't matter if they call it a "jazz bass pot". There is really no such thing, that's just a term they use because it's commonly used on Jazz basses, but it can be used for any electronic application requiring that specification.

akmusicfreak · #6 02-10-2010, 08:45 PM

Line6Man.
Just a personal preference question.

Would you think it would be better to go with 2 500k pots and let the top end come threw and just use the amp's filter to take out what you didn't want ?

Or go with your 250k pots and have the bass's pots filter out what you didn't want ?

screaminglucy · #7 02-10-2010, 08:52 PM

250k has a nicer rolloff. 500k will seem like it's on or off

**line6man** · #8 02-10-2010, 09:00 PM

Quote:

Originally Posted by akmusicfreak

Line6Man.
Just a personal preference question.

Would you think it would be better to go with 2 500k pots and let the top end come threw and just use the amp's filter to take out what you didn't want ?

Or go with your 250k pots and have the bass's pots filter out what you didn't want ?

Well, if your asking my personal view on the matter, I've always felt it better to have the purest signal possible without the pots removing all the high end, because it's much easier to EQ out what you don't want than to try to EQ in what isn't there.

If you are going to have two 500K volume pots, that's going to be the same as one 250K pot anyways, assuming the pot is all the way up.
Of course, rolling either volume down is going to mess with the taper a bit, but it should be similar enough to having one 250K for all practical purposes.

**line6man** · #9 02-10-2010, 09:02 PM

Quote:

Originally Posted by screaminglucy

250k has a nicer rolloff. 500k will seem like it's on or off

Nonsense.

Maybe a 1M pot would have that effect, but 500K is a very common value in a bass.

I use 500K pots on my instruments, and they have a nice smooth roll off from 10 to 0 without any jumps.

Perhaps you were using an audio taper pot with a poorly spec'd taper?
Try a linear taper and that should solve the issue of the pot functioning as an on/off switch.

screaminglucy · #10 02-15-2010, 09:51 PM

Quote:

Originally Posted by line6man

Nonsense.

Maybe a 1M pot would have that effect, but 500K is a very common value in a bass.

I use 500K pots on my instruments, and they have a nice smooth roll off from 10 to 0 without any jumps.

Perhaps you were using an audio taper pot with a poorly spec'd taper?
Try a linear taper and that should solve the issue of the pot functioning as an on/off switch.

if it's just a master volume i agree...but if it's V/V and you are blending the pickups 500k always makes it seem like on/off and it's hard to get any kind of blended sound (at least to me).