how do you pick what type of POTs you would need?

[TimmyGT]

so I'm working on fixing the P+J bass that I was given for free. I had to glue the body back together and so I had to remove everything off the body. when I did this I notice the wiring and soldering looks terrible so I just want to replace it with new parts. the bass has the P+J style pickups with the J pickup being a DiMarzio but Im missing the split pickups so I'm thinking about changing the bass to be active instead of passive. I have never built a guitar before so I need all the info I can get for picking out parts for this bass (POTs and maybe pickups if I go active).

 

[line6man]

http://www.talkbass.com/forum/showthread.php?t=494664
http://www.talkbass.com/forum/showthread.php?t=520484

In my book, it's strongly personal preference.

FWIW, I have changed my mind about linear versus audio considerably since posting in that thread.
I strongly suggest that you get linear taper volume pots, as they have a much smoother roll off, without that big jump from "10" to "8-ish" that you get with audio taper volumes.

Use an audio taper for the tone control though. Linears will have very little effect until the end of the rotation.

 

[TimmyGT]

what about active vs passive, would you use different pots?

 

[line6man]

what about active vs passive, would you use different pots?

The low impedance output from active pickups or a preamp works with 25K or 50K pots.

Depending on the preamp though, the volume could either be before or after the preamp, so if it's before the preamp's input with passive pickups, it would still be 250K or 500K.

 

[TimmyGT]

is there a difference between the pots I would use for my volume vs tone? or can I just buy 3 of the same pots and see how I like it?

 

[bassbenj]

what about active vs passive, would you use different pots?

You have to say what you mean. There are different ways to go active.

But first let's start passive. With passive tone and volume pots are usually either 250k or 500k and are either audio or linear taper. The advantage of passive is that there is nothing to add noise (hiss) or muddy the tone. Everything feeds direct. Also there are no batteries to go dead. Generally speaking most bass players think a passive tone has a little "something" that active basses don't. Minor difference, mind you, but there.

The disadvantage of a passive bass especially a P/j or such is that knobs tend to interact. The volumes change the tone. The tone acts differently at various volume settings etc. Plus all you end up with is a "toy" EQ control. Thus, for any serious EQ you end up fooling with your amp controls or if playing through a DI just toughing out not having any controls. So in this case an active bass is better.

Active comes in two types. The standard thing you find is a preamp and tone circuit essentially added between the standard passive circuit and the bass jack. Since the controls are ahead of the active circuit they are identical to the passive case. The active preamp circuit gives you some amplification and EQ in two or three bands.

The other is the active pickup. EMG makes these for example. In this case the amplifier is build right into the pickups. These kind of pickups don't use the standard passive circuits and usually take 25k or 50k volume pots. They mix well without interactions. If you go this way simply follow the manufacturer's wiring diagrams.

Personally I like the standard active arrangement since it's basically a passive circuit which lets you add a switch to bypass all the parts that run with a battery. That gives you emergency back up if the battery ends up dead and you don't have another.

And note that with a P/J arrangement, you'll want the J to be some kind of hum canceling pickup. The P is naturally a humbucker but the J is usually single coil which hums. I'd recommend Fender "noiseless" Js or other hum-canceling replacements. personally I don't like the tone of stacked coil Js though they are hum canceling.