passive control problems

[Kev]

right

i have a cheap westfield jazz bass which im modding up to be a decent bass (its got a good neck n weight so its worth it for me)

however

the volume controls seem screwed. im guessing it should just be volume, volume, tone?

the tone works fine, but the first volume knob does nothing until its completly counterclockwise, where it cuts the neck pickup, and the second volume know again does nothing until fully turned, and then cuts both pickups.

whats goin on here??

iv just fitted some lovely fender japan pickups to it, but the problem remains the same

wiring, or f***ed up pots??

[neepheid]

Check what kind of pots they are. Linear taper pots (often marked Bxxx, where xxx is the ohm rating of the pot, often 250 or 500 in passive basses) will do this. Make sure you have log or audio taper pots (marked Axxx, as above), they work in the way the human ear expects.

[Kev]

B500 is what they say, so this is normal?

[clauster]

For the vols you want A500

[clauster]

It also sounds like you've got your pots wired in series, so the front one controls the neck and the rear one acts as a master volume.

[BOD2]

The link below shows standard wiring for a 2-pickup volume, volume, tone Jazz bass.

[url="http://www.seymourduncan.com/support/wiring-diagrams/schematics.php?schematic=std_jazz_bass"]std jazz wiring[/url]

Copy the wiring from this. You can use 500K or 250K audio taper pots.

[Kev]

okay, so i change those volume pots to a500's, but it will be alrite to leave the tone pot as it is??

[clauster]

If it's working okay, yes.

The schematic Bod posted is the standard VVT wiring, so you may need to change the wiring of the vols if the middle pot cuts all sound and not just the bridge pup.

[Kev]

okay explain this

just picked her up n plugged in...

the volume pots are workin as they should

iv not opened her up or anything since checkin what the pot types are

wtf?

[Merton]

Dirty pots probably?

[BOD2]

A bad solder joint somewhere, or a stray strand of wire shorting something out ?

If you moved the wires to see the pot values or turned the pots slightly then this might have "fixed" the problem. Check all the solder joints for loose or "dry" connections (good solder joints are bright and shiny not dull/grey) and make sure there are no loose wire strands of any debris lying around.

You should try to fix this now otherwise it'll likely come back to plague you later !

[clauster]

+1