Buzzing Bass

[ChaosGwar]

I just replaced the control pots in my P-bass. It still had the stock pots from when I bought it. The volume was broken so I figured I would replace both of them while I was at it. I got everything put back together, wired as per the Seymour Duncan wiring diagram. Now, when I plug it in, and turn the amp up, there is an awful buzzing noise. It gets worse when I touch any metal part. Strings, bridge, pots, p-ups, tuners, everything. I figured it is a ground problem, but all the wires are fine, grounded where they are supposed to be grounded. I don't get it.

I know it's not my amp because it doesn't buzz with my other bass.

And, there aren't any techs close, otherwise I would say screw it and take it to them.

[Rockin John]

Is the ground wire to the bridge still intact and making good connection?

John

[pkr2]

CW:

You might try using a piece of wire to temporarily ground each of the ground points in the control cavity to the ground lug on the input jack.

You dont have to solder the temporary wire in. Just put an alligator clip on the end of the temporary wire and clip it to the lug ground on the jack while touching the end of the wire to each ground point.

You should get a reduction in buzz (hum) when you get to the offending ground point.

If your ground circuit isn't star grounded, it should be. If the metal cover of the pots are not grounded with a wire soldered to the pot case, they should be.

Make sure the wire that grounds the cavity cover is making good connection to the cover when it's in place.

A multimeter, or even a battery operated continuity tester is a valuable tool when diagnosing this sort of problem. I wouldn't use the battery operated continuity tester if you have active electronics, just to be on the safe side.

I have learned the hard way that the first thing to do is to go over the work that has just been done with a fine tooth comb (figuratively speaking) before getting too far out in left field.

There is always the possibility that you have installed a bad new pot but it's highly unlilely. There is also the possibility that you have damaged one of the new pots by overheating it while soldering. Also highly unlikely but possible.

Let us know what you find.

Good luck, Pkr2

addendum: A link to the circuit schematic that you followed might help us to help you.

[ChaosGwar]

This is the wiring diagram that I followed.


The ground wire to the bridge is fine, that was the first thing I checked. The capacitor is soldered just like my old potand all the solder points match exactly. I'm guessing it is only one of the ground points that might not be connecting.

[pkr2]

Originally posted by ChaosGwar
This is the wiring diagram that I followed.


The ground wire to the bridge is fine, that was the first thing I checked. The capacitor is soldered just like my old potand all the solder points match exactly. I'm guessing it is only one of the ground points that might not be connecting.

CG:

If the volume control works normally and you have any output from the pups when you pluck a string, about the only ground left is the ground at the jack.

Look closely both at the jack and the connection to ground.

You should be able to locate the bad ground very quickly using the temporary jumper wire. Just be sure that the temporary wire is making a good ground.

It is very unlikely that the problem has anything to do with the tone circuit.