Shielded Cable?

I tried shielded cable for Jazz bass wiring years ago for some pretty lame 70's pickups and as I recall there wasn't much difference in noise reduction

 

The connections inside a bass are short. When they say "long," they mean much longer.

Pups usually come with shielded cable, but if they don't, you should just use their wire as-is.

You don't need to use shielded cable anywhere else in the control cavity. Doing so may be more susceptible to ground-loop problems. For hum, make sure you shield the cavity and pup routs with metal foil or paint.

And, if you have single-coil pups, they may still hum. They'll pick up hum from their tops anyway.

 

FWIW, when using a cable that has a woven external surface layer of copper or aluminium with drain wire, only connect one end to a "earthy" point ( single point is a good technique. Current cannot flow through a single "earth" point ie if you use both ends of the shield as an earth connection then current can or will flow and you will have voltage gradients along the shield conductor.

Another valid technique is to twist two or more wires together to make a semi shield for the active conductor. Inter wire capacitance increases though at our bass frequencies this is not so much of an issue i believe. For the pedantic you could use RF style teflon shielded cable like RG174 a teflon cable that will not short out from overheating with soldering temepratures. Hard to strip however and cuts easly if abused. The good quality brands are silver plated copper both active and shield conductors. BTW silver is the best conductor then gold not often quoted.

Kind of wonder about full shielding of control cavities, though done properly it is a all encompasing technique. Though mutual coupling in earth situations is not often understood ie high impedence circuits with induced voltages/currents from external fields is not always reduced by "shielding" most times it just increases the coupling and noise problems, both common mode and normal mode. Bit technical i know, just the way it works out in practice.

Regards, John.

 

For inside an instrument, shielded cables are just not gonna produce the results you are hoping for...sorry. Shielding the entire routed cavity will overall, will give ya better reduction in that 60-cycle hum that we all hate. Also, good solid solder connections on switches and pots will also be quite helpful.

 

And nothing will stop hum pickup through the top of the pickups. If they're single-coil pups, you must run them at the same volume. Even then, they may not be silent.

 

On my Vintage Vibe Jazz Bass pickups (http://www.vintagevibeguitars.com), the pickup itself is shielded with copper foil after being wax potted. The wire used consists of a hot and a cold shielded with braided shield. The shield is tied to the copper foil. That technique works great. These are the most quiet single coils I've ever used.

the Jag is known for it's noisy electronics. My guess is that you have multiple issues to deal with. Shielding the pickups and leads might be the least of them...

 

One idea that might be a bit of a compromise if fooling around with rather sharp copper foil sounds 'not so good': Stacked single coils. DiMarzio makes some good "noiseless" pickups for guys that still want to capture that single coil vibe without the constant irritation of battling 60-cycle hum. That is just one option among many good ones already posted on this thread.

 

The electroic's in the Jag are thought to be pretty noisy. If you really want quiet , gut the electronics... then see if that is quiet enough. if not, quieter pickups might be the next step.

Note - I wouldn't recommend attempting the retrofit of copper foil shielding on a pickup. I buy 'em done that way to begin with.

Note 2 - I'll admit that I haven't been following Dimarzio for a bit however in general there is no such thing as a stacked single coil. What Dimarzio used to sell was a humbucker in a stacked format. Quiet yes but it doesn't sound much like a single coil. Being a J Bass fan, I wasn't real happy when I tried them as they didn't have the 'edge' of a good single coil. they were quiet but lifeless. YMMV and all that...