pickup for bridge position?

ge86 · Post by **ge86** » Thu Apr 14, 2011 8:57 pm

Hi all, I'm new here and still relatively new to the wide world of fretless basses too...

Got a bit of a question about bridge position pickups.

My fretless bass was a home made one by a friends uncle, so I somehow ended up getting it free, which is awesome, but it also has a few flaws, the most annoying of these being the bridge pickup.

It has a jazz bass configuration with 2 single coil pickups, each with a volume control and a master tone control.

When I play with both pickups on, the sound is a little muddy, but I dont get any noise.

With just the bridge pickup on, I get the classic Jaco kind of sound, but I also get a lot of hum and random EMI noise.

The pickups on it are cheap no name ones, so I'm not sure if replacing them with a decent set of single coils might fix the problem of both the muddiness and the noise?

Alternatively, how would a p-bass pickup sound in the bridge position? I've never seen it done like that but not really sure why...

Another alternative I'm not sure about is the hum-cancelling single coil models offered by both Dimarzio and Bartolini (the DP123 and 9J1 respectively). Are these actually single coils or are they humbuckers made to look like single coils? And how do they differ in sound from regular single coils?

FretLessSince68 · Post by **FretLessSince68** » Fri Apr 15, 2011 2:29 am

You might try improving the shielding in the P/U routes and control cavity.

The noise you mention is classic Fender Jazz single coil hum. Better shielding is a good place to start and won't cost you much. DIY- get some adhesive back foil from Stewart-MacDonald or other source. http://www.stewmac.com/Shopping;jsessio ... yword=foil Be sure the foil is all grounded properly.

I believe the replacement P/Us you mentioned are indeed dual coil humbuckers in a case with the same dimensions as a Fender Jazz. I think these sound fine although I can't quantify the differences. Go to the Seymour Duncan site tone chart and listen to their clips of various pick-ups. http://www.seymourduncan.com/

Installing a Precision type P/U in the bridge position has been done but I don't see where much advantage would be gained over a better quality Jazz P/U. The routing alone should be a strong disincentive to do this. Personally, I think a replacement Jazz humbucker is a better idea if you are unhappy with the existing P/Us.

If you do get new P/Us, make sure that the width is equal to your existing set, they do vary.

Try improved shielding first, even if you end up replacing the P/U, you will benefit from better shielding in either case.

Hope this helps, and welcome to FretlessBass.com

ge86 · Post by **ge86** » Sun Apr 17, 2011 6:56 pm

Ok will try the shielding, I'll let you know how it goes.
Thanks

FretLessSince68 · Post by **FretLessSince68** » Sat Apr 23, 2011 5:29 pm

Ideally, the P/U leads should be two wires in a braided shield with the shielding properly grounded on one end only. If they are not shielded then it will usually be a pair of wires. For best EMI rejection it is important that this wire pair be twisted, as in "twisted pair".

You can replace the unshielded pair if you know how to solder. Just acquire some decent quality small shielded wire (2 wires inside shield) and go for it. Be careful when soldering to the P/Us as they don't like excessive heat and are difficult to repair if damaged. On the heat sensitive P/U terminals, get the work done as quickly as possible. Use alligator clips as heat soaks.

Be sure to observe the only one side connected to ground convention on the shield to prevent ground loops.

Search the Internet for "ground loop" for more info on this subject.

Don't forget to shield the inside of your control cavity cover.