I did use the search: Worth it to change gauge?
 

Currently, my Jazz bass has D'Addario nickel round wounds in "light" gauge. (0.045-.100) The feel is good, but I wonder if a change is worth it.

My gauge of strings on my electric has crept up (I'm now using Ernie Ball Power Slinkies (0.011-0.048) on my Les Paul. On acoustics, I try to stick with what the manufacturer puts on it.

Bass... Does string gauge make as much difference in the sound as it does with guitar? My bass has EMG-JX pickups. I'm looking for a fatter sound. (Yes, I know that it'll still be a jazz bass no matter what. :D)

I know a lot of basses come with 0.050-0.105s, and my local dealer has some Ernie Ball Power slinkies with the E string at 0.110.

I'm also thinking about a bone nut and a high-mass bridge.

So, what would you do if you were contemplating changing something for a better sound?

Yes. Gauge does make a difference but not as much as you might think unless you make a drastic change.

What do you mean by FATTER sound?

Thinner strings will give you slightly less highs and slightly less sustain, but you might not even notice.

The example of what I'm really looking for in bass tone would be John McVie in this video:

http://www.youtube.com/watch?v=vxIACAU9uJU

I don't know who the bass player is here, but this is also what I'd call great tone. Joe Bonamassa "Takin' The Hit."

http://www.youtube.com/watch?v=M1kjD0Q210c

I know that a Jazz bass will always be a jazz bass with a jazz bass tone, and I'm good with this. I just want as good of a sound as I can get. :D

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I think McVie is using flatwounds. He seems to be palm-muting at the beginning of the song. Sort of gets a bit buried from there, I can't hear him clearly.
(My hearing has been damaged by years in heavy industry mind you.)

The other guy sounds like he's using flats to me too, along with maybe a flange effect.

So, in summary, maybe consider a set of heavier gauge, non-bright flats (eg. forget Chromes!) and turn your tone down a little. I'd be finger-plucking between the pickups on your Jazz with both volume controls wide open.

There are guys on here who are infinately better at analysing bass sounds than me. Hopefully a few will chime in without flaming me! :D

The first thing to try is lowering your pickups - because it's free! You'll lose a little volume and brightness, but you have an amp to compensate for the volume. If your nut is cut for the gauge you have on, I would try a flat wound in that same gauge. If your nut can take a heavier gauge, try that. I would sort out the strings before moving onto a new bridge. I wouldn't bother changing the nut at all.