I have a Fender Aerodyne P-Bass Special ...
I replaced the bridge PU by a DiMazio Humbucker - and the brigde PU still has no chance against the P pickup. Even with paperboard under the foam to get it higher ...
I think it's the destiny of a PJ?
The Kramer is no problem with its J PU. But this is already a DiMazio??? The Yamaha surely would have to be custom rewound.
Is it only the loudness differnce and not the sound?
Would the bridge be okay if you raise the Gain of your amp?
In my wiring compendium is a solution. You can throttle down the output of the neck pickup by putting in a trim-pot. If you want to keep the full high tones, add a capacitor (like in my drawing).
Thwart the neck PU until it fits to the bridge PU and increase the Gain of the amp ...
The drawing is 2.6.03 (page 196 at the moment):
http://161589.homepagemodules.de/t29...-E-Baesse.html
(5.6 MB PDF at the end of the page)
If you don't want to thwart the neck PU you have rewire or find hotter bridge PUs ...