Low output Jazz or...?

Hello Bass friends,
Recently I "upgraded" my Squier VM Jazz bass with a pair of fender MIM player pickups. The stock pickups wasn't Jazzy enough (almost no burp) and their output was very very low comparing to my Yamaha BB424X. I shielded the bass first and then I installed the pickups. The result is disappointing because the output is now even lower and tone is almost the same (in youtube videos it was very close to my liking).
I adjusted the pickup height to increase the output but it made just a little improvement.
For getting a normal output I have to crank the master volume on my Zoom B1xon but there is an annoying hum now.
I don't know what to do now, is this normal for Jazz basses?
Is it because of bad strings?
Did i do a bad wiring?
I'm desperate. Last night I was thinking about selling the whole thing...
Any help and advice will be appreciated.
This is the wiring pic. I connected all ground wires ( bridge, bridge cavity shield, bridge pu and neck pu) to a terminal and made it only one wire out and then I soldered it to the shielding. I checked the continuity and it's fine)

 

Yes hum is present always but I think with that much of gain probably any bass or setup has a hum. It decreases a little when I blend both pickups at full volume.
My main compliant is the low output which makes me to increase the gain.
My rig is so simple. Bass to Zoom and headphones out. There is No amp or speakers or any pedals in between.
I have another Squier but that has a big Humbucker pu with active electronics and its output is fine.
Even my Yamaha BB on bridge pu soloed has way more output than Jazz bass. Master vol on Zoom is set to 35 with two other basses but with the Jazz it's at max 120(+hum).