Custom Bass Upgrade and Mods

I'll consider this to be a "custom" four-string electric bass, 'nuff said. It features a solid wood body, natural satin finish, tilt-back 2+2 headstock, rosewood fretboard, jumbo frets, maple bolt-on neck, twin humbuckers, monorail-style bridge, passive electronics; and zero shielding. The control configuration is two volumes and two tones, and the output jack is of the barrel variety; buried in an angled recess on the front of the body.

So, what's not to love about this bass? Lots, according to the owner. The "electronics suck," said he. There was no master volume to turn down during breaks -- he'd have to turn both volumes down, and in the process; lose pickup balance when he came onstage again. He was also apprehensive about using it live because of inconsistent signal strength and various annoyingly-audible snaps, crackles and pops. That, plus a setup that wasn't comfortable for slapping and popping (his favored style). I told him I'd have a look and get back to him ASAP.

What I discovered made me a very unhappy man. The routing and woodwork was generally slipshod and rough, pots were of the 3-bucks-apiece variety; and the wiring iffy. Next, I tried to remove the barrel jack in order to check it; but there was no way to do so. There was no access route, no nut; no nothing. I had to dig a hole through the control cavity wall to get to it and push it out from the inside. When it finally came out, totally mangled and unusable; I had a Eureka moment. The builder had simply drilled a hole from the front of the body and shoved the jack in, with just a piece of strategically-wrapped paper to keep it in place! 

With this new-found knowledge, we had a no-holds-barred discussion and decided to retain the pickups, upgrade the electronics, shield the cavities and back plate; and change the control configuration to pickup blend, master volume, and master tone. I'd also be plugging the existing output jack recess and one pot hole, and drilling a new hole in the side for a new barrel jack; amongst other woodwork-related tasks. 

That being taken care of, it was time to address the setup issue. Thank goodness the truss rod was working as it should, and tightening it up little by little over the course of a few days allowed for less relief and lower action. I strung her up with Ernie Ball Regular Slinkys (50-105), set up the monorail-style bridge (a real PITA) and called the owner to take her for a spin. He was happy about the positive changes in his best girl, slapping and popping to his heart's delight; but nowhere as happy or relieved as I was :)