Objective is to install a passive magnetic pickup, passive volume &
tone pots, and another 1/4" jack - an entire signal path independent of
the stock electronics - in a Line6 Variax 705 five-string bass.
Here's a big picture of a Line6 Variax 5-string:

A picture of the jack (stock electronics) - sorry this picture is of a
4-string version; mine is actually a 5er like above.

Okay, here's what I want to do: Install a single passive magnetic
pickup, with an independent set of controls (passive volume &
passive treble cut), and an independent 1/4" output.

I have a Seymour Duncan SSB-5b Phase II bridge-sized passive pickup and
a pre-wired Jazz Bass control assembly (passive V + V + T + 1/4" jack).
Here is more info about the pickup:
http://www.seymourduncan.com/products/bassesdescr.shtml#PassiveBassSoapbar
This install might be tricky, because directly behind the "sweet spot"
is the cavity for the 6x AA batteries, and a channel where all the
wiring from the piezo bridge runs to the control cavity:


The battery clip, which holds the six AAs, is shown outside the
cavity. Underneath, you can see the channel with the 6 individual
wires from the piezo saddles headed to the control cavity on the front
of the bass.

This is the front of the bass, with the pickguard lifted. As you
can see, under the pickguard, there is a large shielded box which holds
the Variax electronics. This doesn't leave a lot of room for
additional pots.
Please let me know what you might be able to do.
My contact info:
Dave Muscato
Mailing address:
614 Business Loop 70 West
Columbia, MO 65203
Cell phone: (573) 424-0420
Email: mail@davemuscato.com
Thanks,
Dave