MIMF

I'm building a build to order Guitar, and the person specified a L.R.Baggs T-Bridge, and he wants it paired with an Equalizer Preamp.
I'm wondering about joining all 6 leads to a single micro plug that will jack into the preamp. I don't have a soldering iron small enough to use the circuit board that was provided, it appears simple enough to just strip the wire ends, solder all the outside sheathing to a negative wire, and all the cores to a positive wire, wrap the positive bundle in shielding material, and then proceed to the micro plug. I've done similar things with rod piezos, and I'm thinking since the 6 bridges are piezo transducers that this should work. I just need to keep the negative wire sheathing isolated from the positive solder cluster. I'm I wrong?

No, you're not, but it can be a problem working with that stuff. It's small, fiddly, and the wires often are difficult to work with and you might make a mess. I am not so sure of what circuit board that you mention, but I suggest just getting a small soldering iron. They are not expensive, and a good investment that you'll need sooner or later. Also, you can use the Harbor Frieght Router Speed Control to regulate the heat on a soldering iron, they work well for that.

The Ghost system has a board that electrically adds the six signals into one. This would be better than just soldering them together, IMO. Perhaps you can adapt the connectors, or talk the customer into a Ghost system.

The Ghost system looks promising for next time, but I already have the T-Bridge here. I'm just being a bit timid about jumping into wiring a $170 part for the first time.

G.S.

The last few times I've had to do this I just made a little circuit board with 2 long, parallel pads. I soldered all the shields side by side on one side and then did the same for the inner conductors.
You do need to be careful when soldering the shields not to crush them and short out the inner layer of insulation with the hot iron. I did that once and it took me a long time to find the short.

I have to agree with Mark that it's high time for you to purchase a small soldering iron. If you don't have a lot of room for a bench unit I'd recommend one of the fixed temperature tip units from Weller. I'm really impressed with how well they work. Get one with a small 700º tip, 35W element and no base station to worry about.