I should probably be more specific about what I'm doing here... I'm making a homemade version of a "Chassis Ear," which basically is a listening device used to pinpoint where noises are coming from (typically on a car while you're driving). What you do with this thing is you place a couple of clamps (each of which contain a mic) in the area you think the noise is coming from. You then drive the car down the road and, with headphones on, change each channel on the tool and listen in to hone in on where the noise is loudest. While you're doing this, you can also enjoy all the stares you get from passersby as they see all these wires hanging outside your vehicle
What I did is used a device called "
Listen Up" (actually, it's a clone of one I got from Harbor Freight tool store), disconnected the internal mic and extended the leads to connect to a 2-pole, 4-position switch. On the other side of the switch, I have 2 wires for each of the 4 positions (which would be a total of 8) traveling to 4 of those mics, each of which is secured to an alligator clamp. I tried the keeping polarity correct throughout the wiring, though I did have to assume the red and black colored wires coming from the "Listen Up" meant positive and negative, respectively. I hope that all makes sense.
So as far as pre-amps, I really don't know if the "Listen Up" contains a preamp, though I imagine it does to get the amplification as high as it does go. I get the feeling, tho, from what ya'll are saying is that I definitely need to go with something that's at least shielded.
Many thanks for the continued help.