Fred...I'm building something very much like you describe. I had thought of using a 4-wire phone jack like you are using, but thought the wire gauge might be a little on the slender side...Have you had any issues with that..? Particularly on the 12v input side. How long of a cord are you using?
I like the idea of placing the Darlington on the aluminum base...!!! :thumb:
I didn't use a phone jack because I thought those were too frail in my ham-fisted plugging and unplugging. I used a 10ft coiled phone handset cord with the ends cut off. One end went inside the controller, and the other mated to an about 3/4" by 3/4" square 4 pole plug I think I got at Radio Shack. The plug prongs are about the size of 120 volt plug prongs. The prongs are oriented so that they only fit one way - a key feature for folks like me!
Something I might consider if I were building one again is to use a round 4+ pole trailer wiring plug set - with the handset cord. The flat trailer plugs are awkward to plug and unplug, but the round ones work nicely and are a reasonable size for handling. I love the coiled cord for avoiding trip hazards.
My current demands were very modest, and the broken AHM train set power pack I use for a power supply probably couldn't put out a full amp anyway. Wire size of the handset cord (22, 24, or 26 gauge, I can't remember) is probably marginally adequate, but didn't cause any problems with my MDC Climax (biggest current draw of my operational locomotives).
If I get to unpack some of my train stuff this weekend, I'll post a picture. I've spent the past few weekends preparing for winter and rebuilding all 3 of the family computers. But I need to unpack the trains, figure out what is excess (since we're going to be stuck in this house for a
loong time - at least until I don't have to pay to sell it! :cry
, and put it on eBay. At least I have an extra (very) small bedroom in the basement for my office, modeling shop, and layout.
hope this helps