I'm curious as to why you want to replace the stock supply, and what you are trying to accomplish as a result. If I'm not mistaken, the Amazon uses an outboard speed controller. If so, then changing the wall-wart probably isn't going to make much of a difference either way (unless of course the original is dead) If you are having speed control issues with the deck, that's another can of worms entirely.
Custom Power Supply for 6v DC Motor
I'm trying to find a more substantial power supply to replace the wall wart that came with my Amazon Model Two. I need a 6v ac/dc converter. Anyone know a source for something like this? Or someone that could make me one? I can get a Black Lightening from Red Wine Audio but that's $1000 plus. I'd be willing to spend half that.