450 w 12 v server power supply connected to 25 amp ESC. With this arrangement, I get a very compact 1/2 HP variable speed motor for $100 or so. The parts are all pretty high quality too-
I made the aluminum enclosure from .062" aluminum found in the remnants bin at local metal supplier. The top handle and aluminum for knob came from a dumpster, and the pushbutton switch on the top was recycled from my wooden computer case build.
Servo tester with 'mode' switch and potentiometer breakout.