I've got the Wolfgang TB-350 spindle for my PCB mill, with the DC motor (I'm about to move over to the UK, so the 110VAC version didn't seem as wise). Honestly, it works pretty well connected to a spare PC PSU that I have, but... okay, I haven't measured it (not sure how), but it doesn't SOUND like it's very high speed.
I went to my local electronics surplus store, but a PSU rated at around 12V and "up to 12A" (according to the Wolfgang site) was pretty spendy. I've read discussions on boards and some folks recommended a linear power supply vs switching (I confess I've tried to read up on it and am not sure what the advantage would be). The Wolfgang site said the motor could even be run "off a car battery"--sounds a bit dodgy, but possible.
So I guess my question is this: for PCB milling, should I stick with my switching PSU, try the car battery, or just hold out and find myself a linear DC power supply with the "right" ratings? Also, is there a good way to control the speed? My gecko G540 has VFD out, but I'm guessing that's not so great for DC motors...