Thanks - good to hear another vote for diycnc.

A 'proper' PSU might be an idea as you say but I think I'll have a go with the free computer ones first. If they do fail, I'm hoping any failure mode would just result in lack of power, not frying all the stuff they're connected to...:cry:

That system you ordered looks very much like what I was thinking. Odd that his 'standard system' with the 5A driver cards uses the 24V supply - higher is better within reason as I understand it. Maybe it's to avoid needing the 'high voltage' option on the PBB20.