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[...] I was also looking at this one: http://cgi.ebay.ca/0-30V-0-5Ampere-DC-Adjustable-accurate-Power-Supply-/160456228081?pt=LH_DefaultDomain_2 but I couldn't find much info on it, which raises some flags.
So I think I'm down to two different supply options. One is a BK Precision switching supply (1-36V, 0-3A), the other is a Tenma supply at the same rating and form factor. The BK is $140, the Tenma is $200. The BK has a strange clicky control where as the Tenma has rotary dials. I like the look the Tenma better, but does that warrant an extra $60? Which would you folks go for? Here's the links:
I'll take you advice and build a cheap supply using an LM317
Hmmm, well I suppose I could get by with the LM317 if I strap on a nice heat sink, maybe. Let's say I drop 20V at 1.5A, which is 30W. Without a heat sink the T-220 package has a thermal resistance of 50°C/W (yuck), so the heat sink dissipating 30W will have a temperature difference of 50×30 = 1500°C, so the temperature will rise to 25+1500 = 1525°C (clearly above the 125°C thermal cutoff). However if I use a 3°C/W heat sink ($6 @ digikey), the temperature difference will be 3×30 = 90°C, so the temperature will rise to 25+90 = 115°C, which is close to (but below) the cutoff temperature of 125°C. So it is possible to get by with the LM317, but I'll need a really nice heat sink.
I'll also look into the transistor option as well. Do you have a circuit diagram? What about this circuit: http://electronics-lab.com/projects/power/004/index.html
Edit: Oh wow, check out this heat sink: http://canada.newark.com/h-s-marston/890sp-01500-a-100/heat-sink-extrusion/dp/15J9645 0.08C/W thermal resistance! I can pump through 1500W through this beast!