Stacking pass labs power units??

True.  I will try it, but wanted other thoughts and will see what pass says.

Will you be running both preamps at the same time?

If not, then I see no problem.

B

The folks at Pass said it was no problem to stack the power supply chassis together and then separately stack the two preamps. So I did this, but found that the two preamps stacked together produces more heat than I'm comfortable with. (not that they were too hot to touch, so I'm not suggesting there was overheating going on, but they were in a middle shelf of a rack and therefore, even though they were "breathing" there was still a roof over their head and warmer than my liking) So they are stacked back on their respective power supplies. I just don't have any extra space to put four separate chassis. Pass gear is designed to stay on all the time and therefore they would be running at the same time.