I think one at a time is your only option. You could try removing one at a time instead, but it may not help find the outlier your looking for. It felt a little silly to limit my case because of a power supply so I ended up with Trogotronic power. Its not a fancy linear system or anything, but it sounds better and can power a system with tube modules. I think the less % of total draw your system is for its power supply the better.