Those MRAs had to be the most impressive amps ever put out. Huge but awesome. Personally don't care about class D although they are better than class A or A/B for guys with bad backs.
Big Krells Have Vanished From The Used Market
Once upon a time several years ago, you could always find several of the big Krells for sale on Audiogon. I'm talking the 500-750 wpc big irons. Now since Krell no longer makes anything bigger than 500 wpc, anyone with the 600, 700, 900 wpc amps are holding on to them because there's nothing new by Krell to replace them with.