Krell KSA100 vs Threshold 400A vs McCormack DNA 0.5

@legarem: That Son of Ampzilla for $460 is an excellent choice! I own two of them! And I bought one brand new in 1977 - and stupidly sold it! Still a contender for "best sound per dollar"!

@legarem I'm wondering why you didn't follow the advice given to you in this thread.  I specifically told you in my reply...

"Just to be clear though with my recommendation. (Mccormack) is a "no-brainer" assuming you are getting it modded. As good as it was in stock form, the McCormack is past it's useful life and all the driver boards need to be replaced at this stage of it's life cycle. If you are looking at those 3 options for use in used stock form, I say the "no brainer" answer is to buy NONE of them. Get a much more current used amp or something new from quality budget suppliers like Emotiva, Parasound, etc."

I'm not sure why you would ignore that specific advice, but don't make the same mistake again.  There's no point in buying an old used amp at a super cheap price to milk in it's stock form for whatever useful life is left. 

As I said before, either get your McCormack modified or buy a brand new Emotiva that fits your budget.  Their newest generation amps are excellent and steals at the price. The modular construction and direct sales allows them to sell for far less than they would otherwise.  I have a couple of them myself (as well as ARC, McIntosh, McCormack and others), so I'm not just making this stuff up. You get a full warranty and tons of power that will work with any speaker.

I finally bought a pair of Monarchy SM70 class A amps. Presently I use them in bridged mode (70W) with my Morisson speakers. What a surprise ! Relax effortless sound, huge soundstage. I simply love what I hear. As they are pure class A, they heat a lot but in my basement this is a good thing even in summer. The McCormack will be repaired this winter but i’m really not sure it could dethrone the Monarchy amps.

@legarem I have owned SM70s, and they were quite a bit better when driven balanced. Quite a night and day difference, actually. Enjoy ! MrD.

But I think you can't use balanced input when you use them in bridged mode.