What pre/power amp for jm lab Mezzo's

Own a pair of jmlabs Mezzo running a Krell intergrated amp 400xi, just wondering what other people are using with what results, would like to move up to class A,any sugestion, I like Krell or Mark Levinson thanks for any feed back.
Ok, not really up to date with tube design I have read that tube can lack bottom end slam, is it better to go for hybrid design, what the best brands for money (second hand)do you use tube pre with these, I am open to experiment, what your thoughts
I feel hybrids are the way to go. They achieve a natural balance and sound, along with great slam. I use Kora Aries monoblocks with my JM Labs and the synergy is like I have never heard before. Simply fantastic amplifiers. But they aren't common and don't get the press they deserve (at least in the USA).
I owned 3 JM labs including the Mezzos, always found solid state amps to be too harsh on the titanium tweeter, especially the Krell 400xi. Try the Mcintosh MA2275 or Airtight, or even the Jadis DA60 used if its within your budget. All 3 amps will easily drive the mezzo unless your room is too large.
I would agree at times the tweeter can be a little harsh in mine and supoose that what I am trying get away from, I have'nt heard a lot about Mcintosh are they any good as I rememeber sombody bagging them once,that has stuck in my head for some reason I normaly dont try to think that way,
McIntosh on JM Labs is always magical. I have loved that combo for years.