Tube Preamp for Mcintosh MC501 Monoblock

McIntosh's own C2200 tube preamp will match it perfectly.

I have the 501's and have been using them with an older ARC LS2. I have since purchased a Mark Levinson 390s with a direction balanced connection into the amp with incredible results (makes me want to bypass using a preamp altogether). However, I do plan to upgrade my preamp as I am incorporating HT with my 2-channel (swapping IC's gets old after a while). So far I've have been considering the BAT VK-51SE and Aesthetix Calypso. The 501's are wonderful sounding amps, and having heard them without a preamp (depending upon what your goals are) I would look to find the most neutral and transparent preamp that you can afford.

If you want the best, try the VTL 7.5. sounds devine with the MC 501's.

WOuld there be impedance mismatch with BAT & CAlypso into a 10K input impedance amp?

Aesthetix recommends a 10k or greater load which the MC501 can manage (10k unbalanced, 20k balanced). The BAT has a very low ouput impedance (200 ohms). There should be no issues running either of these preamps with the Mac as it's input impedance is high enough to not load down either preamps output stage.