Does anyone have thoughts on any major differences between these to amps, (sound quality) As far as the Mac, I'm referring to later issues. Would one have more musical, tighter bass, or more transparency, etc...?
The amp / speaker synergy is so vital. What are your speakers?
When I tried them on the stats, the vk-55 sonic signature is that magical glowing glass/ electrostat midrange that has become mythical. Mac sounds SS compared to BAT. It has better dynamics and bass control. It retains some of the tube texture compared to actual SS, but is not nearly as sweet as the BAT.
Depends on what you are looking for.
For electrostat owners who like the sweet tube sound, VK 55 is as good as you are going to get. If one spends more $$$, the amps try to be neutral, but lose a lot of the midrange magic. Try yourself, of course, as this is all experiential.
I'm using Monitor Audio Studio 6 in a 13' x 9' room, @ Martin Login Gratto subs.