The Bat Vk-500 was no match for the Krell Ksa-250 on my Apogee Duetta Signatures...it strained and became harsh. It was pretty good amp over-all though and I would still rate it 4 out of 5 in the big SS amp camp with the Krell being a 4.5 because of a slight SS grain even though never under strain.
Dave
Dave