Questions about Aragon 2004 MKII

Hello All,

I recently purchased an Aragaon 2004 MKII amplifier. I have it mated with a Bryston BP-20 pre amp and an Arcam CD72 cd player. Wharfdale E90s are the speakers I am currently using. I am using the Acoustic Research interconnects that were designated as the "$20 high end interconnect" in Stereophile a few months back. Also using lamp cord for speaker wire. The previous amp I was using was an old Hafler dh-220. Is it me or does anyone else notice that the 2004 mkII rolls off the high end frequencies? I never had this problem with the old hafler and am somewhat suprised to say that I genuinely prefer the sound of the hafler over the Aragon. I am hard pressed to find any benefits of this aragon. The only positive I can think of is its uncanny ability to run cool. No stove top heat radiating out of this unit. Could my specific unit be an anomaly or is this quite characteristic of this brand. Also does anyone have any idea of what kind of the frequency response curve this aragon has?

Thanks in advance