A little late to the discussion, but my two cents
I've experienced most of the vintage brands 70s thru the early 90s... and fell in love with Belles amps... at the time I was able to actually listen/ compare them side by side in my search for a new amp to replace the Mitsubishi DA-A15 and preamp I had sold. LIstened to :Phase Linear, Mac, Carver, Yamaha, HK, Pioneer,Luxman... can't remember the rest, sorry getting old lol .... against a variety of inputs and speakers ( TOTL Dahlquist, Yamaha, Klipse, Infinity, Carver (yep) , JBL, B&W, and ML I think), the Belles 450 was far and away the best of the lot.... it just revealed what was played without adding or subtracting anything from the source... and so musical it was startling at times....rock, classical, blues, blue grass.... didn't seem to matter..... just my opinion and those at that store at that time... your results may vary lol... too bad I sold that amp a few weeks ago for a song....