Audible differences in amps may also be due to design philosophy. These may be shaped by the experiences of the manufacturer or the designer. My Denon has a noticeably softer sound than my Onk likely because Denon traded off higher slew rate (and maybe even bandwidth) for greater stability. Maybe Denon had historical problems with stability (which can be caused by "esoteric" cables), created a reference design to ensure such a problem is never repeated and the design is now forever etched in all Denon products.

House of the Rising Sone
Out in the mid or far field
Dedicated mid-woofers are over-rated