Hi Jeff, I suspected as much... The amp was probably a pair of M501 monos or M201 monos... Unlikely to be the M301 monos, unless each chassis weighed about 95Lbs. Each M501 chassis instead might weigh some 20Lbs, and is about 7.5 inches wide only. is
M501 was a basic implementation using the ICEpower 1000ASP module. Very powerful and clean, but.... Subtlety and high musicality were not its main features. I heard the M501 several times at RMAF.... I deemed its sound not to be involving at all... ANd yes, treble can have a rather cold quality to it, which also means that if complex treble passages go through M501, you might hear more than a bit of harshness.
For the ICePower 1000ASP to sound good, it requires either the fine work done by Stronczer with the REF1000 Mk.2, or the PFC rectifier and custom power supplies that Rowland used in its higher end amps based on the same module, such as the M312 that I had for several years.
Rowland does market an external PFC rectifier called PC-1 which is compatible with M501. People who used PC-1 on M501 report the sound to be completely different, and to have approached M312.
Regardless... All of this is in the past.... M201, M501, M312, M301 are all 3 or four generations old. Class D has made significant strides since these 4 legacy Rowland amps, the only one whose sound I consider excellent for today's standards
is the M312, which shows up very seldom on Audiogon.... Its owners tend to keep it for a long time.
Regards, G.