Who tried Class D only to return to S/S or Tube

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.

In my main system now I use Class D amplification. I do rotate between the different kinds of amps to just get different flavors of sound. Right now I have my Jolida JD502P with Tung Sol KT150 tubes powering my Ohm Walsh MicroTall SE. The Jolida does fine with powering them and is a nice space heater in these cold days. With the system/speakers I have I found Class D works best.

I recall that Stereophile put the PS Audio HCA-2 in the 'Class A' 
category... kind of curious how they would rate it today ??

I had one and although my setup has changed a bit...my acoustic memory would have the Class D Audio 470C showing the HCA-2 the door !
For the money spent this amp reminds me of the NAD 3020 that I used with my DCM Time Windows, both of which I bought new at the time.

This amp could easily hold you over till the 'dust settles' a bit in the class D wars...and for next to nothing (relatively speaking) !!  

The way people talk about the older amps from just a few years ago not sounding anywhere near as good strongly suggests that a few years from now class D will sound a lot better than it does now.

This has entirely to do with technology performance curves; if only a few years separates the good from the bad then its simply a fact that the technology is not yet mature and further improvements are already in the pipeline