450 Pound Monobloc Amplifier

In theory, I suspect the difference between best Class D and Class A amps may still be bandwidth, like Kijanki says. Those attune to things happening at the very upper frequency limits of human hearing are probably most likely to notice any difference there. But over time I suspect even that would become a non-issue as technology improves, unless there is some hard law of physics out there that imposes a barrier for the long term.

The bandwidth limit causes phase shift in audible range possibly affecting harmonics summing. My amp, for instance, has -3dB at 65kHz causing 20deg phase shift at 20kHz. Mentioned Rowland model 725 has bandwidth of 350kHz.

I'm interested to see if Stereophile or some other independent publication puts the new Pascal Class D amp from D-Sonic on the measuring bench to see how it compares to recent better Icepower based amps in terms of frequency response/bandwidth.

I don't believe that an amp has to be heavy to sound good. But, I do know to get rated power over the specified bandwidth, you need a serious power supply supply. you can't get around it. Which means that the tranformers must be huge and heavy. Large storage capacitors aren't cheap for the higher rail voltages necessary and they are heavy also. There are "tricks" that some manufacturers use, but they are just that, tricks. However, that is not to say that lower powered amps aren't wonderful. They are. One just needs to be very careful as to what they will be driving and what amount of consistent power is required. I read a review about the Dan D Agistino momentum amps and I would love to hear them. This guy, knows his stuff. I bet they are really great.

Mapman - this question should be addressed to more experienced Audiogoners who have chance to compare them at shows. I can only comment on technical merits.

Minorl1 - no tricks, just different technology. Transformer operating at high frequency can be 10x smaller. For the same reasons capacitors don't have to be large. Smaller caps work great for filtering of higher frequency while voltage stability is handled by regulation. In comparison traditional supply doesn't have any regulation (line or load) and operates at 60Hz. Both conditions require huge amount of capacitors to keep voltage steady under momentary load and to filter out low 120Hz.

One review of my class D amp praised it composure during music peaks (orchestra forte) - that's what load regulated supply brings. In addition so called linear supplies are in reality primitive switchers operating at 120Hz and polluting with high current spikes. Rowland switcher has power factor correction and presents resistive load with smooth current. Jeff Rowland perhaps explains it better:

http://jeffrowlandgroup.com/kb/questions.php?questionid=144