450 Pound Monobloc Amplifier

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

Mitch4t, the 54Lbs per chassis amps from Rowland (M625 and M725) are running in class A/B rather than class D.

Mapman, there is starting to exist rumbllings that recent amp implementations based on new modules may constitute entirely different kettles of sonic fishes. Definitely, some formal comparative reviews of some such creatures would be welcome.

.

Highly efficient, compact, light weight, 1500 watt DC switch-mode power supply provides optimum voltage regulation for all circuits and operating conditions, and allows for quiet operation over a wide range of AC mains power sources.

Guido...above is the quote from the Jeff Rowland site regarding the 725 monoblocs. Is the power supply switching technology mentioned there similar to the class D switching amps? I've heard class D amps referred to as 'switching' amps. Is this Rowland a 'switching' amp? No big power supplies in the Rowland to be seen.

Looking at the naked chassis before the innards are put in the amp, it looks like at least 60% or more of the weight is solid aluminum billet chassis.

Click Here To See The Aluminum Chassis...(scroll down when you get to the page)
.

Hi Mitch4T, all current Rowland amps and pres are based on switch mode power supplies (SMPSs). However this does not mean that the amps are necessarily running in class D. For example, look at the specs for M625 stereo and M725 monos...

http://jeffrowlandgroup.com/kb/categories.php?categoryid=203

and

http://jeffrowlandgroup.com/kb/categories.php?categoryid=208

G.