Amplifiers weight

The answer you are looking for is EXACTLY here by Nelson Pass:

https://www.passlabs.com/press/power-supplies-commentary-consumers

As noted, the size of the transformer is important. Inductors too, and heat sinks are heavy. The bigger the heat sink, the lower the operating temperature, for given heat dissipation.

The amount of real estate inside the enclosure is also important. If the big electrolytic caps are close to either the output transistors or the rectifier, or their heat sinks, they age prematurely. Obviously big enclosures weigh more.

If you live in a rich radio environment, thick metal is a good shield for your delicate electronics, although good layout can substitute. So again, all things being equal, heavier is better - the only problem is that all things aren’t often equal.

Finally, if a guest stubs his toe on 100Kg slabs of aluminum, that toe stays stubbed. Better that than the amp.

Weight has nothing to do with anything unless you are carrying it up 3-4 flights of stairs. So either buy a lighter amp or work out more. 

This thread carries no validity until Kenjit chimes in. 

I have never heard a class d amp, or for that matter, a Rotel, sound musically engaging. Get the Anthem or Parasound. I love my 65 lb Luxman class A!