I am now trying to setup my first ever 5.1 surround sound but I am going to start with front tower speakers and a really good Receiver and Amp. Why are some Amps so heavy? Some are over 70 pounds! Like the Emotiva XPA-5 XPA-5 | 200W x 5 | Emotiva Audio | High-end audio components for audiophiles and videophiles, spanning 2-channel music systems, as well as 5.1 and 7.1 home theaters. Products include multichannel amplifiers, stereo amplifiers, and monoblock amplifier The Marantz MM 7055 is less than a wimpy 35 pounds and cost 300 dollars more! Marantz US | MM7055 How do the lighter Amps compare to the heavy weight Amps is terms of quality of sound, heat build up during long operations, and overall longevity? I thought the heavier ones would be better. Is that the case with the Amps? If you won a raffle and could only pick one of those two, which would you pick? And why?