I went from a Crest Audio power Amp. 450 Watt x 2 to a ADA 1250 x 3. I have the M80s and VP160. When I first hooked my M80s to an external power Amp. the difference was noticeable immediately. Much larger and cleaner. I noticed parts of songs that more or less was muffled at moderate volumes.

At the time I was using a Teac Pro A.V.R. made by Onkyo Integra that had a Toroidal transformer."{100 watts x 7}" The difference was so great as soon as I added external power. I decided it was a must for me personally.