I got the 555SE today and did a quick audition only as I'm busy, but will have more time on the weekend. In short, this amp is the real deal. Dead quiet, imaging, separation of instruments and dynamic, it's the whole package. I'm running it with the Halo P5, Morrow Ma5 cables, and decent Wireworld speaker cables. A Bifrost DAC and Nad C565BEE cd player, so decent supporting gear, but I am impressed with this amp.
On power up, all you hear is a little relay click as the amp comes on line, and of course the house lights dim upon powering it on. There is no 12 volt trigger so you have to turn it on manually, but I think I can make an outboard box that will accept the 12 volts from a trigger cable and power up the amp using a relay.
Adcom has been pretty quiet the last several years, so it's nice to see they can still put out a great amp. I'm replacing a Nad C375BEE and I've also had a Halo A21 a year ago. Oh, and the 555SE sounds better than the GFA 5400 I've got too, though that amp is 19 years old.
