I've heard very good things about the 585's if you modify them. I would think that the mono's would be better at low impedances and the 5802 might be better at higher impedances. Sean
A local shop had the 585's on a pair of Mirage M1's back when both were new to the market. I don't recall all the details as to their sound, but do recall that they were up to the task in the power department. Stereophile rated the 585's Class B which was very good in those days.
I no nothing about the 5802 or any of the newer Adcom stuff so no help there.
Wes..I think you are confusing the 565 monoblocks with the 585LE.The older adcoms with 3 digits use bipolar transistors.The newer models with 4 digits use mosfets.I've had the 5500,5503 here at home.And own the 585LE..which is the equal to a set of 565 monoblocks.From listening to these versions..I can tell you the mosfet versions are no match for the bipolar versions with low impedences.I really didn't care for the mosfet versions but after spending time with the older adcoms.I've discovered the bipolar versions performance is on another level. Newer is not always better.Never have I seen the distortion lights come on with the 585LE.Where as I've seen the 5500,5503 go into clipping with a pair of Paradigm studio 100v2s .This happened while watching a movie and one of the amps actually shut down.
Before this 585LE shuts down you will likely melt some tweeters! So if I had to choose between the 5802,565 monos or 585LE.It would be a toss up between the 565s or a 585LE depending on the space in the room.