ATC SCM40A speakers

Ran ATC SCM 40A for 3 years, then gifted them to a friend.  They are fabulous and reveal each improvement made in front of and to them (Gaia ll footers).  
They provide immediacy of attack, space around vocals and instruments, are dynamic and sound stage well.  

They do not like tube preamps IME.  Tubes were too slow.  They can be a bit merciless with bad recordings.  They are not aggressive.  Only revealing.

Replaced them with ATC SCM 50A.  Best of luck.

admranger   I do not know your particular amp, but I do know ATC transducers.  They can be quite demanding and particular, wringing the life out of respectable power.  I’ve a pair of SCM 20s run by a Luxman 509X and they need all of it.  
125 wpc of solid stable Luxman current.