Streaming Preamp

I have been upgrading my bedroom system which started out with just the Cary AiOS and a pair of SCM 7's.
Looking for a streaming preamp and the three I am considering are:
AVM Ovation SD5.2
Musical Fidelity m6 Encore Connect
Cambridge Edge NQ
I am unable to hear each in my system and just looking for some general info from "sound" to functionality. Also, any other recommendations.
Thanks
Scott
System:
Cary AiOS as pre 
Parasound A21
ATC SCM 19's (sound anchor stands)
SVS subs
Morrow cables
Shunyata PS8