Seabreeze,
I'm a long time owner of an Aleph Os. This amp had been driving a pair of Unity Audio Signature 1s in my second system until my son was born 7 years ago, and my wife "confiscated" the room and turned it into his bedroom. Whatever got retired from the main system got added to this system. I had tried the ARC LS-1, -2B mk II, -3 in this system. As both the amp and the speakers are on the warm side, I would recommend a preamp that are on the cool side. I had since sold the preamps, but my wife mandated that I keep the rest of the equipment. She thinks the midrange is to die for. I've purchased the Aleph P w/ remote, that is the latest version with all the updates. they go pretty quickly whenever they show up on the used market. Make sure it is version 1.7 (I think). I can't comment on the sound as I am waiting for my house remodel to be done so I can get this system up and running. But I do find it annoying that the mechanical volume pot makes this sound when turning. It's like hundreds of typewriter keys tapping at the same time. I checked w/ Pass, and they said that is normal.
If you happened to live in the San Francisco Bay Area, I would gladly bring it over to try on your system as I'm dying to hear how it sound.
FrankC