Summary:
Driving Apogee Studio Grands require both current & voltage. The Apogees are extremely revealing of amplifier characteristics as well as having the ability to create the worst case scenarios for amplifiers. The Legacy Monobloc's are the most transparent amplifiers I have encountered for this speaker. The MC 275's are wonderfully seductive in the midrange when run in mono, however they bloat the midbass, imparting a bass heavy quality, resulting in a slow pace.
The Pass Aleph 2 are wonderful amps. They produce the finest nuance of detail in the soundstage, however when asked to produce high volume they flatten out dimensionally. They also run extremely hot ! The Legacy Monobloc is quick, quiet & cool. Almost the fine nuance of the Pass with much greater ability to produce volume. The music just sounds more relaxed at higher volume. Soundstage height is exceptional, width & depth are pretty much whats on the recording. These should be all the amp anyone needs.

Strengths:
Clean, effortless power, runs cool, modest weight

Weaknesses:
Hardens slightly at very high volume in difficult loads.

Similar Products Used:
Pass Aleph 2 , McIntosh MC275 as Mono, McIntosh 7200

Summary:
I have two Monoblocs drivin my Legacy Signature III speakers. This week, I am using a Dynaco PAT-5 preamp that I built 21 years ago, with good interconnects and good speaker wire (no endorsements from me on cables). I will next try and Accurus preamp, and then I am thinking about trying a Legacy preamp. My mainstay tube preamp will go unnamed, here.
Many fun-loving readers would be very pleased with my PAT-5 performance...
Remember these great-spec budget kits from the 1970s? And to have something I built lined up with such fine modern instrumentation...

I'm unsure how these Monobloc amps sound, in terms that I see used in this forum commonly. Much of my material sounds beautiful. My Peter White "Collection" CD is a production gem, revealed in glory on this system.

I've heard so many amps, but so rarely side-by-side and in my own home. On some days, I have fooled friends into thinking (during blind testing) that a $300 Sony receiver sounds better than a $3000 power amp and $2000 preamp. I have lots of other hobbies, and may never get a bunch of other amps here to really A-B them for differences. I figure I am at a quality level now that I can get on with listening. I have so many CDs and albums, and so many moods ... I can't be worried at this point whether some fine Bryston 7Bs would outshine my Monoblocs. I truly think I could learn to love so many products.

I must admint, I do, like many of us, consult these postings in search of support for my purchase decisions. It is an insecurity on my part which I am working through. Admitting it sends me speedily on my way to growth.

On thing seems clear with the Monoblocs, and that is that they are good enough to keep me feeling very very good about my sound. I'm thinking about getting two more and going with horizontal biamping. Just for the fun of it. It is a wonder to even have equipment of these specifications.