I have made a few changes since I last had these two power amplifiers out and playing. I had a chance to do a listening comparison today.
preamp is a Musical Fidelity A3cr;
source is a Yamaha CD-S1000 SACD player;
speakers are Orpheus Apollo V1.
I played both amps for a few hours each, one hour of warm up, and one hour of listening.
First == Yamaha B2. - It is an authoritative amplifier.
There is a lot of grunt, plenty of power. It "feels" more powerful than the Sony, even though both amps have the same 100watt rating. Midrange is quite forward and very good, bass is deep, good, tight and controlled. The B-2 throws a BIG soundstage, and has excellent imaging and separation.
You need to pay particular attention to the surrounding components with the B-2. The B-2 does sound very fine, however perhaps more system synergy is required. I still think, the best I have heard the B-2 was with a tube preamp. That's does not mean the B-2 is not a brilliant performer, just for my tastes the tube pre brings a different yet more musical experience with the B-2. Something like an Aesthetix Calypso line stage preamplifier I imagine would be stunning with the B-2.
Second == Sony TA-N7B - Amazing sounding amplifier.
This amplifier just works better in my system than the Yamaha. It demonstrates superb control, and delivers truly composed power delivery through the entire audio spectrum. Perhaps the Sony just loves driving the Orpheus?, as the speakers sound so nice with this amplifier. The preamp is a lovely match also. It is not as forward in the mids and highs as the Yamaha, the B-2 seems 'brighter" when you put it into the system. Perhaps as the Sony has cascode v-fet + bjt's it is more forgiving with respect to preamplifier choice. The A3cr works brilliantly with the N-7B
Both amplifies are quite complex in design. Both amps demonstrate exceptional linearity, speed, performance, great dynamic range, yet both have a unique tone and richness you only get with these types of amplifiers.
Music --
Mark Seymour - Daytime and the Dark
Eva Cassidy - Live at Blues Alley
Mighty Sam McClain - Give it Up to Love
Mike Oldfield - The Songs of Distant Earth