Mcfarland, are you speaking about the Balanced A1 preamp. The A2 has L&R Balance controls as well as a main Volume control.
I own the A1 and, with a decent set of tubes (nothing over $17./each) casts an enormous sound stage. Instrumental detail and location of performers are quite spectacular. Complex classical recordings (Stravinsky Rite of Spring, Mahler Symphonies, etc.), if well recorded, suffer no congestion or smearing. Crappy, tiny sounding recordings (early digital), do sound like...well, crap. So the preamp is not coloring the sound, just giving it to you straight. By the way, for a tube preamp, mine is almost dead silent. Only sticking an ear right to the speaker would you hear a very faint hiss.
Previous balanced preamps I have had were the BAT 3xi, BAT 5i and Pass X-1. (I run balanced into a Music Reference RM-200.) Unbalanced pres have included a modified ARC SP-8, SP-10 and one of the early Threshold items (as you can see from my choices, I prefer an old fashioned mentality for sound).
The only reason for me to part with the A1 preamp is if I were to buy the YS Audio A2. As we see with Chinese companies like Audio Experience, MHDT (Paradisea, Havana) and others, they have the goods to make quality products at affordable prices. The latter two words, along with the phrase "Chinese Made," have come to mean "cheap" in the world of "audiophilia nervosa." Maybe as it relates to some products, but certainly not to this preamp.
8^(