I auditioned the Cary V12R extensively in my system before "settling" for the AES SixPacs purely due to size. The V12R is just too deep for my rack while the SixPacs monoblocs were of better manageable size. I went with the SixPacs with the rationale that I like the sound in triode mode much better than ultra-linear. For the Cary, triode mode is fuller in the midrange, and has better depth (air) around the voices and instruments. Ultra-linear has more bass, but the mids is a bit more recessed, translating into a false-sense of extended, detailed highs. The highs are there in triode mode, but I was so mesmerized by the excellent midrange performance that the highs went... unoticed. I had to work hard, drawing my attention away from the mids, and focusing on the highs in order to come to the conclusion that the the highs in triode mode has faster attacks and longer decays (translating into better sense of air). Since my intent is to use the solid-state Classe' for bass, I didn't need the higher-power ultra-linear mode and put more focus on the midrage performance. The ARC VT100 running in ultra-linear mode did not fare as well as the Cary V12R in ultra-linear. The Cary is a bit fuller with bigger tone, making the ARC sounded too...thin, hi-fi and too hi-resolution. My impression of the Cary V12R mirrors that of
Stereophile review of Cary V12 albeit, the review is for the original V12, not the V12R version.
Spike