Grayhound,
Maybe the DVA4/2 and 700 sound slightly different? I found the 400R to be warmer sounding. I thought the bass was tighter and more defined with the 4/2. I have not heard 1.6s before, so maybe we are comparing apples to oranges? I have not had much time to listen lately. I will continue to report my findings as I go.
Thanks!
I felt that the 600R's bass was more musical and had more thump. The DVA has tighter bass though. The R series are very neutral sounding with the stock tubes. The AVA Synergy and DVA 700 have a bit more warmth and sound a bit darker but not overly so. The 600R did not play nice with my preamp. The high frequencies were too hot. But in the 3 other systems that I have heard the 400 and 600R's (2 with Magnepan 1.7's and 3.7's) that was not the case. The amps sound great. It is all about personal preference and system matching. A three lines of AVA amps sound great. However, the new Mono Blocks reign supreme. They are a cut above the rest. I wish I had the money to buy a pair.
NightFall, the 1.6's have a mid bass hump compared the the 1.7's. Bass is smoother in the 1.7's. The 1.7's sound more coherent and have more pleasant and detailed high frequencies. I prefer the 1.7's but some people like the mid bass hump of the 1.6's.