John, in general the answer is no, weight is not a factor in amplifier performance. High performance can be achieved in amplifiers that weigh a lot, and in amplifiers that weigh relatively little. In dividual designers make certain technological choices that end up leading down particular technologies, topologies. . . and weights. In the end, there are excellent amplifiers at all weights, and horrible amplifiers at all weights.
In the particular case of the JRDG 102, the designer wanted to achieve a high degree of performance for a chosen constraint. . . it was not weight. . . but an entry level target price of $1500. He used class D amplification and regulated switch mode power supplies that are extremely energy efficient, hence the very low weight. Whether Rowland achieved his price/performance goal on this particular product or not can be decided only by using one's ears. Unfortunately a scale won't help.
Will JRDG 102 outperform a Levinson 331? Perhaps possibly, but I truly doubt it. The 331 was designed with more ambitious goals. and it is priced 3 times higher than JRDG 102. While price alone is not a particularly good gage of performance, it is somewhat a better indication than weight.
On the other hand, if your budget can go as high as the $2K for the 331 currently offered on Audiogon, I suggest you also have a look at some of the bel canto Ref 1000 monoblocks available on Agon. I have reviewed one of these little wonders. . . and they are quite wonderful. . . and yes, very powerful as well. .. . and won't turn your living room into an oven. . . 331 runs in class A, which means it dissipates a huge amount of heat. . . not great for Houston Summers. G.
