Doug- Your point on noise floor being lower is probably correct. I suspect that the 990 would have a lower noise floor compared to 970 due to the balanced outputs and higher quality DAC in 990 (vs unbalanced for 970). Were you using the balanced outputs from preamp to amp when doing your noise floor testing? Remember, I've already lowered my noise floor considerably with balanced power transformers supplying all my gear. It could be that it could go even lower with fully balanced preamp, interconects and amps- I don't know. I'd like to try this, but with considerable recent investment in amps that do not have balanced inputs, it will have to wait. BTW- My understanding is that it's not only the inputs that matter, but the entire amp/preamp set-up needs to be balanced throughout the electronic architecture (and I think this is why the new Outlaw stuff is soooooo popular- they did it and are not charging an arm and a leg for it).