Yogi, I subscribe to the viewpoint that hum isn't a function of tubes, but rather poor design. However, it does come down to tolerances. Sand amps tend (generalization here - beware) to be sensitive more than tube amps. That is, they achieve full output with a lower input voltage. They also...
When you say "external inputs", are you referring to the 5.1 (or perhaps 7.1) direct inputs? So your chain is: DVD Player -(RCA)-> ASL2004DT -(2 of 7.1 direct inputs)-> 3802 -(preouts)-> Proceed (yum, by the way). If you replace the DVD player with another device, you don't get the...