Bel Canto DAC/Rotel 1072 question

So, here's a self-absorbed and probably stupid question, BUT...

The other day I bought a Bel Canto DAC2 from audiogon. Coincidentally, a few days later (before it arrived), my Rotel 1072 started creating a nasty hum/buzz through the speakers - even when it was turned off. I switched inputs on the amp, switched cables, even took off the Rotel's casing and tightened the screws near the IC sockets. The buzz/hum continued.

Now that the DAC2 arrived, and i have the Rotel working as a transport with a digital coax output avoiding the analog outputs altogether, the hum is gone and the music is back.

My question is: I have no way now of comparing the Rotel with and without the DAC2. Yes, it sounds quite good, but I can't remember if it sounds better than it did before. The Rotel has a BB1738E DAC, while the BelCanto uses a BB1796.

So, should I keep what I have?

Or sell the DAC2 and get a better CD player (under $700 used)

Or keep the DAC2 and get a better cd player/transport?