Helo Eagleman -
The noise is most likely caused by a ground loop created by more than one piece of equipment with a 3-wire AC cord. This problem may also be caused by a cable TV connection if you have any audio signal cable connected from the TV (or any associated equipment) to your audio rig. Here is a link to a good explanation of ground loops and how to fix them: http://www.altavistaaudio.com/hum.html
If you ever want to know what the noise contribution of the amplifier is by itself, just unplug the interconnect cables and replace them with RCA shorting plugs in the amp's inputs. Shorting plugs are so-named because they make a connection from the center-pin (hot) to the outer ring (ground), thus "shorting" the input to ground. This will tell you what the intrinsic noise level of your amplifier is, and this can be useful information when you are troubleshooting system noise. A properly operating amplifier should be fairly quiet - there should be only a tiny amount of noise (or none at all) with your ear close to the speaker.
Beyond that, you should keep in mind that the DNA amplifiers run at slightly higher voltage gain than is typical. This means that the noise floor of your preamp may be more noticeable than it used to be, depending on what amp you have replaced. This is not usually an issue, but I have seen cases where a small amount of preamp noise that had previously gone unnoticed became audible (right at the speaker) with a DNA amp.
I hope this helps. Please call me at 760-732-0352, 10-6, M-F PST (California) if you would like to discuss this further.
Best regards,
Steve McCormack
www.SMcAudio.com
