Loud Hum from DNA 0.5

Thanks for the input. Yes, it's the same receiver used prior to the repair. The system was essentially untouched other than using the receiver to power the speakers while i was waiting for the repair. I guess I'll have to wait until Monday to call McCormack.

Also, I'm using Vandersteen 2Ces so I can't look at the drivers.

Also, I should clarify that the hum is loud enough to make the amp useless. And regarding the preout noise, prior to repair, there was no hum and prior to the DNA 0.5, the Rotel amp produced no hum.

Hi Taylormade2 -

Sorry to hear about the problem with your DNA-0.5. I have no idea what work was done on your amp, but it seems possible that the factory updated the Earth / main-board ground path while doing the repair work. This would normally be a good thing, but it may have gone awry in your particular setup.

If the amp were "broken," I would expect to hear noise constantly, even with no input cables connected. You say that the noise disappears if you remove the interconnect cables, and this suggests a ground loop. Try "floating" the earth ground connection on the amp by using an AC "cheater" plug (3-to-2 connection adaptor). These are available at your local hardware store. In addition, if you have any kind of an audio connection to a cable TV video system, disconnect it. If the hum disappears, you have been dealing with a ground loop. For a more complete explanation, go here: http://www.altavistaaudio.com/hum.html

Good luck!

Best regards,

Steve McCormack
www.SMcAudio.com

I tried disconnecting everything from the receiver other than the DNA and the hum is still present. The AV receiver only has a 2 prong plug. I can try getting the converter for the DNA to see if that solves the problem.