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Loud Hum from DNA 0.5

I just had my DNA 0.5 serviced at McCormack Audio for a blown capacitor. Now that I have hooked it back up to my system, there is a loud hum in my speakers. This never occurred before. It doesn't occur if I unplug the preamp input cables and changing the outlet didn't make a difference either. I even tried another set of interconnects and that didn't make a difference either.

The preamp is a Yamaha AV receiver and it has no known issues. I have no other amp available to me right now to hook it up to verify that only the DNA 0.5 is causing the problem.

I'm hoping someone here can make suggestions. Where the amp is being used is not my primary residence. I use an integrated amp at my home and have no way of testing this in my personal system.

Thanks!
taylormade2
taylormade2 OP
19 posts
 
In reading over the counter point article, the DNA is the only component with 3 prongs. The DVD player, AV receiver and TV/Cable box only have 2. Even with the cable tv disconnected from the wall, the hum persists.
taylormade2 OP
19 posts
 
I stand corrected! Thank you so much Steve! I had disconnected the cable tv from the back of the cable box but when I pushed it back on its shelf, the cable was still in slight contact with the connector. I realized that if I removed the coax cable away from the cable box, the hum disappeared. Looks like I need to get a cable TV ground.
taylormade2 OP
19 posts
 
I just discovered that the coax for the tv was still in contact with the connector on the cable box. After removing it completely, the hum went away. Apparently, I need to get the cable TV grounding filter.
taylormade2 OP
19 posts
 
sorry about the double post...my 1st one didn't show up at first.
audphile1's avatar
audphile1
4,919 posts
 
so that hum noise was THAT LOUD????
I had the same issue within my setup. It was humming because of the cable tv coax cable, but it wasn't that loud. Anyway, look for ground loop isolator. 1 example is the Mondial MAGIC(Mondial Antenna Ground Isolation Circuit) box. YOu can find similar products cheaper. I bought this one sometime ago.
Doesn't degrade the picture quality on my Hi-Def and the hum is completely gone.
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