Ground Loop Hum (1 Viewer)

[WilliamJay]

I am demoing a Jolida JD 502B integrated amp to power my main speakers. Is sounds great. However, when connecting the Jolida to the pre-outs of my Denon 2802 so that it could be used as part of my HT setup, I noticed a loud hum coming from the speakers and nothing else, no dialog was coming through. The hum disappeared when I disconnected the coax cables from the cable box. What can I do to eliminate this hum?

Also, when I played a DVD, although I could here dialog coming from the front speakers, all 5 of my speakers were producing much less volume than they should at the indicated volume level on the Denon.

Any help would be greatly appreciated.

Thanks,

Bill

 

[John Robert]

Cable boxes are notorious sources of ground loop problems. Do a search here or at AVSforum for many issues and solutions...

 

[Kevin. W]

You need a ground loop isolator(Radio Shack) to solve the hum. Also you need to recalibrate your setup with a sound level meter now that you've added an amp. I think it has something to do with Input Impedance/Sensitivity of the amp and the output level of the Denon(someone else may want to jump in hear). Or the fact your using a tube amp at 60w per where as your Denon is 90w per.

Kevin