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ken stokes
11-05-08, 06:42 PM
I had two additional TVs added to my system today and now I have a major hum in my main system. To fill you in
I was ruining three TVs with one HD DVR.
Today I added two TVs which required a "Multi Switch"
I now have a loud hum on my main system (not new service)

I tried resetting the main unit,an HR-21
I tried disconnecting the boxes on the new TVs
I tried reconnecting the wires on my sound system consisting of:
Tag PrePro - Theta Amp - Five Aerial Acoustics Speakers - Denon DVD - HR

Any suggestions are welcome!

Thanks
Ken
curt8403
11-05-08, 07:05 PM
I had two additional TVs added to my system today and now I have a major hum in my main system. To fill you in
I was ruining three TVs with one HD DVR.
Today I added two TVs which required a "Multi Switch"
I now have a loud hum on my main system (not new service)

I tried resetting the main unit,an HR-21
I tried disconnecting the boxes on the new TVs
I tried reconnecting the wires on my sound system consisting of:
Tag PrePro - Theta Amp - Five Aerial Acoustics Speakers - Denon DVD - HR

Any suggestions are welcome!

Thanks
Ken

get a cheap electrical outlet tester and test all your electric outlets/ there is a loose connection (Floating ground or floating neutral) somewhere in your system
David MacLeod
11-05-08, 07:06 PM
running out of regulated power?
BattleZone
11-05-08, 07:09 PM
Curt's got it. Some part of the new section of the system introduced a ground loop, which means that everything isn't being grounded back to the same point on the house. Either you've got an ungrounded outlet, or the neutral is touching the ground.
Justin23
11-05-08, 07:15 PM
Three TV's with one HD-DVR?!?!?! How was the PQ?

J
AntAltMike
11-05-08, 08:31 PM
Search for "ground loop isolator". They cost ten bucks each, do not create a safety hazard, and make most hum symptoms go away.

http://www.cencom94.com/gpage.html8.html
joe diamond
11-05-08, 11:43 PM
I'll take a shot,

The original rig had a ground block that was grounded. when the multiswitch went in it did not get grounded so the ground loop is produced by the various sets on different circuits experiencing different ground (potential?).....over my head on the engineering.......See if the multiswitch is grounded and if not try to ground it,,,,,,,,see if the hum goes away. Conversely.... if the original rig was not grounded and now is try disconnecting the ground to see if the hum goes away.

From there you are back to what the guys mentioned above;ground loop hum.

Joe
DJTheC
11-06-08, 05:28 AM
Wait! You're all wrong! If it's humming, you must teach it the words! You can even harmonize with it!
joe diamond
11-06-08, 06:51 AM
It is a..............hum bug!

Joe
DJTheC
11-06-08, 10:41 AM
It is a..............hum bug!

Joe

Bah
jimmyv2000
11-06-08, 10:55 AM
tho the OP:
are you hearing this hum without an HDMI CABLE?
like using red and yellow audio cables?
on one of my sets i had an audio hum and i bought an Hdmi cable and the problem went away:D
MY 2 cents
Jimmy
Cmnore
11-06-08, 02:03 PM
It could also be a bad set of cables. Punish the cables and exploit them. :^D
BattleScott
11-06-08, 04:39 PM
Are you sure it's an elecrical hum and not a vibration hum from the HR-21. When I got a new TV table last year I had to put foam rubber pads under the HR20 to silence the vibration. The cabinet shelf it was on was ampifying it so bad you could hear it other rooms...