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Posted By: thyname Noise from my Axioms when.... - 04/16/06 05:31 PM
...playing a DVD player. More specifically: I tried today to connect a Sony SACD/DVD player to my Rotel RC-1070 preamp with analog audio interconnects and to my Samsung DLP HDTV with components/s-audio and simple video cable. I hear a very annoying noise coming out of my Axiom speakers while playing a DVD!! Tried switching all cables with no luck. Meanwhile, no noise when I play my Rotel RCD-1072 cdp as I always do, it is only when tv is on and dvd player playing. When I disconnect video cable, I notice no noise. SACD plays fine as well. It drives me crazy!! Am I doing something wrong here?? I even tried it with my Panasonic DVD recorder/player, same thing.
Posted By: JohnK Re: Noise from my Axioms when.... - 04/17/06 02:07 AM
Skerdi, as you've noticed, not a ton of ideas forthcoming yet, and what you describe is puzzling. There's no problem playing CDs(without the TV, of course)and a problem with all three types of connection to the TV, which disappears when the video connection is removed. Is this "annoying noise" like a ground-loop hum which goes away when removing the cables breaks the loop? Of course if there was no problem when you did this before, it's curious that a ground loop would suddenly appear.
Posted By: thyname Re: Noise from my Axioms when.... - 04/18/06 12:18 AM
Hi John; I did not go too much in details for my situation, always thinking that nobody would remember my setup "prior" to the problem: I have moved to a temporary rental apartment provided from the developer until the condo I purchased is built (they expect it around June), thus my "old" setup in the new conditions. The only change is that I don't have satellite tv anymore (not my choice) but Cox cable, at least until I move to my own place.

Also, from some research I did, it seems that cable signal is the problem. It appears like the cable signal causes a "ground loop" hum to my RC-1070 transmitted throught my TV. I called cable company as well and they were not that helpfull. The good news is I can play CD like before, can play dvd without noise but only if I unplug all cables going from the cable box to the TV. A little inconvenient you can see. The other good news is that I will not stay here forever (scary to think about another move!!). However, any advice on how to get rid of this hum would be appreciated.
Posted By: JohnK Re: Noise from my Axioms when.... - 04/18/06 01:48 AM
Skerdi, I'm astonished(not)to learn that the cable company wasn't helpful. Assuming that's the cause of the noise(when you disconnected the incoming TV cables the noise stopped)there're cable TV isolation transformers to put on the cable input(before the box)available from sources such as Parts Express. Another way is to break the loop at the video cables between your player and TV. The idea would be to have the center conductor(s)making contact in the TV input, but the outer shield(s)not making contact. Partially withdrawing the cable(s) so that only the center conductor is still making contact, to verify that the noise stops, could be tried. Assuming that it works, little strips of plastic film or even paper could be fashioned to keep the outer shield from making contact even when the connector is fully inserted into the TV.
Posted By: pmbuko Re: Noise from my Axioms when.... - 04/18/06 02:31 AM
You stole that trick from McGuyver, didn't you?
Posted By: thyname Re: Noise from my Axioms when.... - 04/18/06 02:47 AM
Thanks for the advise John. However, I need to use component video cables from my HDTV DVR cable box to TV, to take advantage of HD. I can't see how to do your trick with those kind of cables.

I am trying to work something out with my line conditioner (Belkin PureAV) meanwhile. It has a cable in and out socket (two sockets), and they must server some purpose I'd assume.
Posted By: HomeDad Re: Noise from my Axioms when.... - 04/18/06 02:50 AM
It's possible if you run your cable through your line conditioner then back out to your TV the problem may resolve itself.
Posted By: JohnK Re: Noise from my Axioms when.... - 04/18/06 03:06 AM
Skerdi, I wasn't referring to the cables between the cable box and the TV(although the same idea would apply), rather the ones between the the TV and the player. Presumably the noise is getting to the speakers by way of TV to DVD player.

Sure, try the Belkin device, in case it happens to include an isolation transformer on the cable input/outputs(and passes HDTV).
Posted By: thyname Re: Noise from my Axioms when.... - 04/18/06 05:18 PM
Thank you guys for the advise, it seems that I found a partial solution: I used my Belkin power conditioner and the hum is not that loud. It is still there but not as much, I could not hear it while sitting on the sofa and watching a movie, but I could hear it if I mute RC-1070, or if I am changing DVDs. HDTV works fine through Belkin line conditioner. What I did is run the coaxial cable from the cable splitter to Belkin Cable In jack and then another coaxial cable from Belkin Cable out jack to the TV. I will try Jack's advice (sorry, got the meaning of your post but after I posted mine), through a simple video cable and not through s-video cable I now use from the DVD player to the TV set.
Posted By: n8wrl Re: Noise from my Axioms when.... - 04/18/06 06:45 PM
As a ham radio operator, tracking down these sorts of signal problems is very common. My approach is to disconnect cables one at a time until it goes away. Another approach is to disconnect everything and plug things back in one at a tiem until it starts. I recently had to apply these techniques to hum that eventually was caused by a ground loop with my subwoofer.

There are just too many devices in our setups not to take a systematic, one-step-at-a-time approach to identifying the culprit.

-Brian
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