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#39674 - 09/27/02 08:12 AM Request for help with TV induced noise
applejelly Offline
Gunslinger

Registered: 12/20/01
Posts: 116
Loc: Syracuse, NY
Got my 950 yesterday. I have hiss issues, which I stated in another posting, but I have an even bigger problem right now.

After installing the 950 into my system, I began to power things up. I knew I was in trouble when the first thing I turned on was the TV and TV was making some buzzing type noises: put your each to the TV and you hear it, nothing from say 10' feet away. Well sure enough when I turned everything else on, the terrible buzzing is now coming through all the speakers - very audible with nothing playing or a quiet part of a movie.

Here is where I am looking for help from fellow Outlaws. I am using my TV as a monitor, so I only have 2 connections to it: composite and S-video in. If I turn the TV off, the buzzing goes away (hard to watch movies though). The TV is a tubed 27" JVC. The buzz is even coming out of the TV's speakers (with TV volume set to zero), but at a low enough level to not be audible from a few feet away. Switch the TV to its tuner input, and the buzzing through the TV's speakers is greatly reduced.

I tend to think I am getting transformer noise from the TV, but I guess it could be ground hum related too. My TV source is an ungrounded attic antenna into the VCR with a ground buster between the antenna and the VCR (which cured my ground loop hum that I had previously). I am not sure if the noise is getting into the system through the ground on the video cables back to the 950 (I can check this tonight my disconnecting the composite cable. The S cable is connected directly to the DVD player.) or is it a radiated noise problem where some of my other cables are acting as antennas.

Either way, I am looking for ideas to help troubleshoot this and make it go away. My first though is noisy AC which is making the TV noisy. Anyone else ever have this problem? Did a power filter solve this?

Thanks for your help.

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#39675 - 09/27/02 12:07 PM Re: Request for help with TV induced noise
Smart Little Lena Offline
Desperado

Registered: 01/09/02
Posts: 1019
Loc: Dallas
Applejelly, Did your problems with ground hum start when you purchased the VCR? I notice the antenna runs through it first. As one ‘elimination’ step to reduce your probabilities, - you might attempt bypassing the VCR completely on the chance there is an interaction centered in that unit, before digging deeper, into power conditioners etc?

I had my old JVC with the 950, before the 60” display for several weeks, (also in use before I added the Panamax) with no problems.

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#39676 - 09/27/02 12:44 PM Re: Request for help with TV induced noise
applejelly Offline
Gunslinger

Registered: 12/20/01
Posts: 116
Loc: Syracuse, NY
I've had the VCR for years. I did try disconnecting the RF video cable from the wall and buzz didn't change. I will try removing the VCR tonight as well as disconnecting the video cable(s) from the TV.

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#39677 - 09/27/02 02:27 PM Re: Request for help with TV induced noise
jcmccorm Offline
Gunslinger

Registered: 06/06/02
Posts: 73
Loc: Madison, AL, USA
Hey Apple, I'm afraid I can't help you with your problem but I can add to it...

I use the TV as the monitor for viewing the 950's menu (front projector for DVD display).

If I'm listening to a digital source with the 950 and I turn on the TV, I lose sync (audio) for a few seconds when the TV comes on. Didn't happen with my Adcom pre/pro. This happens every time with the 950. Of course there is a path between the TV and 950 through an Svid cable but I wouldn't expect the 950 to be this sensitive.

Also, when there is no source for the video into the 950, ie. I choose an input that has no Svid or composite source because video takes a different path for DVD playback, the 950's menu will come up fine but the background is not stable. Seems like they could've provided a blue screen for sources that aren't hooked up. Small annoyance probably, but strange.

Cary

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#39678 - 09/27/02 10:41 PM Re: Request for help with TV induced noise
applejelly Offline
Gunslinger

Registered: 12/20/01
Posts: 116
Loc: Syracuse, NY
The buzz is almost completely induced by the TV being on. With absolutely nothing attached to the 950 and only IC's between the 950 and my amp, the buzz is there, even with the 950 powered off. My best IC's, which are RG-59 shielded Belden and only 2' long, did the best at keeping the buzz out. The 6' Rat Shack Audio IC's are grabbing a bunch of buzz. By moving the IC's around behind the entertainment center, I can somewhat very the loudness of the buzz.

I don't have enough good & short IC's to totally eliminate the buzz, but it is now only somewhat noticeable from the listening position.

Then when I turn on the 950, the hiss overlays the buzz. I am certain the buzz is 90% the TV (the rest might be ground loop hum or something else, but not the 950). When I get behind the TV to connect wires, the TV itself is making a buzzing racket. The transformer in my powered sub hums a tad too, so I wonder if dirty AC is making the TV act up. I tried turning off eveything else on the house circuit and got no change in the buzz. It is all about the TV being on and the buzz being picked up by the IC's. Anyone else had anything like this?

I may try totally rearranging my entertainment center to get the IC's further away from the TV, but I am afraid I will do all that work for nothing.

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#39679 - 09/28/02 03:53 AM Re: Request for help with TV induced noise
Kevin C Brown Offline
Desperado

Registered: 12/11/01
Posts: 1054
Loc: Santa Clara, CA
AJ- I know there are isolators for say a cable line to stop ground loops (sounds like you have one already), but anyone know if there's anything you can put on (or *around*) an interconnect? I've seen chokes and stuff, but I don't know if that would do it. www.mcmelectronics.com has them. (But not the easiest site to search through.) www.partsexpress.com might have them too.

Me thinks that this is just another example of the 950's sensitivity to the environment.

I'd be curious if someone dropped a copper plate in the bottom or on top of the chassis, if that would help any...


[This message has been edited by Kevin C Brown (edited September 28, 2002).]
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