I can hear TV2's audio through surround sound hooked to TV1

[FantasyChannel]

Last time I picked up a radio station through speakers was on my electronic organ in my home. The only solution lifting the ground on the power plug. I thought I was getting the same thing through my surround sound until I started hearing South Park. It turns out it is TV2 on my 622 somehow getting into TV1's audio lines. My stereo receiver doesn't have optical out (too old) so I am using the RCA jacks. I've disconnected/reconnected cables. Tried different cables, grounded, ungrounded and so far no solution. It seems to be internal within the box. Is this some sort of ground loop going on?

 

[brandonsound]

yes, lifting the ground on the power plug... always safe

how are you getting the signal to TV2?

 

[FantasyChannel]

how are you getting the signal to TV2?

Coax.

 

[Tom Bombadil]

This is a very common problem for line output boxes. Cross-talk noise. Almost always present in an analog output stage.

Not only will it be present between the TV2 and TV1 outputs, but some will be present between the L/R outputs of both.

There is no way to eliminate it, short of going with your optical digital output.

For example, if one had an old stereo receiver and punched an input which had no source and then turned up the volume, you would hear the FM radio output still coming through at a very low volume level.

 

[FantasyChannel]

Ok, time for optical upgrade. Thanks Tom.

This is a very common problem for line output boxes. Cross-talk noise. Almost always present in an analog output stage.

Not only will it be present between the TV2 and TV1 outputs, but some will be present between the L/R outputs of both.

There is no way to eliminate it, short of going with your optical digital output.

For example, if one had an old stereo receiver and punched an input which had no source and then turned up the volume, you would hear the FM radio output still coming through at a very low volume level.

 

[cybertrip]

Also, check your coax on the TV2 output. You may have an RF leak caused by a unshielded center conductor which could get in to your stereo equipment causing you to hear whatever is being transmitted on that line.

 

[FantasyChannel]

Also, check your coax on the TV2 output. You may have an RF leak caused by a unshielded center conductor which could get in to your stereo equipment causing you to hear whatever is being transmitted on that line.

I checked that thinking the same thing. I unhooked the TV2 coax line from the box and it's still there.

 

[cybertrip]

if the components in the receiver are properly shielded you shouldn't have this problem. although good luck getting a replacement because of this issue.

 

[FantasyChannel]

if the components in the receiver are properly shielded you shouldn't have this problem. although good luck getting a replacement because of this issue.

oh it's not worth getting a replacement. I'll just upgrade my stereo receiver so I can use optical.

besides I hate talking to tech support.

 

[hokiecb]

well... if I were an advanced tech support agent with dish, and I had disconnected the tv2 out coax like you did, and reset it a few times, and you still had tv2 audio coming out of tv1, then I'd Send you a new one. Call em, cant hurt. They've replaced plenty of boxes with smaller issues... and if it doesnt work then you've eliminated that as your problem. Free is cheaper than buying a 5.1 surround sound, however that would be a great excuse to get that new sound system.

 

[Tom Bombadil]

if the components in the receiver are properly shielded you shouldn't have this problem. although good luck getting a replacement because of this issue.

The analog output stage of a Dish receiver is pretty low end. Reducing crosstalk to very low levels requires careful design of the IC circuits, isolated circuits, and good shielding. Usually this isn't found in anything less than good amps, preamps, and higher end A/V receivers. I've heard high levels of crosstalk in $1000 A/V receivers.

I'm assuming that the OP is only hearing the sound when TV1 is silent and he has the volume cranked up. If you hear it with the volume levels at low or medium, then you may have a receiver that hasn't been assembled properly.

 

[FantasyChannel]

That is correct that the volume has to be up quite a ways to hear the interference but I don't have it cranked up entirely. I can't hear it at normal levels with other things playing, but I still should just be hearing hiss when turning up the volume. Oddly enough the TV2 audio goes away when I put the receiver in single mode. I could just get another receiver to go where TV2 is. That will give me a good excuse to put HD in the bedroom.

I was originally checking the speakers for distortion trouble I was having and turned the volume up to hear how clean the speakers were. That's how I ran into this whole thing. I thought I was picking up a radio station before discovering it was TV2.

Thanks for all your input.

 

[Tom Bombadil]

When you go into single mode, there is only one audio stream, so they may be shutting down some of the circuits. With both circuits active, you've probably got -50 to -60dB of crosstalk. Turn it up high enough and you'll hear it over the hiss, which should be more like -75dB.

Phonograph stylii usually only had about 30-35dB of channel separation between the L/R channels. It was very easy to hear sound from the right channel in the left speakers.

 

[hemirod1]

I have had Dish Network in my garage since December. When they installed it they couldn't burry the cable because the groud was frozen. the tv in the garage(TV2) hasworked fine, but the TV on the back porch (TV!) plays he sound from the Garage TV. Oh!! They came and burried the cable yesterday....uh!! Does that mean that my cable is broken and needs to be replaced??