[Gatticus]

I'm not sure if this is the correct forum to post this to but considering the offending device is part of my HTPC and is sound related thought this would be the best forum to go with.

My external Viewsonic N6 TV Tuner is hooked to my LCD Projector and the audio out goes straight to my amp. The audio out of the TV tuner causes a ground loop hum. What do I need to buy to get rid of the hum? Thanks.

 

[Herandu]

If the tuner has an optical output, try it with a DAC. There are however some digital audio formats used by the TV companies that a DAC can't decode.
So one other thing to try is to plug the tuner and amp into the same power rail in your house. One way to do that is to get a mains extension block and plug everything in that. Then plug the block into the mains socket in the wall.

 

[mrarroyo]

The cheapest solution to try would be a cheater plug on the end of the tuner a/c cable. By switching the plug you reverse the polarity and can quickly determine if it helps or not.

 

[Gatticus]

OK, I'll have to look up cheater plug. I have heard too that Radioshack sells ground loop isolators so that may work also. Or is that the same thing?

There is no digital out on this Viewsonic N6.

 

[Jeff E]

Do you have a cable connected? Sometimes a HT hum is due to the cable having a different ground level than your home circuits. Try disconnecting the cable to see whether that is the hum source.

 

[Andrew_WOT]

Quote:

Originally Posted by Gatticus /img/forum/go_quote.gif OK, I'll have to look up cheater plug. I have heard too that Radioshack sells ground loop isolators so that may work also. Or is that the same thing? There is no digital out on this Viewsonic N6.

Two prong adapter (cheater plug) works the best w/o affecting SQ. Don't bother with ground loop isolator, but if you decide to go for one check Xitel product, it's far better than RadioShack's. (http://www.xitel.com/USA/prod_gli.htm

 

[Gatticus]

The plug is already only two prong so there is no point in a cheater plug. I just realized I already have a cheater plug anyway as one came with my LCD Projector, it even has a ground wire hanging off it if I want to connect it to a ground connector. I think I need the ground loop isolator. For now I only connect the tuner too my amp when I want to use the tuner to watch TV on the projector. I can only notice the hum when I turn the amp volume up loud but I want it gone one way or another so I don't have to keep reconnecting the tuner. Thanks for the link to the isolator but I am in Canada. We don't even have Radioshack up here anymore. All the Ratshacks are now called The Source by Circuit City but they are pretty much the same as Ratshack was so I expect they have the isolators still.

 

[Gatticus]

Quote:

Originally Posted by Jeff E /img/forum/go_quote.gif Do you have a cable connected? Sometimes a HT hum is due to the cable having a different ground level than your home circuits. Try disconnecting the cable to see whether that is the hum source.

Thanks, but I already know it is the hum source. I've known this device causes a hum for a long time and I put it away for a long time but I need to use it again since I got the LCD Projector.

 

[Logistics]

So... you run the video out of the tuner to the projector, but the audio out of the tuner straight to the amp. Did you try running the audio into the projector and then out to the amp?

 

[Gatticus]

Projector has no audio in or out. I really think the ground loop isolator will fix.

 

[Gatticus]

Here's my choice of ground loop isolators. Which do you think is the better one?

http://www.thesourcecc.com/estore/Se...ator&pagenum=0

The top one I can buy at the store tomorrow but the bottom one is a web order only.

 

[lini]

Gatticus: Does the hum disappear, when you remove the antenna connection from the tv tuner?

Greetings from Munich!

Manfred / lini

 

[Gatticus]

Just tested for that and no it doesn't. It's something internal in the audio out of the Viewsonic N6 that is causing it. Viewsonic screwed up somewhere and I should have returned it but I let the warranty expire before I got around to contacting them about it. I did complain to them via email and of course they tried to blame it on my soundcard at the time. But now it is not even connected to a soundcard so it is definitely the N6 that is causing it. I'll try the ground loop isolator.

 

[bigshot]

If your electrical wiring is fairly recent, connect a wire to the screw in the middle of the outlet faceplate. That should be well grounded. Touch the other end of the wire to a bare metal spot of the chassis of your tuner. If that cancels out the hum, then attach the wire to it.

See ya
Steve

 

[ozz]

i noticed you said when its run through the tuner if the cable/sat or ota
has a separate ground rod this will set up a ground loop all grounds should
go to the ground rod attached to your breaker box.