Audio drops out when lights turned on!

altan · 01-11-2004, 08:01 PM

It wasn't clear which forum was most appropriate... Hopefully this one is.

My digit audio drops out for a moment when I switch my lights on or off! It even drops out when the furnace turns on or off!

A little background: I have all sorts of toslink devices connected to my receiver --- DVD player, CD Player, and have never had this problem. These devices are not affected by the lights or the furnace.

However, I recently connected an xbox and it has the problem.

Here is the difference:

- the dvd player and cd player use a toslink (fiber) connection
- the xbox, while it has a toslink (fiber) output, goes into a "toslink to coax" converter and the coax goes into the receiver
- the coax run is much longer than the other devices -- about 25 feet

Any thoughts to solve this problem are much appreciated!

Is this a grounding problem? I don't think the 25 foot run is too long since it works as long as some electrical "situation" isn't happening. Also, it's within the specification of the toslink to coax adaptor.

Thanks in advance.

... Altan

Chu Gai · 01-11-2004, 11:24 PM

Well for starters we don't know if it's due to a glitch coming through the AC lines or an EMI spike coming through the airwaves. If you've got a surge protector lying around somewhere try plugging in the optical/coax converter in and seeing if the built in emi/rfi filtration of the surge protector takes care of matters. If it doesn't let's go from there.

altan · 01-12-2004, 07:38 AM

Thanks for the reply.

I spent a ton of time working on this last night. Using a large industrial strength extension cord I plugged all the devices (receiver, converter, xbox) into the same UPS w/ surge suppression and RFI/EMI reduction. I also disconnected EVERYTHING else (no video cables, no powered subwoofer, etc).

The problem still happens exactly as before.

It also isn't related to the position (route) of my coax because this problem happened before I placed it in the (drop down) ceiling. Specifically, it happened when the coax was simply running on the floor. (Before I realized the relationship between the furnace & the lights, I initially thought the coax run was just beyond specification. So I placed it in the final location and found I could cut off 8 feet. Sadly, this shorter run made no difference).

For what its worth, the problem occurs whether "can" lights in the ceiling are activated or whether fluorescent lights are activated (in addition to when the furnace turns on or off).

Your help is greatly appreciated!

... Altan

Doug_B · 01-12-2004, 11:35 AM

Did you try the toslink-to-coax converter connection on your DVD and CD players?

altan · 01-12-2004, 12:12 PM

Not yet ... My plan tonight was to try some variations.

I'll try what you suggested. Specifically, using it in a situation I already know is working and seeing if the problem happens

Also, I'm going to try getting the xbox closer to the receiver (as a temp situation) and using a short piece of coax and seeing what happens.

If I can find one (not sure if I have one), I could also try connecting a DVD player (or other device) with a built-in coax digital output to my 25 foot coax cable (without the converted, since its not needed her) and see if that problem happens.

I've found other examples of digital audio dropping out when lights are turned on/off, but no solutions!

... Altan

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Jonathan_M · 01-12-2004, 02:28 PM

Out of curiosity (and temporarily disregarding the furnace's influence for a moment) can you examine your TOSLINK cables for any cuts in the sheathing that would let light in?

altan · 01-12-2004, 08:07 PM

I checked out the toslink cable and it looks fine. Interesting thought though.

I just played around with the setup... it's definitely related to the use of coax.

When the xbox is connected via toslink it works fine.

I connected with a short coax and the problem still happened... although it was very hard to make it happen. Appears the longer cable aggrivates the situation.

It might be the toslink to coax converter just isn't that great.

... Altan

Chu Gai · 01-12-2004, 08:40 PM

Recall the kind of coax you're using? Was it something you made or bought and maybe some insight into the shielding.

Dan B · 01-12-2004, 09:09 PM

What converter are you using? I tried the Radio Shack optical to coax converter with my Xbox & it didn't work worth a crap...it dropped out all the time. Might be an Xbox specific thing.

altan · 01-12-2004, 10:25 PM

The coax is quad shield rg6 --- I'm pretty sure its not the problem itself.

Yes... I'm using a radio shack toslink -> coax converter. Interesting you trouble with it!!! Did you have better luck with a different one?

... Altan