Computer-to-receiver hum

Posted by: Eno

Computer-to-receiver hum - 06/08/06 07:10 PM

I have hooked up my computer to my a/v receiver and I get an annoying hum coming from the receiver/speakers. I've connected my Creative Audigy2 soundcard line-1 out port with a 1/8" stereo phone jack to an RCA cable, then a Y-splitter, to my Onkyo TX-DS595 tape ports. I get the hum even if I'm listening to another source (other than the PC/tape). Setting the PC audio out volume to any setting doesn't help. Any ideas?
Posted by: RickF

Re: Computer-to-receiver hum - 06/08/06 07:55 PM

Sounds like some sort of a ground hum problem maybe?
Posted by: SirQuack

Re: Computer-to-receiver hum - 06/08/06 09:15 PM

The sound card and/or your mother board does not have a SPDIF out port? This is what I use from my HTPC I just built, this allows my receiver to do all the decoding. Not sure about using the 1/8" jacks.
Posted by: INANE

Re: Computer-to-receiver hum - 06/08/06 11:57 PM

Definitely a ground loop issue, years ago when I would connect my PCs to the receiver with an analog connection the same thing would happen. I put the PC on a UPS and it seemed to break the ground loop and worked fine. If you did have a digital output you probably wouldn't have the issue (esp with optical interlink).

I am curious thou, whats teh Y cable doing in this senerio?
Posted by: BrenR

Re: Computer-to-receiver hum - 06/09/06 12:10 AM

Quote:

1/8" stereo phone jack to an RCA cable, then a Y-splitter, to my Onkyo TX-DS595 tape ports


I think I'm missing something... why the Y?

Bren R.
Posted by: Eno

Re: Computer-to-receiver hum - 06/09/06 10:56 AM

Thanks for the replies. It does appear to be a ground hum. My PC is on an UPS, so that isn't helping me as it did for Inane. My PC does have an SPDIF out port, but I have my Cambridge Soundworks PC 5.1 speakers connected to it. The Y cable is to split the single RCA cable to the receiver L/R speaker input.
Posted by: BrenR

Re: Computer-to-receiver hum - 06/09/06 12:05 PM

Quote:

The Y cable is to split the single RCA cable to the receiver L/R speaker input.


Oops, think you may have your wires crossed... are you sure you have a stereo 1/8" to RCA cable? It should have two RCAs on the one end and a tip/ring/sleeve 1/8" at the other end... if the ring isn't there, you've got a mono cable.

Bren R.
Posted by: n8wrl

Re: Computer-to-receiver hum - 06/09/06 12:07 PM

Sounds like a 1:1 transformer is in order. We hams connect our computers to radios a lot and this is a very common problem.

-Brian n8wrl
Posted by: Eno

Re: Computer-to-receiver hum - 06/09/06 01:43 PM

I solved my problem and got rid of the hum (and the Y adapter) by buying a ground-loop isolator (aka 1:1 transformer) from RatShack. Now there's no hum at all. Thanks for all your help, folks.

This is why I wanted to hook my PC to my living room receiver: Music Genome Project.
Posted by: INANE

Re: Computer-to-receiver hum - 06/09/06 11:55 PM

Good deal.

Ya those music services are getting popular. I subscribe to Yahoo Music Unlimited and they have a similar system in place where I rate music and it trys to figure out what I might like. Works rather well and its really great as I never know what I want to listen to. Plus discovering new artists and such.
Posted by: a_ok2me

Re: Computer-to-receiver hum - 11/15/06 11:52 PM

I tried the mini to RCA route and I had the same problem. Then, I bought a sound card with a digital output and the db level and sound quality improved dramatically. There's also no hum.

Eventually, I'm going to try an ethernet/optical adapter and bypass the sound card.
Posted by: danmagicman7

Re: Computer-to-receiver hum - 11/16/06 09:40 PM

Here's a question for you, why not just split the SPDIF signal?

Sound quality from the analog of the sound card really doesn't hold a candle to the digital...at least that is what I've found.

I run my receiver off the SPDIF out of the computer.

And, why not give your creative speakers the analog? Or, better yet, amp your creative speakers OFF of your receiver, and just have an SPDIF signal going to the sub for its frequencies...