HUM

[Dome]

I have recently hooked up a PC to my HT for music playing purposes. I have been experiencing very loud humming when switched to the input hte PC is on. No other input really hums. The PC as well as the receiver are both plugged into the same surge protector and they are connected via some cheap analog RCA connectors. Would switching to an optical cable help with this hum at all? It is fairly noticable, even at lower volumes, and becomes extreamly obtrusive at higher volumes.

Thanks,

Adam

[DrWho]

try moving the cable that connects the pc with the stereo around...if it's running near any powersources or other highvoltage lines (like a power cord, or the power supply on the pc), then there's a good chance that it's picking up interference.

another thing you might wanna check is that you have everything muted on your soundcard that you aren't using or don't need.

and lastly, just doublecheck that you have the cable plugged into the right hole...sometimes it's hard to see back there and it's easy to miss.

[Rudy81]

Other issues to check are coax connections from antennas, cable providers and satellite. In my case, the satellite coax causes ground loop problems. I was able to isolate it by connecting the coax to the surge suppressor my system is hooked to and then bringing in the source to my system.

Good luck.

[Fish]

If you use optical only that should eliminate any hum from ground issues.If not,you may have a ground problem with other connected equipment.

[Dome]

The hum is present even with the master volume on the PC muted. The RCA cable looks like it may be running parallel to a power cable for a short distance (maybe 9"). I do not know if I will be able to do much about that, other than routing it way out of the way. Is it a safe assumption (to start with anyways) that this may be the cause of my problem?

Thanks,

Adam

[Rudy81]

I would suggest a thorough troubleshooting session. Start by unplugging everything from your system except the speakers. The hum should not be there. Then, connect each piece of gear, one at a time. Be careful and don't connect cables to the receiver/processor with the power on. You could trash your speakers. That should tell you where the problem lies. You will then be able to focus on just the problem and not have to guess as to where the problem is.

I had to do that and was able to figure out that my dish coax was causing a ground loop. The antenna is grounded to a different source than all my other gear.

[DrWho]

to test if that 9" is the cause...simply lift the rca cable or move things around and see if the hum changes based on how you're holding things.

however, rudy's idea of plugging things in one at a time is probably the best way to troubleshoot in this situation. once you find the hum, disconnect everything else and make sure the hum is in fact isolated to that one channel (and not being cause by something else previously plugged in).

btw, are you able to play music from the pc, or do you only get the hum?

[Rudy81]

Other things to try. See if you can have the power cables cross the audio and video cables at a 90 degree angle. If you can't, I have read that seperating them using foam blocks about 1 inch thick will help.

[Dome]

Well, re-routing the cable was going to be a difficult task, so I just decided to get a digital optical cable. This solved the problem. It was a little higher quality cable than the crappy RCA interconnect that was causing hte problem and it also seems to me that the bass is a little more defined and a little tighter, especially for the lower quality source (mp3).

So all is well I guess. However, would somebody mind explaining to me how a 'ground loop' occurs. I had not heard the term until I saw it on the board, I had always just figured it was interference, maybe from all the fans etc in the computer or from power cables.

Thanks,

Adam

[Rudy81]

Dome:

Just run an internet search for "ground loop" and you will find much more information on the subject than you will ever want to know.

[Trey Cannon]

if you have a cable modem, dissconnect it...from the cable

does the hum go away?

The cable tv system is alot of the time the problem.

[burtlively]

GROUND PROBLEMS! every opinion/fact listed above is true. i had a very annoying hum in my system so i:

replaced outlet w/new hospital grade outlet, purchased monster powerbar 1100, unplugged ALL wire and reinstalled, and i STILL hear a hum every now and then which has in EVERY circumstance been traced back to my tv coax. proper grounding has been the biggest pain in my #^$(@&. it seems to endlessly haunt me!