Axiom Home Page Forums General Discussion Technical Questions Everyone's favorite--it's a ground loop!

OK, I know what's going on. I just don't know how to fix it. I'm trying to hook up my computer (3 prong plug, kinda grounded) to my second receiver (2 prong plug, at least it's plugged into the same outlet as the computer, I think). I get the dreaded buzz/hum thing. My headphone amp (2 prong plug, same outlet as computer) doesn't have the problem, but does pass it to the receiver if I hook it up with a 1/4 plug to 1/8 plug to RCA chain of adapters. Also happens with the KVM+sound thing I've got. If I hook up an iPod to the cable, no hum.

Any thoughts?

Yeah Ken, you're right about the "favorite" bit. I'm pondering and I'm having trouble coming up with a loop if everything else is just grounded through their connections to the grounded(by three prong)computer. Will continue to ponder.

Um, can't you just stand in a bucket of water while you're listening to headphones or something?

Uh huh... I just wanted to listen to music from the computer on the M50s!

Yeah, well, we all want lots of things, Ken. Sleep, food, HDTV, dry pants.

And, apparently, you can only ever have three of the four simultaneously. Dry pants have to lose out some of the time.

Quote:

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If I hook up an iPod to the cable, no hum.

Any thoughts?

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Try singing a few bars and i'll see if i can figure it..oh, i guess i should've read the first part of the post first.
Sorry Ken.

There's an antenna on it. I'll try the direct connect.

Find a cheap sound card with SPDIF.

http://www.newegg.com/Product/Product.aspx?Item=N82E16829130001

$8 does the trick :-)

It's a Mac that I'm using for this one. Also happens with the PC, incidentally.

I guess the only way to upgrade a mac is throw it out and get a new one, eh?

Thbbt... no, there are certainly cards available (I could get something for $30) and this machine has been fairly upgraded. However, since Dan motivated me to get off of my butt and actually try some stuff, I've made an interesting discovery: touching the ground wire to the computer produces a worse hum, even without the RCA cable. Zees ees ve'ry st'ranjeh.

You know, that brings up a really funny college story.

So, we are sitting in my friends dorm room, who has a cheap receiver with a pair of speakers. On the same long desk as the receiver and speakers, my friend Danny was sitting there on his laptop. So my friend Jon is in the room and walks by the receiver and notices a ground hum. Eventually, he breaks out in a wild dance flinging his cell phone (the source in which he thought the ground noise was coming from) near the receiver. He was making arcs in the air spinning around, clutching is cellphone, and swinging it in close proximity to the receiver. The speakers were making a rhythmic ground hum noise that faded in and out in conjunction with his arm flailings.

The receiver was set to "video".

After Jon had had his fun, Danny had a secret to tell. Since the receiver was set to video...it was the connection that Danny used to output sound from his laptop to watch videos and so forth. Danny had been sliding his finger gradually up and down the 1/8" jack to create the ground hum noise. Everyone laughed once he told us his 'secret'.

After that, I experimented touching different metal things with the 1/8th inch jack connector. We eventually had a chain of people who held hands with the last person touching something metal, creating some interesting ground hum noises. It was much fun, but not gay...yea.

Ok, that's my story....sorry it doesn't help, but it does give you something to do if you're bored.

Wow...WOW...I just realized the hilarity of that statement as a standalone statement.

Heh, funny. What a gay old time we are having here.

I had this problem back in June (see this thread). I solved it with a ground loop isolator from Radio Shack .

Thank you! I'll give it a shot.

It works! I.m now rocking my son to sleep with Tool-Aenima.