[AudioNoob]

I have a problem, I hear a constant hiss in addition to the local radio from my speakers when they aren't plugged into anything apart from power. I found that if I stash the power cable under books and other things, the hiss noticeably decreases which, lead me to believe that I have a grounding problem, as the hiss decreases when I hold the cables also.

Any fix?

 

[scootermafia]

That's a ground loop. Lots of threads on this one.

 

[Steve Eddy]

What kind of speakers do you have? I assume they're powered speakers?

se

 

[Steve Eddy]

Quote:

Originally Posted by scootermafia /img/forum/go_quote.gif That's a ground loop. Lots of threads on this one.

Ground loops don't typically manifest themselves as hiss, but rather hum and buzz. Sounds more like he's picking up some noise and interference due to not having anything plugged into the input of his speakers.

se

 

[AudioNoob]

No I get the noise when it's plugged in also, ruins pauses in piano/classical.
I thought a ground loop happened when it had a ground external to the houses.

I've got a swans m10 small bookshelves powered by a sub, wouldn't there need to be third prong on the plug to create a ground loop? This is just two prong

 

[AudioNoob]

it is more a hum and buzz + local radio.

I could get an isolator from radioshack and see what happens

 

[Steve Eddy]

Quote:

Originally Posted by AudioNoob /img/forum/go_quote.gif No I get the noise when it's plugged in also, ruins pauses in piano/classical. I thought a ground loop happened when it had a ground external to the houses. I've got a swans m10 small bookshelves powered by a sub, wouldn't there need to be third prong on the plug to create a ground loop? This is just two prong

Ok, so you're getting the problem both when you have the M10 connected to a signal source and when it's not, correct?

Also, the sub only uses a two prong plug.

If that's the case, then I'm not seeing any ground loop issue here, particularly with regard to the radio interference.

Has this been a problem since you bought the M10, or is it something that's only recently developed?

se

 

[AudioNoob]

yes I get noise either way and it's been this way since I bought the speakers(used), the previous user said he didn't have such a problem.

Volume vise I'm not nitpicking, sometimes you can listen to the song on the radio and understand the lyrics.

Is there any modifications I can do, perhaps install some capacitors in the signal path?

And if It's not a ground problem, why would moving the speaker cables change the amount of radio that I get? I feel like the ground from the speakers are feeding back into the input somehow.

 

[Armaegis]

Wait... are you saying you're hearing the radio when you don't even have the radio turned on? Because that'd be some massive interference you're getting.

Maybe just try a ground loop isolator? It's a $20 RCA cable from radio shack with a knobbly thing in the middle. It gets rid of most ground loops and electronic buzz from my computer.

 

[AudioNoob]

Yes, I hear the radio regardless of what I have / not have plugged in.

 

[Armaegis]

Are your cables extra long and sitting in a coil on the floor? My first check would be to shorten the cables and make sure they aren't looping (and if they must, try the over/under method for wrapping). Shielded cables would also be a good investment.

 

[AudioNoob]

coiling them actually reduces noise for me, my cables aren't that long either.

 

[Steve Eddy]

Quote:

Originally Posted by AudioNoob /img/forum/go_quote.gif coiling them actually reduces noise for me, my cables aren't that long either.

What if you unplug the cables completely? I assume that the sub has female RCAs on it for source input?

se

 

[AudioNoob]

right now, it reduces it to a hum/buzz with faint radio, If I twist the cables around my interconnect, it gets faint but still noticeable. If I move my hands within 10 inches of the speaker cables the hum gets louder, ultimately resolving some radio signal when I hold them.

My interconnected is shielded but the speaker cables are not, it's the monoprice one that's thick and rigid.

IF I place the speakers farther apart, the buzz gets louder leading me to believe that they are acting as an antenna and feeding back into the amp, perhaps hinting to a ground crossover between the input and the output?

ok one more thing, if I just plug in speakers and no input now, there is loud buzz and radio, but when I take the interconnect(not connected to anything, not the amp, nor an input) and place one end a couple inches away from the speaker cables, the buzz is reduced to a hum. Best is if I stash it under books and stuff along with the slack from the power extension and the amps power cable.

And now if I connect the interconnect to the amp and hold the other end, buzz gets really loud, if I take the interconnect and put it adjacent to the power plug where the extension in plugged, it gets fainter

 

[Steve Eddy]

Well, at this point, I'm still not seeing it as any sort of grounding issue, but rather either poor design or more likely, a problem in the amplifier.

What happens when you give the subwoofer a good whack? Nothing to cause any damage, but a smack with the flat of your hand?

Does it cause any sort of crackling or other noise? Does it effect the amount of hum and buzz?

se