Faint hum from speakers

[Chris]

I have a couple of RCF Art712-A speakers and have recently noticed that even when no tracks are playing, there's a faint hum from both speakers. I've had the speakers for about a year and the hum may have been occurring since the purchase. What's the solution please?

[super-hero]

If it's only a really faint hum when you have the speaker volumes turned up, then I probably wouldn't worry about it.

Try unplugging everything from the speakers to see if the hum is still there. If not, plug things back in, until you find what is causing it.

[Sapphire Disco]

Very interesting smelly speakers never come across that before do you think maybe someone could have slipped a stale sausage roll in through the front grills whilst you were not looking at a gig :D

[Chris]

If it's only a really faint hum when you have the speaker volumes turned up, then I probably wouldn't worry about it.

Try unplugging everything from the speakers to see if the hum is still there. If not, plug things back in, until you find what is causing it.
Will try that - am in the middle of moving house, so can't do it at the moment though. Any other suggestions, just in case.

[Excalibur]

Try unplugging everything from the speakers to see if the hum is still there. If not, plug things back in, until you find what is causing it.

Excellent starting point. Check also whether there's a ground lift switch on the back of them. If there is, change the position of one, and see whether that makes things better or worse on that cab. With actives, you can compare both ways simultaneously.

Never alter the position of the switch with the cabs turned on.

[Chris]

Excellent starting point. Check also whether there's a ground lift switch on the back of them. If there is, change the position of one, and see whether that makes things better or worse on that cab. With actives, you can compare both ways simultaneously.

Never alter the position of the switch with the cabs turned on.
Thanks for that, truthfully, I can't remember seeing a ground lift switch on the 712-A's ? I'll have a look when I get everything out of box's in about 2 weeks.

For the sake of a few pounds, I'll also buy a ground isolator, what's a good make and model of ground isolator please?

[Chris]

Thanks for that, truthfully, I can't remember seeing a ground lift switch on the 712-A's ? I'll have a look when I get everything out of box's in about 2 weeks.
Wasn't one there.



For the sake of a few pounds, I'll also buy a ground isolator, what's a good make and model of ground isolator please?
Anyone know?

[DJ Jules]

For the sake of a few pounds, I'll also buy a ground isolator, what's a good make and model of ground isolator please?

Yup, there's no ground lift switch on the RCF ART series. There's not really a lot between ground loop isolators. They're basically a couple of coils of wire on a ferrite core so you can't really go wrong.... The only difference between them will be the quality of the connectors. One of mine came from eBay and the other from Maplins :zip: Both have been working fine for years.

Once you've worked out if the speakers or the source causing it, if it's not the speakers it's also worth looking for open channels on your mixer that have no connection (e.g. channels faded up, but with no equipment connected to them) as pre-amps without a source can generate quite a bit of hum.

Hope that helps?

Julian

[Chris]

Thanks Julian. Where does it fix onto?

[Excalibur]

Thanks Julian. Where does it fix onto?

Just a word of caution. Ground loop isolators tend to have a male and a female RCA (Phono ) plug and socket. This means unbalanced connections, and I'd hazard a guess that you're using XLRs at each end, which means some form of adaptor somewhere. Problem is, if you put the GLI next to the mixer, you'll have a long ( presumably ) unbalanced cable, which is more prone to picking up the problem you're trying to cure, hum. Hang 'em at the speaker end, and I guarantee they'll cause problems, cos they don't like having the cables moved a lot.I used these (http://cpc.farnell.com/unbranded/a-1095/ground-loop-isolator/dp/AV12774) and built them into the case, so they were never disurbed.
Damned if you do, and damned if you don't. I'm sorry I haven't been a little ray of sunshine over this, but I'll have another think, and see what I can come up with.

[SamV]

I have loads of ART DTIs for this purpose :) Work brilliantly.

[Excalibur]

I have loads of ART DTIs for this purpose :) Work brilliantly.

Care to elucidate? Give a link perhaps? I've not heard of them.

[DJ Jules]

Care to elucidate? Give a link perhaps? I've not heard of them.

I think this is what (http://artproaudio.com/artcessories/audio_solutions/product/dti/) he's referring to - which would be the holy grail of high quality ground loop isolators with balanced inputs and outputs as well as Jack and Phono connectios :D Sells for about £40.00 by the looks.

I'll add that on my Xmas list :D

Julian

[Excalibur]

I think this is what (http://artproaudio.com/artcessories/audio_solutions/product/dti/) he's referring to - I'll add that on my Xmas list :D

Julian
Father Christmas isn't usually so profligate round here. :( Lesser mortals use these (http://www.behringer.com/EN/Products/DI20.aspx) Half the price.

[SamV]

That Art Dti is also dual channel and sounds as clean as they come. I highly recommend giving one a go.