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Topic: balanced ground loops isolator

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hi peeps, trying to improve my signal quality on my out-gear (amp, eq, etc) and seeing as I'm now using quality balanced xlr's everywhere the weak link in the chain now becomes the naff piece of plastic with the cheap phonos on the end..or the ground loop isolator to be more precise.

My amp has a ground lift operation on it so was wondering if I even need to use this isolator anymore..?
back to the point, is there a better isolator on the market, preferably balanced? or do I have to make do with this cheesy little contraption lol
 
Posted Fri 07 Jan 11 @ 8:08 pm
Hi mate
If all of your connections are balanced you should not need the ground loop isolator. If you do get any hum from the amp you can use the ground lift switch or disconect the braided screen conection (PIN 1 on the XLR plug) at one end of each XLR cable feeding your amp (You can do this by de-soldering the connection inside the plug and insulating it). It is common practice to do this at the amp end of the cable.

I assume you are using the isolator between the controler/soundcard and the mixer. As long as you use short, good quality phono cables for this conection and take care with your mains wiring you should not have any problems.

Daz
 
Ok, I'm NOT recomending this to others, but after buying quality equiptment and wires and cables, and having a hum, i figured I would try and figure out wher it came from, the concusion I came to is it was being generated from the laptop itself and was coming from the4 power cords ground prong, what I did was wrap the 3rd prong with electrical tape and reinsert it into the power outlet efectivly eliminating the ground fault circut, now like I said I'm not recomending it but it deid work and has never sounded better.
 
Without wishing to cause offence.

Don't ever dissable the electical safety earth on any piece of equipment! It is the wrong way to go about hum problems and can be very dangerous.

I am aware that laptop power supplies can be a source of hum/ground loop problems but the correct way to avoid this is to us an isolating transformer (Ground loop isolator). If you want to improve the quality over some of the cheaper "plastic lumps on a cable" then look at using a pair of high quality isolating transformers. these are available from most studio equipment suppliers. You can also look at purchacing an after market power supply which is double insulated and therefore requires no mains safety earth/ground.

You are quite correct in not recomending this but IMHO it would be a better bet not to mention it AT ALL. Someone will try it and think they have solved their problem but the truth it it could kill someone. Not going to debate this with anyone, it is simply not safe so don't do it.

Daz
 
Dazmax wrote :
Don't ever dissable the electical safety earth on any piece of equipment! It is the wrong way to go about hum problems and can be very dangerous.

I am aware that laptop power supplies can be a source of hum/ground loop problems but the correct way to avoid this is to us an isolating transformer (Ground loop isolator). If you want to improve the quality over some of the cheaper "plastic lumps on a cable" then look at using a pair of high quality isolating transformers. these are available from most studio equipment suppliers. You can also look at purchacing an after market power supply which is double insulated and therefore requires no mains safety earth/ground.



Totally, 100%, positively, in the most absolute verbiage possible AGREE!!! Electricity is nothing to play with, or to take lightly! One, just one amp, or volt, crossing your body when your heart is in between rhythms can KILL YOU!!!! Do not ever cut, or tape, the grounding plug from any device. Use a Ground Loop isolator, or something like this....
 
Usually of your using a laptop and powered speakers , you can sometimes get a hum sound . Best thing to do is to but a Hum-x Plug your laptop adapter into this and the hum will go away, price for the hum-x is $100.00 money well spent .
 
Couple of points...

1) You could use a DI (Direct Injection, Direct Input, choose your terminology) box, such as the Behringer DI-100, etc. These have GLI's in and convert from unbalanced RCA or Jack to balanced XLR or Jack, depending on make and model.

2) If you are in the UK and are using your kit professionally, then you should have all your kit PAT (Portable Appliance Testing) Tested and ANY modifications to the earth will invalidate your PAT test's and expose you to liable action if there is ever a problem - oh and will invalidate your Public Liability Insurance.
 
Dazmax wrote :

I assume you are using the isolator between the controler/soundcard and the mixer. As long as you use short, good quality phono cables for this conection and take care with your mains wiring you should not have any problems.Daz


yeh, using the isolator between the dj io and out-gear.

the numarks ok but the outputs are bog standard, even thinking about other options now as the first link in the output stage (usb) I'm also sceptical about in sound quality terms. not being a jobs-worth but maybe trying to squeeze a little more quality out of the initial signal seeing as I'm paying a fair price for my amp, eq, leads etc.

I dont suppose theres any such thing as a 'balanced' usb output is there ? cheez this shizzles gettin deep lol

my sound quality isn't too bad as it is for now, maybe if it ain't broke then don't fix it eh !

that Behringer gadget looks pretty cool, price range is fair too

I'm hoping the ground lift switch on the amp will deter any hum when I do my next sound check..keep ya posted on that one, cheers people !
 
The only thing you can do with the USB side is to use a good quality, short cable.

There are sound cards that provide a Balanced output directly bt they are more expensive and in many cases may have more than you want in the way of ins and outs.

If you are looking at using DI boxes to provide isolation then avoid the active type units. A simple passive transformer isolated type is what your after here. Check with the manufacturer to ensure the DI box you choose is actualy Transformer isolated and not of the electronic, servo-balanced type, as many of the electronic type do not provide electrical isolation.

Daz
 
Dubcupboard,

I had read this thread back in January and had to agree with you, there I am trying to get a decent system together and have got this crappy ground loop isolator in the chain.

Well last week I came across the solution:

http://www.artproaudio.com/products.asp?type=90&cat=13&id=106

they sell them at Thomann.de for €50 and the company also makes some tip top doo-dads for the studio/Musician/DJ. I havnt tried one yet but will be getting one in the next month or so.

Will report back then.

John(Graham)
 
Perfect bit of kit.

I think I will be adding a couple of these to my "I'v got an earth loop, get me out of it kit".

Thanks for posting that up Graomi.

Daz
 
 


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