What are you using to isolate ground hum noise?

kingaaa

I've got my laptop running into a focusrite saffire interface running into a yamaha powered desk. Now I know all about ground-loop isolators, but have only seen them as a single input/output system. I'm using 6 mono outputs on the saffire, so I'd need something with at least 3 stereo inputs and 3 stereo outputs. Anybody seen such a thing?

madtheory

Just buy 3 stereo boxes? ART make nice ones.

PaulBrewer

If you clip the shields on your 6 Saffire outs at the Yamaha input end that should get rid of it.

A ground hum is caused by 2 (or maybe more!) earths connected at the same time with one ( or maybe more !) with a resistance across which the hum is developed.

So if you snip your shields you'll still be shielded, from the interface end earth, which will still have a complete circuit.

Try it with one and see how you get on - it will work if the problem is indeed an earth loop.

SeanHurley

I believe these are the business:

http://www.ebtechaudio.com/hedes.html

However I have not used one but all reviews have been positive.

PMI

I have everything running through power conditioners as well to eliminate other probs, but follow everything said above

Bluebirdstudios

As PMI said , A power conditioner is a good bet.
Better still a UPS system (on line technology) is getting cheaper and for the power your drawing should be able to pick up something in the €200 - €300. I power the whole studio with 2 very large UPS systems and the sonic benifits are real, plus back up time when power goes.
The equipment specs you read are based on steady power supply filtered and regulated. So your equipment will be happy too!

- Dec

kingaaa

Thanks for all the replies lads, well appreciated. Forgive my ignorance, but what exactly is "clipping shields"?

PaulBrewer

kingaaa wrote: »

Thanks for all the replies lads, well appreciated. Forgive my ignorance, but what exactly is "clipping shields"?

Oh man have you not heard of Clipping Shields ? They're playing the Crawdaddy Stage at Electric Picnic ?


No .... it's the 'earth' connection on the jackplug at the yamaha desk input end.

kingaaa

PaulBrewer wrote: »

Oh man have you not heard of Clipping Shields ? They're playing the Crawdaddy Stage at Electric Picnic ?


No .... it's the 'earth' connection on the jackplug at the yamaha desk input end.

ok, what exactly does this entail?

kingaaa

PaulBrewer wrote: »

If you clip the shields on your 6 Saffire outs at the Yamaha input end that should get rid of it.

A ground hum is caused by 2 (or maybe more!) earths connected at the same time with one ( or maybe more !) with a resistance across which the hum is developed.

So if you snip your shields you'll still be shielded, from the interface end earth, which will still have a complete circuit.

Try it with one and see how you get on - it will work if the problem is indeed an earth loop.

It definitely is an earth loop, when I unplug the power lead from the laptop the noise dissapears

PaulBrewer

Just literally cutting the earth/ shield so it's not connected to the plug.

However , Ive heard of similar problems which aren't earth loop related .
Namely , the laptop powersupply itself is the issue.

In fact that may be more likely as the earth is unlikely to be continued to the laptop itself I.e the powersupply itself might be earthed but not the laptop itself.....

Some machines just aren't designed for serious audio use.

madtheory

PaulBrewer wrote: »

the laptop powersupply itself is the issue.

This is indeed the case.

kingaaa

PaulBrewer wrote: »

Just literally cutting the earth/ shield so it's not connected to the plug.

However , Ive heard of similar problems which aren't earth loop related .
Namely , the laptop powersupply itself is the issue.

In fact that may be more likely as the earth is unlikely to be continued to the laptop itself I.e the powersupply itself might be earthed but not the laptop itself.....

Some machines just aren't designed for serious audio use.

I assumed it was the laptop causing this, it is a common fault with laptops is it not? I would be reluctant to clip anything on the desk seeing as I dont think its the source of the problem. So back to my original question, does anybody know of 1 unit taht will take all my inputs/outputs and get rid of the ground loop hum? If I could avoid getting 3 seperate units it would be better all round I think.

SeanHurley

The Ebtech HE-8 I linked earlier in the thread would seem to do the business for you no?

PaulBrewer

kingaaa wrote: »

I assumed it was the laptop causing this, it is a common fault with laptops is it not? I would be reluctant to clip anything on the desk seeing as I dont think its the source of the problem. So back to my original question, does anybody know of 1 unit taht will take all my inputs/outputs and get rid of the ground loop hum? If I could avoid getting 3 seperate units it would be better all round I think.

The second scenario suggested isn't a ground loop. It's power supply noise. So a solution that would work on a ground problem ( snipping or a box) won't work here.

It's only the cables you'd be cutting not the units themselves.

kingaaa

SeanHurley wrote: »

The Ebtech HE-8 I linked earlier in the thread would seem to do the business for you no?

Sean, believe it or not I missed that!!! Cheers Mate, that looks exactly what Im looking for.

Quiggers

buying a double isolate power supply for your laptop will also do the trick

look for this symbol

the different grounds are caused by the different ways of wiring a transformer in a power supply, centre tapped give a true earth as opposed to a floating earth when a transformer isn't centre tapped,

i also use an art clean box, for when plugging into a house pa system, comercial building are fed 3 phase power and the front of house mixer can be on a different phase to the amp room and the stage/dj booth, quite often a kitchen will take up a phase and the other 2 will be spread thru-out the building. these can cause ground loops but be aware that connecting equipment on different phases can dangerous. so pick a set of sockets
and plug the lot into that. unless you're running a 4K system, then you'll need your own 3phase supply, ye flash geht!

madtheory

So do you use a double isolated PSU and an ART cleanbox?

Venues that have stage and FOH audio gear on different phases are being very silly.

kingaaa

Quiggers wrote: »

buying a double isolate power supply for your laptop will also do the trick

look for this symbol

the different grounds are caused by the different ways of wiring a transformer in a power supply, centre tapped give a true earth as opposed to a floating earth when a transformer isn't centre tapped,

i also use an art clean box, for when plugging into a house pa system, comercial building are fed 3 phase power and the front of house mixer can be on a different phase to the amp room and the stage/dj booth, quite often a kitchen will take up a phase and the other 2 will be spread thru-out the building. these can cause ground loops but be aware that connecting equipment on different phases can dangerous. so pick a set of sockets
and plug the lot into that. unless you're running a 4K system, then you'll need your own 3phase supply, ye flash geht!

Thats interesting, these are obviously a universal-type adaptor or are they brand specific?

Quiggers

its an ieee symbol, internationally known.

i only use the clean box when the amps aren't plugged into the same sockets as me

PMI

thats it 100% you can pick um up in maplin or anywhere they're universal just check voltage etc..