Any Apple wizards here to help???

**Superfreak** · 02-28-2013, 03:16 PM

Recently i have been hearing a buzzing/humming noise coming out of my studio monitors, which are connected to a USB audio interface i have, thats connected then to my MBP via USB. I haven't ever heard this before but then i have only just started using my interface recently.

i think my MBP battery is on its way out, someone told me to check coconutbattery and it apparently showed that my batter is 4 years old and only has 65% health or something? Plus my macbook turns off randomly as if there was no battery left, when there IS loads of battery left.

I have tried another charger (my dads replacement macbook charger) and still got the humming noise out my speakers... I tried headphones into my macb, and i could hear a kind of static noise, but when i touched the macbooks housing the noise stopped, if i help my finger on the macbook, like on the case it stopped, soon as i let go it carried on...

Can any help me with this please? What do I need to do? Can you tell me to do some tests or something to maybe help you get a better understanding...

ask any questions and ill help to answer you
Thanks

EDIT: when I remove charger there is no buzzing noise, so maybe a problem with the charger port? Because I've tried two chargers!

**Ed Paris** · 02-28-2013, 03:39 PM

the problem is the electric circuit. try hooking up your monitors and macbook to 2 different circuits. this should solve the problem.

**mdcdesign** · 02-28-2013, 09:01 PM

There's a REALLY simple cure to this, which most people don't even realise.

It's your USB cable. You need one with double ferrite chokes on them, which are a PITA to find; DJTechTools actually sells one in their store, which I've got 3 of. Quite expensive for USB cables (by eBay standards), but it WILL solve your problem.

The other alternative is just trawl through eBay looking for one with double ferrite chokes.

THIS is what you want, just not 20 feet long like this one lol.

In fact, this is EXACTLY what you want, and it's only 99p.
http://www.ebay.co.uk/itm/USB-Cable-...item4d09c4a76a

Enjoy!

**vanaema78** · 03-01-2013, 11:11 AM

It's a ground loop and there are many different fixes for that. Google.

**Superfreak** · 03-01-2013, 08:21 PM

Okay, I tried my MacBook charger on another plug socket, but not enough space to plug both speakers in and move the interface etc, so I just plugged my headphones in, and I still got a very slight humming noise, but it stopped when I put my finger on my MacBook :S

Strange.. I tried my dads MacBook Pro replacement charger too, and it made a humming noise as well..

@mdcdesign - Hm, my charger isn't USB tho! I got the humming noise even when the monitors wernt connected (I plugge sheaf phones into MacBook)

I also can't change the audio interface USB cable as the interface end is like built into it.

**mdcdesign** · 03-01-2013, 08:31 PM

Originally Posted by Superfreak

Okay, I tried my MacBook charger on another plug socket, but not enough space to plug both speakers in and move the interface etc, so I just plugged my headphones in, and I still got a very slight humming noise, but it stopped when I put my finger on my MacBook :S

Strange.. I tried my dads MacBook Pro replacement charger too, and it made a humming noise as well..

@mdcdesign - Hm, my charger isn't USB tho! I got the humming noise even when the monitors wernt connected (I plugge sheaf phones into MacBook)

I also can't change the audio interface USB cable as the interface end is like built into it.

Ah you're buggered then. The issue you described is a ground/interference one; you could try buying a ferrite core and fitting it yourself to your USB interface.

**Superfreak** · 03-01-2013, 08:54 PM

Daaamn. So, is this ground loop coming from MBP charger!? Or is it inside my MacBook?

http://en.m.wikipedia.org/wiki/Groun...ity)#section_1 my worries were true, I can actually revive an electric shock from this? I really need to know the problem/whats causing it and whay its affecting so I can try and get it fixed before I blow up my mac or my self :-(

**deevey** · 03-02-2013, 01:41 AM

First thing to do is clean the contacts on the macbook's power socket - may be you have dirty connectors (happens me every so often).

However it sounds like its probably a faulty battery/power circuit which I've seen a few times - if I remember right its a separate board from the logic board and cheap to replace ($30?).

I can actually revive an electric shock from this?

Its only a tiny current - wouldn't be too worried about it to be honest.

**mdcdesign** · 03-02-2013, 02:14 AM

Originally Posted by deevey

First thing to do is clean the contacts on the macbook's power socket - may be you have dirty connectors (happens me every so often).

However it sounds like its probably a faulty battery/power circuit which I've seen a few times - if I remember right its a separate board from the logic board and cheap to replace ($30?).

Its only a tiny current - wouldn't be too worried about it to be honest.

EVERYONE who owns a MBP gets this tbh, but nobody dies from it.

You can tell if a device isn't earthed properly because running your fingertips over it VERY softly creates a sensation kinda like stroking a cat's fur, although it's difficult to explain. Try it with your laptop and you'll see what I mean.

Personally, I experience this on pretty much every metal-cased electrical device, but I'm more sensitive to EM fields than most.