My Gear Electrocutes Me.

[Geoff_T]

Originally Posted by DarkEcho

I made a manual ground cable and touched it to chassis screws on all of my gear, but the noise never changed..

its just a small 18gauge piece of wire with a round connector crimped onto the end that I slid over the ground pin on the surge protector going into the wall.

Did I do something wrong?

Hi

I don't follow what you've done.

One end of the cable needs a crimped connector and then is attached (somehow) to the frame of the computer. The other end goes to a good ground.

Don't assume that screws you touch are ground... check everything with your meter (set to resistance!) with one lead on the power cord ground pin and t'other to the screws you want to connect to.

I'd be tempted to take the surge protector out of the circuit....

[hduncan]

I re-measured like you said for resistance, this time I got a reading of 0.65 between the AC Cord's ground prong and a screw attached to the laptop.

to the post above, I crimped an "O"connector to a wire, then I slid it over the grounded pin on the surge protectors cord going into the wall, then I took the other end and touched it to metalframing of various gear.

[Geoff_T]

Originally Posted by DarkEcho

I re-measured like you said for resistance, this time I got a reading of 0.65 between the AC Cord's ground prong and a screw attached to the laptop.

to the post above, I crimped an "O"connector to a wire, then I slid it over the grounded pin on the surge protectors cord going into the wall, then I took the other end and touched it to metalframing of various gear.

Hi

At best, all we are doing is "hamming" this procedure. It's hard if one isn't there to see what's going on and even this grounding is suspect.

I don't know how good a connection to ground you are getting at that outlet... a ring terminal around the plug pin is only contacting via its edge... it's not like a screwed down, solid connection.

I don't know if you have a bunch of studios near you that could loan you the services of a qualified tech. As David intimated, a regular electrician is going to be lost with this sort of problem... you need a proper tech, with credentials you can take to the bank, to see what's going on.

There's always a solution but unless someone is there with a scope, decent meter (yours is a little ancient) and the eyes to see what you may be missing and aren't telling us as a result... we are just going around in circles. If it were easy, it would have been resolved by the early pages!

I don't know what more I can offer by remote control...

[hduncan]

Yes, understood Geoff. I appreciate all of the service and advice you and David and everyone have provided thus far. I was fearing that the day would come when this thread would close without an answer. But I can't expect all of you to keep checking this dead end thread haha

I will contact studios to look for a tech. Until then, I will continue my minor troubleshooting ideas, or I will simply get balanced cables and forget about the whole thing..

It just bugs me that there is something "wrong" in my system.

I'll definately revive this thread when I find out the problem! I'm going to continue posting my progress incase anyone is curious- but please don't feel obligated to reply =) you've all done quite a lot for me already!!! Thanks everyone!


wish me luck.

[hduncan]

It appears as though this is a common problem with MacBook Pro users when using the two prong power connector. I looked at the AC Cord accessory that comes with the laptop with a grounded connection, and the third prong does indeed seem to be there for a reason and I havent experienced a shock since using it. So if you were having shock trouble as well, try the 3rd prong, and if that doesnt work, use a circuit tester to make sure the socket you plug it into has a functional ground.

[Geoff_T]

Originally Posted by DarkEcho

wish me luck.

Good Luck!

[hduncan]

I just tested the duet and HDD out of the loop by plugging one speaker in via the headphne jack and the flatpanel in via DVI (nothing else plugged into laptop except power). Still got noise
so I'm going to take the laptop and one of my monitors into work tomorrow and try to recreate the noise in a new environment geographcally.

[hduncan]

I brought my laptop and one of my speakers with me to work for a little test today. (Mostly to get it into a different environment and see if the noise still happens)

Components:
(1) MacBook Pro
(1) KRK V6 Monitor
(1) Dell Flatscreen (not the same one I've been using at home)
(1) USB cable
(1) 1/4" unbalanced instrument cable
(1) 1/4"-1/8" adapter

A.) I plug the speaker into my MacBook Pro's headphone jack via its 1/4" unbalanced instrument cable into a 1/8" adapter.

B.) I then connect an LCD Flatpanel to my MacBook Pro via a USB cable (allows me to use the USB hub built into the screen)

C.) Then I plug the speaker and screen into the same power strip.

So, I have two devices plugged into the same power strip, and then both of those devices connect to my computer through their respective cable.

I get the same noise I get at home (This rules out the possibility of the noise being interference by any equipment at my house). When I unplug the USB cable, the noise goes away. Silence.

D.) I work in an IT room, so I decided to swap out the MacBook Pro for a Dell D600 sitting across the room.

There is some hiss when I plug the speaker into the Dell's headphone jack, but when I plug/unplug the USB cable into the Dell, the noise doesn't change. This leads me to believe that the Dell simply has a noisy headphone jack, and that the problem in my system is the MacBook Pro!

I did this test with several other laptops (Dell, Gateway, Toshiba, MacBook) just to be sure. interestingly, I found that a regular MacBook has the same issue. I wonder if there is something going on with their internal designs. The MacBook and MacBook pro are similar ages (mid 2007). I was thinking that the MacBook Pro's aluminum case might be an antenna for EMI or something, but the regular MacBook, which also exhibits the same noise, has a normal plastic body.

Very interesting. Not sure what to do about this.

[Geoff_T]

Hi

The whole deal with your set up pointed towards issues with the Mac... but I don't know anything about Macs because I've used PC's all my life. We do have Macs in our studio for PTHD and another in our demo rack for our PTLE set up. Both are G series desktops, not laptops, and neither give us a shred of a problem in a pro studio environment.

You have a Mac laptop and all this grief!

What can one say? Moan to Mac and buy a desk top?

[Geoff_T]

PS A ungrounded metal frame could very much be an antenna... you have to watch this in pc tracks so as to not produce rings of track that can induce either EMF or RFI fields.

It's a minefield if you don't cover all the aspects!

[hduncan]

I am trying out different peripherals to see which types of things cause the MacBook Pro to make noise.

Tests:
Projector connected via USB with 2pin AC cord, No Noise.
HP DVD Burner connected via USB with 2pin AC Cord, No Noise.
Maxtor External HDD connected via USB with 2pin AC cord, No Noise.
Lacie External CD-ROM Burner via USB with 3pin AC cord, NOISE!
Dell CRT monitor connected via VGA-DVI with 3pin AC cord, NOISE!
Backup UPS connected via USB with 3pin AC cord, NOISE!


So I believe that the rule here is that, Anything that has a 3pin AC cord, that is attached to my MacBook Pro, will cause my speaker to make noise.

Just for the hell of it, I connected a desktop to my MacBook Pro by touching an RCA cable to a chassis screw on each computer, NOISE!

[Geoff_T]

Hi

It's very difficult to keep up with you because of some half stated facts...

When you used the Dell, Gateway, Toshiba, etc. laptops, did they run all the functions you need correctly and minus the noise?

Anyway... I'd still use the laptop as a boat anchor and get a G series desktop!

How have other folk got around this?

[hduncan]

Hey Geoff,

I'm not sure what you are asking?

I have about 6 different laptops here including my MacBook Pro, I sat them all, one by one, on the desk and plugged in the screens USB cable and the speaker into the headphone jack and with every laptop, the USB cable to the screen being unplugged or plugged in made no difference in the speaker output.

Some of the laptops had inherently noisy headphone jacks but the noise wasnt "THE" noise I've been dealing with, and it didnt change when the screen was plugged in via USB or unplugged.

Only the MacBook Pro and the MacBook exhibited this awful behavior.

I am strongly considering going to the macstore and getting a Mac Pro.

P.S. Every laptop was running on battery for every test.

[Geoff_T]

Originally Posted by DarkEcho

Hey Geoff,

I'm not sure what you are asking?

I have about 6 different laptops here including my MacBook Pro, I sat them all, one by one, on the desk and plugged in the screens USB cable and the speaker into the headphone jack and with every laptop, the USB cable to the screen being unplugged or plugged in made no difference in the speaker output.

Some of the laptops had inherently noisy headphone jacks but the noise wasnt "THE" noise I've been dealing with, and it didnt change when the screen was plugged in via USB or unplugged.

Only the MacBook Pro and the MacBook exhibited this awful behavior.

I am strongly considering going to the macstore and getting a Mac Pro.

P.S. Every laptop was running on battery for every test.

Hi

Well I'm out of my depth with minimal Mac experience... I use a HP desktop at work with a 19" LCD and a Toshiba laptop at home. I don't do much audio on either other than listen to stored music (not mp3) or watch Youtube!

It seems that you may have found the Macbook's Achille's heel and the desk top version is your savour... but then, what do I know?

I've never wanted to own an IPod because I can't stand MP3

I hope the computer resolves your issue... it's a big expense if it doesn't but, as I said, we have three here with no issues!

[hduncan]

I have created an easy to replicate setup for anyone else with a MacBook Pro to test, I am starting a new thread about this, as this thread has wandered off from the original purpose. I'd like to see if other MBP users can recreate this issue or if I am unique in this problem..

I have a feeling this may be linked to the Firewire Board issue that the recent MBPs have been experiencing.

The noise is louder when the USB cable is plugged into the right USB port versus the Left, which I also find interesting..

If you want to follow this issue, please follow the link below:
Possible MacBook Pro Defect: Noise in Monitors

THANKS!