[Jonathan_H]

Hi, I'm using a 2008 model Mac Pro and hear a very high pitched whine through my Bose QC2 headphones when connected to the front audio jack. There is no whine when I have it connected to my iPhone or the rear audio jack (yet I usually have speakers connected there), however. Is the front audio jack on the Mac Pro just poorly shielded from the electromagnetic interference or is there some update I can get to fix this?

Thanks!

[ebuddy]

Originally Posted by Jonathan_H 

Hi, I'm using a 2008 model Mac Pro and hear a very high pitched whine through my Bose QC2 headphones when connected to the front audio jack. There is no whine when I have it connected to my iPhone or the rear audio jack (yet I usually have speakers connected there), however. Is the front audio jack on the Mac Pro just poorly shielded from the electromagnetic interference or is there some update I can get to fix this?

Thanks!

Try unplugging the speakers you've got connected to the back of the machine, plug the headphones into the front of the machine. Does it still whine? I ask because you're unplugging the speakers from the back of the machine to test your headphones in back. Just curious. If you don't get the whine, the speakers (and any related amplification) might be causing the issue.

[Jonathan_H]

Interesting, I unplugged the speakers and there is definitely a reduction (its still there slightly...) in the whining sound. I'll give it a few days and report back!

Thanks ebuddy!

[ebuddy]

No problem Jonathan_H. You may also consider the outlets you've got things plugged into and the lighting. I'm a big fan of halogen spotlighting-dimmed so I've had to track down strange noises.

[Jonathan_H]

Hmm. The sound is back after about a day... I also tried with iPhone headphones connected to the computer and I still got the sound.

[cgc]

Does the sound diminish or change when you touch the case of your Mac?

[ebuddy]

I'd unplug all peripherals including those other speakers if not already and make entirely sure it's narrowed down to the machine. This includes turning on and off lighting in that room while listening.

If your machine is plugged directly into the wall, use a surge protector. If it's already plugged into a surge protector, move to another outlet and/or use a different surge protector. Try plugging your headphones into the Mac Pro's front 1/8" port and gently twist (not side-to-side, but carefully rolling) the cord end inside the port, any difference in contact or interference? If yes, blow it out. Still no luck? You might have an issue with the 1/8" port. I'm also wondering...

Is the whining affected by any tasks you're doing on your computer; opening/closing windows, running apps, etc...? If yes, it's likely above me. I did have a dual 2GHz G5 that required CHUD tools for managing the processors to silence my noises, but those noises were more like chirps and beeps. I have a 2 x 2.66 GHz Mac Pro now and no noises, but those are running through an audio-interface, among other things.

[Doofy]

I'm confused.

Isn't the 1/8th inch socket on the back of the Mac Pro a line level socket while the one on the front is a headphone socket? Thus the front doesn't actually have a problem in itself - it's amplified as intended, while the unamplified rear is masking the real problem with much less gain than is normal.

I'm gonna go with some kind of lighting or mains problem. Unless the very high pitched whine only happens when iTunes is showing the words "Justin Timberlake" in the display.

[Jonathan_H]

I just tried with all peripherals unplugged, different outlets, lights on/off, etc...all of what ebuddy mentioned. It seems that its something isolated to the front audio jack, as the rear one works fine.

Perhaps doofy is correct with the difference in gain...its only very slightly noticeable in the rear audio jack, but only if you're really listening closely for it. I think I might just keep the headphones connected to the rear, and the speakers up front (since the noise isn't as noticeable from them...)

Thanks though, everyone!