HELP USB to DAC = Loud Bursts of Volume

Okay, I have a Macbook Pro and a Bel Canto Dac 3. I have gotten intermittent loud bursts of volume when I am connected via USB. This has happened 3 times at least in the last month. The volume setting on my Dac/Pre has not budged and I have no idea what is causing this. It just all of sudden goes to like MAX volume. I quickly turn the amp off or unplug the usb to avoid damage to my speakers.

I have never had this problem when I stream wirelessly from Airport Express to the Bel Canto's optical input.

Anyone have any idea what is going on? I called Bel Canto and they have never heard of such.

Haven't had this problem. My instinct is that it is related to specific tracks and how they were acquired. Here are some trouble shooting ideas:

Is all your music ripped the same way? For instance did you start by doing MP3 then move to Apple Lossless? Are you intermixing Apple Lossless with material from the iTunes store or other online downloads.

Is this happening randomly or to specific albums or tracks. (If so it might be worth reripping them)

Take a look at the settings on the specific tracks involved. Select the song in the iTunes master and Get Info. Under Options see if there has been a Volume Adjustment or Equalizer Preset applied. If either case is true, turn them off.

Also under Summary see if the basic specs match the way everything else is being ripped - in particular there is a Volume setting, if it is reading in + territory that could be an issue too.

When you are ripping are you using Error Correction? (under Advanced/Importing)

Also might check the Apple boards

Good luck
In the recent past I used a Mac G-5 wireless to Airport Express. When my wife used the Microwave to cook something I would get a loss of signal. Weird! Other than that Airport Express never gave me a problem.

Is your Airport Express encrypted? Someone may be trying at access your network. Can you connect the Macbook directly to the DAC? If you can see if it happens again. Also go the and check the FAQ's, see if anyone else has had issues with the Airport Express.

Good luck
I have exactly the same set up, and exactly the same issues.

I can only tell you that each time this has happened, I've touched
the MacBook Pro, and received a sometimes barely perceptible static
shock ( but sometimes the static shock was very perceptible and almost
lit up the room! ).

I intend to contact the nice people at Bel Canto about this
for their advice. If I reach them before you do, I will file a report here.

It is *very* disconcerting, and I was afraid each time that I might
have damaged my speakers.

Can you recall any of the actions/symptoms I've outlined above?
A follow-up to my previous post, which is awaiting approval ...

This sudden volume 'up' has nothing to do with which tracks
happen to be playing, or wireless, or anything else, I'm 99% sure.
It's happened to me at least a half-dozen times, and only at
moments when I've touched the MacBook Pro, while music
is playing.

I do think it might have something to do with the MacBook Pro's
aluminum casing, and a build-up of static electricity. But that's
only my best guess at the moment.

It really is the darndest, and strangest, and scariest thing.

Tweeters still intact, so far,

It has only happened when connected via USB and while music was playing. Once you mentioned static a light went off. I am sure that at least two of the times this has happened, it was as I touched the MB Pro, and I distinctly remember static electricity. I immediately killed the music because I was concerned for my speakers.

It makes perfect sense to me now, because before I upgraded to the Pro, I had a Macbook for a few weeks. The issue never happened as the Macbook uses plastic casing.

I will call Bel Canto again tomorrow and ask for Matt and I will make sure to mention that I am not the only one having this problem. Hopefully they can resolve this issue. I have resulted to using the Airport Express again, not that it sounds bad, but I prefer the USB set-up since the general consensus is that is sounds better than using the AE.
Guys - if Bel Canto fails to provide satisfaction, you might consider trying the Opticis USB cable. This is a fibre optic cable that lives between the USB output and the USB input. Net effect is that it provides complete electrical isolation between the computer and the DAC - meaning that it might be a way around your static issues.

I would be pleasantly surprised if Apple acknowledged this problem, but some of the Mac tech sites might have some coverage.
Ckorody -- thanks for the tip.

I think both of us plan to move to Mac Minis in the near
future though, which, given the circa $200 price tag
for the USB-to-optical-and-back-again cables,
probably makes the most sense, all things considered.
But thanks again for the tip.