DAC St-t-t-t-tutter?

This is probably simple and I have my theories, but would like to know how & why this happens:

New DAC (will remain unnamed, but very well respected.) Direct connect to amp.

Feeding source from a 2008 MacBook Pro via USB, 2TB RAID-1 drive connected via Firewire 400. (This source will be upgraded soon*.) Pure Music is upsampling from iTunes. On the MacBook, most extraneous functions have been knocked out, leaving the machine pretty much free to play music.

Things sound great most of the time, but every now and then, the music starts to skip, stutter, and generally scare the life out of anyone listening.

Sometimes a restart of PureMusic/iTunes will fix it, but more likely I can clear it with a simple power cycle of the DAC.

I don't know if this is only happening on HD tracks, or not.

So, what's going on when this happens? Which part of the chain should I be looking at to solve the problem? Any way of avoiding it for the time being?


* Upgrades will likely be a Mac Mini with SSD, Empirical Audio's Off Ramp 5 USB converter running I2S to the DAC.
The computer is stopping streaming data at times.
That sort of issue is always the computer having some other function take priority
Thanks, Elizabeth!

Clearly, I was hoping it wasn't the shiny new DAC having a problem.

Looks like I should upgrade the computer a.s.a.p.

Sounds like a latency issue with the USB interface. Adding more memory to the computer can help sometimes, but it may just be the driver and interface on the DAC.

I recommend doing these tweaks to any MAC:

Get iTunes iBooks:

The Optimization Guide for Apple OS X - Mountain Lion
The Optimization Guide for Apple OS X - Snow Leopard

Steve N.
Empirical Audio
Thanks, Steve --

I've looked toward those books a few days ago, but as far as I can tell, you need an iOS device to read them. I don't have any iOS devices available.

Is there a way to read them on OS X?

Steve --

PS: The new DAC is the second choice on your list. Considering a new DAC versus an older 2008 Macbook Pro, I'd certainly hope it's the MBP.
Rob - dont know about reading the ibooks. I have an ipad but never tried it yet even on that. I got the instructions whan they were still downloadable on the web.

Steve N.
Empirical Audio
Steve --

Well, I guess that puts me out of the running for reading the recommendations, unless they're still out there somewhere.