I need help choosing a DAC


I'm new to the USB DAC world so I'm hoping you can help me determine which of your products is suitable.

Here's how I'm doing things now:

- Mac Mini
- iTunes for ripping and organization
- Front Row or PLEX for consumption
- CDs ripped at full AIFF or Apple Lossless or purchased FLAC
- Toslink cable from the Mini leads to an Integra Preamp (internal DAC) - amplification, etc.

When I want to the music to really shine, I use a BDP-83 as a transport and just listen to physical CDs. I love the Integra's DAC and just wish it had USB capabilities.

A/B comparisons between AIFF/Mini and CD playback reveal the following:
CD has better imaging and a wider soundstage, more detail and decay in the high end but still warm.

Do you think I will get better sound bypassing the Mini's sub par optical port and moving the data via USB? If so, which DAC is for me or is there a way to convert USB to coax (to Integra) without screwing the sound?

Anything that makes the music sound more digital or adds grit to the mids and highs is not desirable.
sjc1204
An M2Tech hiFace USB>SPDIF adapter should be on your short list if you want to keep your present DAC.
USB-to-S/PDIF converters:

Bel Canto USB Link 24/96 USB-S/PDIF converter. Here's Stereophile review: http://www.stereophile.com/budgetcomponents/bel_canto_usb_link_2496_usb-spdif_converter/index.html (now $249 instead of original pricing of $495)

M2Tech Hiface (supports 24/192 files). Here's 6Moons review: http://www.6moons.com/audioreviews/m2tech/hiface.html
This one received 6Moons' Blue Moon award. This would be my choice at $150-$180 and supports full hi-rez files.

USB DACs:

Too many to mention. What is your budget? You can do HRT Music Streamer II ($150) and II+ ($350) all the way up to Ayre's QB9 ($2500) and more expensive offerings from Wavelength. There are many other DACs that have USB ports but the ones mentioned above are optimized for USB and use one form or another of asynchronous transfer mode, where the DAC slaves the PC to the DAC's clock, reducing jitter and to my mind is the superior DAC technology via USB port.

You should check out Computer Audiophile (http://www.computeraudiophile.com/). Many good resources and reviews there for everything related to computer-based audio.

Hope this helps.