You obviously have a great investment in your Linn system, so if you want to incorporate your new Mac G5 as a digital music server front end to your Linn system, get a Lynx Studio Technologies Lynx 22 which has balanced analog I/O and S/PDIF digital I/O. Depending on what you prefer, you can send the signal into your Linn control amplifier from the analog outputs, or into your DAC (if you have one) from the digital outputs. Most professional audio engineers love the Lynx products for their quality AD/DA processors which rival those of much more expensive outboard DACs. Lynx offers Mac OS X drivers as well for the card (i.e., full Core Audio compatibility). The Lynx 22 and its slightly more expensive sibling, the Lynx 2 (Version B), contain internal clocks for reducing jitter distortion and for creating a clear and deep soundstage. These really are great bargains when you think of the audiophile performance you can extract from these devices. Together with your Mac G5, you'll have something far superior to Linn's Tunboks.