Theo - you are in luck. The best coax cable you can get is only $250 from Empirical Audio, called the BNC-BNC cable with RCA adapters. My customers have had shootouts with all kinds of cables. This one always wins. read the reviews on my forum:
http://www.audiocircle.com/index.php?board=40.0
Purchase at the pull-down menu:
http://www.empiricalaudio.com/products/off-ramp-converter
You might want to consider a reclocker for the Sonos. This installs between the Sonos and DAC and makes the biggest difference in sound quality. Bigger than the cables for sure. The Synchro-Mesh is a reference reclocker. Most of my customers use it with Sonos:
http://www.empiricalaudio.com/products/synchro-mesh
It also has an optional upgrade power supply, the Dynamo. With the Synchro-Mesh powered with the Dynamo, you will have a reference quality digital source.
Steve N.
Empirical Audio
http://www.audiocircle.com/index.php?board=40.0
Purchase at the pull-down menu:
http://www.empiricalaudio.com/products/off-ramp-converter
You might want to consider a reclocker for the Sonos. This installs between the Sonos and DAC and makes the biggest difference in sound quality. Bigger than the cables for sure. The Synchro-Mesh is a reference reclocker. Most of my customers use it with Sonos:
http://www.empiricalaudio.com/products/synchro-mesh
It also has an optional upgrade power supply, the Dynamo. With the Synchro-Mesh powered with the Dynamo, you will have a reference quality digital source.
Steve N.
Empirical Audio