Optical connections are inferior to coax (RCA) or balanced connections. I recently added an outboard DAC to my system (MSB Link). I have 2 CD players - one with a Toslink (a Sony - I know, I'm embarassed) and the other with a coax digital out (a Philips CD Recorder - hey, it was for my wife). I had done A/B listening tests with these CD players shortly after I bought the Philips and heard no difference. The Link DAC has 2 inputs - 1 Toslink (optical) and 1 coax. So I could plug both of the players into the DAC and do A/B on Toslink vs Coax and decide for myself if Toslink was as bad as everyone says. It is. The music sounds a lot "flatter" with the Toslink connection. So If your choice is between Toslink and coax - go with the coax. If your optical connection is AT&T, that's a different matter - I've read that that's agood system, however, I have never listened to it. Either way, Toslink cables are cheap (about $30) so why not by one and listen for yourself - then you can decide with your own ears (the best way always). Good luck!
