[linux-audio-user] Poor SN ratio with high quality sound cards

Gentlemen: I follow this list from the digest, so I could have missed a critical post. If so, please point me to the thread. I have two PCs I use almost exclusively for sound editing (with ReZound --- highly recommended for its crossfade ability). I record classical music on an Alesis MasterLink at 96kHz/24 bits, so I have quite a SN ratio to begin with. I need to edit the gaps between tracks where I want to preserve the hall ambience. Whether I use an RME Digi96 PAD or an M-Audio Delta 44, the signal I get out of the sound editor is so low that I hear a lot of hum and other extraneous noise by the time I crank my amplifier's volume up enough to hear what is between the pieces. This noise is _not_ there when I burn a CD-R, however. I assume this means I need to send a digital signal (preferably 96/24 and lower) to an external DAC before sending the signal to my monitoring system. Would someone be kind enough to explain how to get a signal out of a PC that is fully equivalent in S/N to the CD-Rs the computer can burn? Many thanks, John