I have a Sigma II and it really is a nice DAC. What are you using for a transport? When I replaced my old Delta with an newer transport it made a world of difference. I now use a Audio Research CD7 for CDs. But I still use the Sigma II for my computer audio server. It replaced a Musical fidelity A324 upsampling DAC that I thought the CAL bettered.
Benchmark DAC1 vs CAL Sigma
I have an old CAL Sigma I in my system. I generally like the sound, it's musical & dynamic, however there's a bit of shrillness in the top end that I find off putting. I'm wondering how different a modern upsampling DAC such as the Benchmark DAC1 or a PS Audio Digital Link III would sound in my system? I'm a bit of a noob with external DACs so any input would be greatly appreciated.