Craig,
I also have a CAL DAC (an Alpha). I haven't heard the Benchmark but I can say that my Alpha sounded SO much better with Sylvania 5751 tubes. Have you tried a different tube in your Sigma? That might help to reduce your problem with it, as you "generally like the sound".
Michael
I also have a CAL DAC (an Alpha). I haven't heard the Benchmark but I can say that my Alpha sounded SO much better with Sylvania 5751 tubes. Have you tried a different tube in your Sigma? That might help to reduce your problem with it, as you "generally like the sound".
Michael