Benchmark DAC1 vs CAL Sigma

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.

Craig, I purchased the Sylvania 5751 from Audiogon. But I often buy new tubes from thetubestore.com, and I've had great service from them.

Michael

Can someone respond to the original question? I, too, have a Cal Sigma I and II, and have had good experiences rolling tubes for this DAC. However, I want to hear about options for the next step up. Insights or comparisons with PS Audio DAC, Benchmark, Bryston, or Bel Canto 3 will be especially appreciated. Com'n Audigoners, us Cal Sigma owners await your insights to help us evaluate our next DAC. (FYI, my transport is the Sony SACD/DVD 9000ES.)

Thanks for the responses everyone!

Lostbears, my Sigma is pulling 'dual duty' for me. I am running pc based audio into it via a digital coax cable, and I am also running an Oppo DV-980h into the Sigma via optical cable so that I can enjoy concert DVDs through my 2 channel stereo system (such as Diana Krall's Paris & Rio concerts & the many outstanding jazz DVD offerings from Jazz Icons such as Anita O'Day, Ella Fitzgerald, Art Farmer etc) I flip a switch on the Sigma to go from coax to optical input.

I have a Doge 6 Tube CD Player for redbook CD, but I have to say that that playing redbook CD through the Oppo/Sigma combo sounds ALMOST as good as it sounds through my $1500 Doge-save for this bit of shrillness that I mentioned in my original post. Here's the rest of my system:

ARC LS-3 Preamp
Bryston 4B_ST Amp
Doge 6 Tube CDP
Oppo DV-980h Universal Player
Revel F30 Speakers
Morrow Audio MA-2/SP-2/MAP-2 Reference Interconnects/cables/cords