Which DAC is supposed to be better?

No idea. Depends on DAC chips, architecture, the output stage of the Sony, shielding, power supplies, whether the Rotel converts analog signals to digital, etc. The Sony's probably a decent transport so I think you're on the right track with a DAC(especially since you don't hear much of a difference between the Sony and the Rotel), but I'd go with a coax digital connection over toslink if possible unless you're using more than 1.5m length.

I also don't know about the CAL Sigma DAC, although I know CAL makes some good stuff. I do know that the EVS Millennium DAC II competes with some of the best out there, and at $1050 and a 30-day risk-free trial period my recommendation is you give it a try. Given the level of detail and soundstaging capabilities of the Thiels(I've always liked the CS1.5s too) I think you'll be amazed at what the EVS DAC will do for your system. I'm running my EVS DAC through a Rotel RSP980 and the improvement was not subtle over a modified MSB Link DAC. Check out the EVS website at www.tweakaudio.com for more info, and the reviews on audioreview.com and stereotimes.com to see more complete descriptions and comparisons. (If the RTC965 digitizes analog signals I wouldn't bother with a DAC until I got a new pre/pro or a stereo preamp with an HT passthrough). Best of luck.

Tim

Tim: I currently have a Cal Sigma II DAC with the 24 bit upgrade in "as new" condition listed here at Audiogon for $550 shipped. Understand it is not my intent (nor has it ever been or should it be) to use this discussion medium to hawk a sale. Merely, I noted your reference to the Sigma and thought you might wish to first consider demo-ing IT in your setup, as an alternative to spending say, $500 more on the otherwise well-founded aforementioned suggestion of the Millennium DAC II. Please note this is in no way intended to disparage the highly regarded Millennium DAC. Rather, it is to inform that you have presently the opportunity to experience hands on, this excellent, latest iteration, Sigma II tube DAC unit and if in fact you should find that it's not quite your cup of tea, you can always turn around and pump it out for pretty much (if not absolutely 100%) what it cost and move on to something else. IMHO, synergy is the be all and end all of any system of components and it doesn't always or necessarily hold true that more expensive will result in an improvement with one's associated equipment. Clearly, the more you can experience/experiment first hand without costing you anything, the better.

Hey, sorry guys (Leo and Tim): I see I mistakenly addressed my response to Tim, instead of Leo.

bel canto dac1 0r 1.1

If you do not require more than 48khz a used Audio Note DAC 1.1x or DAC 2.1 is a wonderful unit and will delight you. The used ones have been superceded and you can usually pick something for 30 to 40% of original retail. I use a DAC 1.1x that I will be selling to upgrade to a DAC 3.1 soon.

Regards,

Crl