theta casablanca 3 audiophile qlty stereo sound?

Depends on your definition of "high end" stereo sound. This is a pricey pre/pro and my experience with pre/pro (in this general range, ie. pretty expensive) is that they can do a very admiral job with 2-channel, but not to the degree that a good to very good 2-channel preamp can do. This being said, I am strongly considering selling my existing (very good) preamp and sticking with the direct pass through analog preamp in my pre/pro (which is a new Krell HTS 7.1 which takes its preamp design from the Krell KCT - the reason I bought it in the first place). I did find after buying it, that it was not quite to the level of a good 2-channel preamp, but have now decided that it is, hopefully, good enough for me.

Stick, my apologies, in my haste, I had attributed what Dan wrote about his and his buddies experience to you.

The benefit of the built-in DACs on the Theta is a matter of opinion in terms of the benefits delivered. Obviously, the better the quality of your CDP, the less benefit the built-in DACs will deliver. However, if one has a mid level CDP or already just has a transport, then the built-in DACs can be a real benefit. This is all based on 2-channel listening. Having them can increase flexibility, no doubt (adding digital sources with either no internal DAC or a poorer internal DAC) or possibly doing away with CDP's in favor of straight transports (nice if one already has a 2-piece transport/DAC and they find that the DACs in the Theta are as good as their existing stand alone DAC???).

Pre/pro don't have HT passthrough in the sense that a 2-channel preamp does. What I believe stick is refering to is either a full analog bypass that allows the 2-channel signal to pass through the pre/pro without any processing (outside of gain in the analog domain) for the cleanest/least compromised affect on the signal.

Typically, HT passthrough refers to a feature on a 2-channel preamp that allows the prepro to deliver its front left and right output signal (that would typically go to the associated amps) for a movie (for example) to pass through the 2-channel preamp without requiring the user to adjust the volume from the preamp, but performing all volume control via that of the pre/pro. This allows one to connect their higher quality 2-channel analog signals directly to the 2-channel preamp, leaving the pre/pro completely out of the 2-channel chain for optimal performance. In essense, this allows one to maximize performance for 2-channel and also for surround sound all in the same system!

You will get better two channel performance with the ARC Ref. 3 and the Cary SLP-05 than the Theta. However, you indicated (or perhaps somebody else did) that you are using the Dreadnaught amplifier. This will be your limiting factor with 2-channel performance. I have owned the Dreadnaught II, kept it for about a week due to its well below satisfactory performance in 2-channel operation. Sold it to a member in NY who wanted to replace his Halcro multi-channel amp with one that was reported to deliver better 2-channel performance. He kept the Dreadnaught II for less than a week and then sold it himself. He too indicated to me that it was weak with 2-channel performance. FWIW, my amp had three of the higher powered monoblock cards/amps and two stereo amps in it, so it shouldn't have been a power issue.

For absolute best two channel performance, you need either monoblock amps or a stereo amp. I have never heard a multi-channel amp do particularly well (I have owned several - Krell, Dreadnaught, Conrad Johnson, and others) with 2-channel performance. Of course everybody has different demands and considerations as to what is acceptable 2-channel performance.

For a 2-channel preamp, you have listed two very good and very different sounding preamps. The Cary can be purchased for much less used than the ARC. Another consideration could also be the Aesthetix Calypso and many others as well.

Stick, your comment that you and your friends were blown away by your current system. This being the case, and my impression that you are totally satisfied, then why change anything? Perhaps you are at the point where the improvements that you may see will not be sufficient enough to satisfy your multi thousand dollar additional investment. There is always "better" equipment to buy, but I find stopping when you are satisfied may be the best solution. Until there is something specific and annoying about your system, why not just keep it where it is? My comments/suggestions made on this site are always honest and straight to the point (at least this has been my intent) - but they are always my impressions and from my experiences (within my system/room). Like everybody else's opinions, they are just that - opinions. My comments and those of others should never replace what you personlly hear and/or like. If you find your system fully satisfying why change?