Why buy a DAC when you have a high end pre/pro?

I am reading all this stuff about buying high-end DACs to bridge the gap from PC to system. Why aren't more of you running a signal adapter from the PC to your Pre/Pro or Receiver? Many Pre/Pros and Receivers have excellent DACs. We spend big bucks on these pre/pros and then ignore the DAC capabilities. Your thoughts?
I agree that in some cases this is possible and even preferable, especially for processors that use ADC for their analog inputs. I have a Meridian system that gets direct digital stream from the PC and keeps everything digital right out to the the speakers. If I were to use a DAC, the Meridian would just ADC the signal, only to DAC it again for final output to the amp/speakers.

On the other hand (and in the other room) I have a BAT tube pre-amp with no DAC capability and use an outboard processor there. So it may be a necessity for many a'goners since there's a preponderance of purist, two-channel non-digital gear already in place.
Kjweisner: But I'm suggesting that this a DAC transfer. It comes digital out from the PC or Mac and into the Digital "in" of the processor. The Processor, in turn, does the DAC work and gives the speakers an analog feed. Maybe I'm just not understanding what the need is for ADC. Enlighten me please!
I'll be the first to admit that I am not a total expert.
I've done this for quite some time - PC digital SPDIF output to a Lexicon MC-12 digital in, which uses the internal DACs to convert to analog. Very nice and a minimal number of boxes.

I have recently changed a fair amount of gear and now have a 2-channel preamp without built-in DAC, so I will have to get an outboard DAC. But, I would answer your question by saying if you have a high-end pre/pro with quality DACs, I don't know why you wouldn't do just as you suggest.
More of the audiophile things. Sweeter midrange, depth, imaging, less congestion and so on. As always these sonic features may not be worth the price and hassle but only you know whether it's worth it to you or not.

I found that a $200 Cal labs tube DAC did all these things and worth it to me.
No SS processors or receivers currently match the quality of a good stereo DAC. I have one of the most musical ones, the Proceed AVP, and it is fine for movies, but my DAC's blow it away. Not even close. My system is world-class though, very resolving and low-noise. Completely modded out.
Audioengr: I took the time to read a review on your Proceed AVP (it was very complimentary) and one of the highly touted features was the internal DACs so I have to imagine that your external DAC must be really special.
I did start using my CDP as a transport and noticed an immediate difference (for the better) by using my Krell Pre/Pro as the DAC. I guess you start with the Pre/Pro or Receiver and then experiment from there and take note of what your ears are telling you. Budget also becomes an issue for most of us.
You are right. If you had a high-end processor like the Theta Casablanca, there is absolutely no reason to buy a separate DAC.
I've been wondering about the same issue for a while. I haven't currently delved in, so my comments are based on reading.

You can buy a used Proceed AVP or Theta CasaNova for less than 1000. Some commonly mentioned DACs are the Benchmark (around 1000), the Del Canto (2500) and the Musical FIdelity xDac (like 1500.)

So it seems a matter of how much you want to invest. A true high end DAC can exceed the price of a very nice pre-pro. So it makes sense that it would probably better the pre-pro when you consider the many functions of the latter. With that said, the pre-pro is pretty versatile and something like a used Proceed or Theta are big bang for the buck.

Just some thoughts.
Sorry I've been late to respond back, Puerto. I was agreeing with your original point. What I stated about ADC applies when the chain is Digital Source > DAC > Processor > ADC > processing > DAC. In other words, if you have a digital out from the source and you throw a DAC in the chain before the processor, it may well be that the processer immediately (and without option) does an ADC. This would be the case with Meridian for example.

I guess I meant to say that adding a DAC in that specific instance is actually a negative since it causes two more conversion steps to occur.

But for many (those without high quality digital domain processors) the outboard DAC is better than a cheap one that my be "onboard." But only if they have an analog pass through (that avoids the ADC - DAC step in the processor). Sorry I was not more lucid!
Kjweisner: No Problem - I got it now! We are on the same page.
Bmdduck: Your thinking is perfectly logical. Putting your Pre/Pro to the test first seems to be the best first step. One can always add a DAC (and more money) if the pre/pro is not living up to the listeners expectations. I certainly don't mean to imply that money spent on a good DAC like the Benchmark or Bel Canto, for example, is a waste of money. . . It may very well be the next step up the ladder for those who want more! My budget tells me exactly how much I can't live without!