Benefit of a Newer (Used) DAC - "Bang for the Buck?"


Despite having a SO who fails to understand why anyone would spend more than $100 on a “radio,” I’ve managed (over several years) to covertly assemble a fairly decent home audio system.  (My prize acquisition being a $500 set of LN Belle Klipsch loudspeakers off CraigsList).

At any rate, relying on quality used equipment that is past its technological “expiration date” has, under the circumstances, served me reasonably well. However, I’m now to the point where I’d like to (again) update several components – namely, the DAC.  

I’m currently running a Cambridge CXC transport through a Genesis digital lens and a Muse Model Two DAC – both of which, while fully functional, are fairly dated.  Realistically, how much noticeable impact can I expect from a newer (used) DAC – like a Bryston BDA-2 or MHDT Pagoda (for example)?  FWIW, my current setup does everything I need it to (i.e., play Red Book CDs).

In advance, thanks for any advice/feedback.

tds3371
Maybe read up on the RME ADI-2 . I've had demo model for a week. It's real nice. 
Actually, @audio2design, you've answered my question:  Is money expended on replacing an old DAC likely to result in an audible upgrade?  Sounds like it will - even it the replacement is an entry-level version. That's all I needed to know; I can now move forward re: model specifics.

For the record, the Belles I own were manufactured in 1984 - and have new Crites AB-2 crossovers.  The original Klipsch AB crossovers in these speakers were not particularly good; Bob won't even rebuild them. Production of the Belles was phased out in ~2005.
There are a lot of excellent DACs below $1K (new and used). In addition to the ones mentioned, I'd look at the Denafrips Aries II (new for about $800) and the Schiit Gungnir MB (used for about $950).
If and when I can travel again, I want to get a high end "travel DAC" for headphones.  Was looking at the RME ADI-2.