How to evaluate CD DAC vs. outboard DAC quality


I have a Cambridge Audio Azur 840C CDP that received positive reviews upon is release. If, as I keep reading, DACs have advanced by leaps and bounds over the past several years, I have to wonder if adding an outboard DAC would improve the overall sound quality. My audio goal is always the same: greater musical realism!

So the question is: How can you know whether a recently released DAC (say around $1000-$1500) will be a useful add-on? I'm not looking for the flippant and unhelpful try-it-for-yourself-and-see response. I'd genuinely like to know A) whether modern-day DACs really are superior to those from five or ten years ago, and B) whether someone with a large CD collection and no interest in computer audio is better off forgetting about a DAC and investing instead in a better CDP, like Ayon or the like.

Thanks!
recroom
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I was using a Sony 5400 as my digital source. Then purchased an Audio Note Kit Dac 2.1b for $1750 using the Sony as a transport. Major inprovement over the Sony especially in information retrieval and frequency extension. I have now replaced the Sony with an Audio Note CDT Two/II transport. Another major improvement proving to me that the transport is just as important as the dac
Alan
I agree with Elizabeth. Newer isn't akways better and there are other factors involved in how a dac sounds besides the chip used. It's like a quality 100 watt amp sounding better than a crappy one that's rated at 1,000 watts. I can't hear a difference between my parasound z-dac (which got and is getting rave reviews? And my musical fidelity a3.2 cd player (that got ok reviews). Buy a dac that you can return once you've heard it then you can decide for yourself!
Although one may experience improvements from one DAC to another, they are usually quite small and subtle. The best chance to enhance that "greater musical realism" you've requested is to buy much better speakers than what you're currently using.