This is the problem with being a Neil Young fan who has collected nearly 30 years worth of Neil CDs within the HDCD era. Of course the "problem" is solved if you are OK with replacing everything in your collection with hi-res files, as you can mostly stop worrying about HDCD decoding. For 25 years I had an old carousel Denon CD player hooked into a Parasound DAC that handled HDCD. But when the carousel player finally broke down, I upgraded to a new CD player (two years ago) that has USB capabilities. So I obtained lots of hi-res stuff on memory sticks that replace HDCD discs. But there are some things that have not been replaced and this new Denon DCD-800NE CD has a great DAC (superior to the Parasound) but it doesn't decode HDCD. Fortunately, I still have the1995 Parasound external DAC that handles HDCD. So I can listen three different ways now:
1) Denon CD player analog out to my 2009 Denon receiver. (Denon 800NE CD player DAC, no HDCD)
2) Denon CD player digital out to the Parasound and then analog out to Denon receiver (Parasound DAC, HDCD)
3) Denon CD player digital out to Parasound and then digital out to the Denon receiver (Denon Receiver DAC, HDCD)
I can choose from three different DACs and compare. I do hear more bass through the Parasound (#2: analog out option) when playing HDCD discs compared to not using it and just playing them straight through the new 800NE player (option #1). If I do digital out from the Parasound into the receiver (#3), I think I am still getting the HDCD info decoded before the receiver's DAC takes over, but the volume is lowest using this option and makes it sorta hard to compare. It seems that usually, the overall sound is best skipping the HDCD decoding and just going with the first and simplest option: Denon 800NE CD player analog out to receiver (example: Neil Young Archives II HDCD discs sound VERY smooth and good in option #1 that decodes none of the HDCD data). An exception seems to be Mirror Ball. It does sound best with option #2. And I found a disc that seems to sound best using the 3rd method (HDCD Big Time single with bonus tracks).
So to summarize this mess, new DACs that can't do HDCD may sound better than old DACs that can but there are occasional exceptions. If you can upgrade to hi-res, do that. Or you can try doing all that laborious computer work with the fancy programs to turn your HDCD discs into files if you are into that sorta thing.