yes fair comments, peter.
I have a pcm1794a driven by cs4816 receiver.   
to confuse things some more. I played a 96K track this morning (Carol Kidd, Linn record) with exactly the same setting as before (DAC is 192/24 no upsample), the setting that gave me error message. It just played, no error, no hassle!!  This is the same track that required me to change to DAC is 96/24 yesterday.
thanks for the explanation on sample rate stuff, I still don't get it, but will read that again.  (and ask questions aagain).
regarding "never use upsmaple"
I had insisted on "bit perfect" for a long time, but had changed my mind (your writeup had some influence), because modern DACs are all oversampling devices (they sound better than old designs).  so by the time the real DAC sees the bits, they are no longer "perfect"; they had been messed with either by software or internally in the chip.  As long as someone will mess around with my bits, I might as well find the someone I like.
regarding "and which is always a poor implementation of something which just *is* necessary". 
Until I can completely switch from redbook CD to HD tracks  (BTW some HD tracks aren't any better.  eg 88.2K Jazz at the pawnshop from HDtracks.com), I am stuck with it.  How do you disable the internal filtering?  pcm1794a allows for external filter, but I have not yet tried that because I have not found an external filter that is really attractive.  pacific microsonics pmd200 has good reviews, but is extremely rare.  building one out of DSP seems too much work.  maybe there is a way to trick pcm1794 into thinking there is a phantom external filter.
Again, I completely agree that NOS1 DAC is the way to go, I just need some time to save enough money.

I have been listening to these two players for days now.  Both are very good, truly heads and shoulders above foobar , winamp etc.

now quick comparison

HQplayer sounds much better in my system.  I switched to xxhiend again earlier today and could not wait to return to HQPlayer.  I like every respect of HQ sound over that of xxhiend:  details, sound stage, imaging, space, dynamics, bass extension and on and on.

HDplayer is much faster in putting a track into play.  I understand from PeterSt's write up that he fully processes the whole track before playing.  I believe thats true from the latency time which also depends on whether it is 44.1KHz or 192K.  Effect of changing volume is also longer in xxhiend, this is dangerous because I over cranked the volume a couple of times.
 
the xxhiend UI is better but not by much.

The relationship between upsampling target and DAC requirement is very confusing.  I specified dac requires 192/24 but keep getting error when I tried to 4x upsample redbook CD to 88.2K.  same error message when I tried to play 96K tracks; I had to redefine DAC to be 96K/24. There is no choice for 88.2/24.  very confusing and inconvenient.  I had read through every topic Peter wrote for dummies and newbies, but still am not enlightened.
 
both players clicks between tracks, hqplayer less so.
 
I do love PeterST's NOS DAC project  I think that's the future.  Will start saving money.