Many people refer to the sound of the DSP adjusted audio when talking about Amarra, HQ Player, Audrivana, etc… Remember, most of those systems alter the bits. For example, HQ Player is universally lauded for SQ, and it is all about changing the bits.
Now, assuming we are leaving out all the non-bit perfect stuff, including HQ Player…
I disagree, they do not sound different. If interchanging bit perfect players in your systems makes a difference when playing back bit perfectly, it is the other stuff downstream that sounds different, not these players (ignoring for a moment that it might also be placebo).
If your system downstream can be impacted by minute differences in acoustic noise, electrical noise, magnetic interference, etc, then you should work hard to fixing the downstream devices, as they are screwing up the sound in the analog phases (which includes the digital to analog conversion).
I have written about why digital audio can’t have fidelity problems but can have an impact on the final fidelity of the audio here:
If you feel your bit-perfect player is making your DAC/Amp/Speakers sound worse, isolate the player physically, acoustically, and electrically from the DAC/Amp/Speakers. Even if your DAC/Amp/Speakers are impacted by in a way that results in poorer fidelity when using program “A” vs program “B”, nothing could be better than removing all impact. You can achieve that by physical, acoustic, and electrical isolation.