I've compared the HM801/JH3A and CLAS/co-ax/JH3A and have reached my own personal conclusions on how they differ.
This is purely subjective and based on the limitations of my 56 year old ears.
Detail - no difference.
Separation - no difference.
Soundstage - no difference and, unsurprisingly less pronounced than Senn HD800/CLAS/iBasso/SR71B/balanced Twag.
Is there a difference? Yes.
Is it important? To my ears yes.
Having used my reference live recording of Brahms Violin concerto recorded at the Sage Gateshead (Northern Sinfonia; Thomas Zehetmair conductor/Soloist) I discovered something quite extraordinary. To explain I need to go back to the actual concert where I was struck, not only by Zehetmair's technical brilliance but also the emotional content. I've listened to the recording under a number of different setups: Griffin CD player/Stax srm 007t; HM801/Headroom portable desktop amp/HD800 as well as the above configurations. All impressive in different ways but only when listening via the HM801/JH3A did I noticed something the others did not provide. At first, I thought I must have misheard, and so replayed the section several times until I satisfied myself that I wasn't imagining things.
Finally, I concluded that the HM801/JH3A provided what I can only - and very poorly - describe as an emotional rendition of the soloist. The live recording is from 3 years ago and memories fade but for the first time, since the concert, I actually felt moved by the piece. Sure enough, there were no more details but the music appeared to be imbued with something which made the CLAS/JH3A combo seem, not 'cold' but less involving.
I was surprised, but I can assure you that it was real and each time I replayed the section there it was - I became emotionally involved with the music in a way that none of the other combos have done.
By the way, in response to a direct email I reported that I didn't think adjusting the bass control would have any effect - I was wrong. In all my classical listening, thus far I have found a 30 degree adjustment has enriched the sound.
Hope this is of some use to some of you.