Hey there.
I also want to try these headphones on my Fiio M15s. I just read than an Ibasso 320 can handle them (exactly the same 1.2W of power output as the M15s so perhaps can be ok).
Could you try them since you posted this message?
And does the He1000 v2 would sound really better than my Focal Clear ? I mean a big step up. I want to try something new but I must admit that the clear with some little adjustments is already really good
I can probably comment on this as I was using primarily Focal Clear and HE1000 v2 (non stealth) for a few months before I just recently upgraded to Focal Utopia a week ago. I will comment on each headphone as I hear them.
Focal Clear: Narrow soundstage, can sound a bit congested (still more open than Hd6-- line). Lower mids fairly prominent relative to upper mids, though nothing is too boosted, but because there is a boost around 1-2k, and a recession around 3-4.5k, it can seem a little exaggerated on lower mid warmth. A bit metallic in timbre, i hear some ringing up there past 12k which can be annoying on certain tracks. Source pairng helps but cannot eliminate. 6k -12k is slightly laid back compared to neutral further emphasising midrange (particulary lower mids). This ultimately leads to a somewhat congested experience that is intimate. Slam.
He1000 v2: Very open and grand, separation is much better giving instruments and vocalists air. Can sound a little bright at times (if you are sensitive to 4-6k) but mostly very controlled. With right source pairing, can definitely be controlled to be less peaky in this range. Very very rarely sibilant. Typical Hifiman scoop at 1-2.5k. This is not offensive, but exists. I think it honestly helps with the presentation of the headphone as I tried to EQ in this dip and it sounded weird (really wide and tall, but depth was severly hindered). Smooth sound that is easy to get lost in the music. Does not have the dynamics of the Focals, both micro and macro (bass does not slam nearly as hard and cymbals are more sizzly and soft rather than having the crisp clang - hard to explain, I think has to do with planar timbre people talk about, that plasitcy sound?). More of a laid back presentation in this sense. Transients are great however, guitar plucks in particular sound tangible.
Focal Utopia: Narrow soundstage, but not as bad as Clear. Good depth and layering, but not particularly wide (though its fine). More filled in around 3-4.5k than Clear so its midrange is less wonky, even with the same 1-2k boost. Treble is well controlled and there is no metallic timbre like the Clear. Intimate, but not congested. Imaging and layering is amazing. So much that I can notice small channel imbalances of less than 1/2 db in narrow bands within the midrange. I think timbre is the best here (considering tonal balance, transients, dynamics), even though I actually prefer the HE1000 v2 tonal balance more from stock. Slam, but more controlled than Clear (I think touch less midbass and more sub bass extension?)
But anyway, if you got here, appreciate you taking the time reading my impressions. Just wanted to share as I am hot on these exact headphones you may be interested in. Unfortunately never tried any other He1000 variants.
EDIT: Utopia's are 2020 variant.
