HISS,
for me, yes there's a slight Hiss for my Combo (also with Solaris) and AMp1Mk2, Mid Gain. but as long the mid is this rich, I willingly ignored it...
Based on my exp, AMP8 can delivery darker background...
Burn in,
I don't trust it, especially in long hours... at the beginning...
but DX220 and My sensitive IEM do change after break in / burn in... so Its true...
My exp, AMP1MK2 after 70 hour Mid started layer. getting refine after more hours.
AMP8 more change on Low...
in the end, I enjoy it... never change or change my gear combo eversince... (except cable)
wish I meet
@ddmt here in land of the Gods... want to try that Z1r and VX....