welcome, its back to you again... how you want to achieve Sound Sig u want?
Balanced cable can give you more dynamic in lower volume, of course with a chance of increasing Hiss.
It really back to the source, e.g. pairing with DX220 AMp1Mk2 , with Mid Gain & mango OS, Volume 8, Balanced 2.5mm, u get dynamic like in the higher volume with Unnoticeable Hiss.
If you want Darker blackground, Switch Gain to Low, but volume already 18 still not getting Dynamic like above... Based on my exp.
Thanks for the detailed answer! Did you notice any sudden pop sounds for dx220? I'm currently on a dx200 with amp4... I'm afraid of hearing damages due to those loud pop sounds... I feel like it pops more with Solaris than headphones as well...