A couple of updates...
1) HEK are being returned. While their treble is better than the Abyss, they lack the dynamic power, punch and soundscape of the Abyss. Although to be fair, *any* other headphones sounds lacking to me now. The speaker-esque presentation is perfect for my tastes.
2) Will be ordering the new Eddie Current Studio amp. Craig used the Abyss to develop the amp, and apparently it's stellar. 2A3 based but with top spec premium parts throughout, hence more transparent and dynamic.
@SpherE22 : I've auditioned the Ragnarok (with Hugo) and preferred the Moon 430 by a
considerable margin. It's an incredible machine, and with the onboard dac, it's amazing for both day to day desktop use and serious extended listening sessions. Musical/coherent while retaining dynamic range and resolution. Quite a few people on this forum own one and have tested many other top SS amps. Powers the Abyss comfortably.