Yah, I'm missing that bass... and punchy fun of the SA5k. Though I don't think I'll be going back - I hit that sweet spot where the Qualia just sounded right to me. Dunno if it's burn in or acclimatization.
Still, while they sound meaningfully different from the Qualia, I wouldn't say the SA5k are like a totally unrelated headphone. The resolution is one of the defining characteristics I think.
I think the HD600+Cardas sounds pretty darn different from the HD650+Zu, but they're obviously from the same family. I think there's something similar going on, at least for me, between the SA5k/Qualia. This isn't to say the gap is the same, just that there's a different sound, but they're closer to each other than they are different, and they're closer to each other than any other headphone.
Anyway, I think of them like brothers. You know how brothers can be pretty different but clearly from the same family. I don't think I'm gonna call the SA5k the "baby" Qualia anymore.
Best,
-Jason