Shane D
Headphoneus Supremus
For my HE6se V2's, and pretty much any planar, I use my iFi Pro iCAN.Fortunately, I never saw any red light come on my SA-1 (knocks on wood) but my anecdote won’t mean much.
I know what you mean about the LP - it could’ve really used a gain switch. I really like the sound it makes with my Arya but I can’t use it with my Ares II dac because there’s some channel imbalance at around 9:30, which is my preferred listening volume. Moving past 9:30 resolves the imbalance but then it’s too loud. Rme is a good alternative since I can control the volume (unlike Ares II) but I’ve grown to realize I prefer the r2r sound.
As for volume play with your headphones, I’m sure you’ll be fine. I only stay in low gain on SA-1 (sounds tighter to my ears) and never felt the need to go higher. I’m at 3:30-4 on the HE6v2, around 2 for Arya, and 11-12 (I think) for the Elex. Can’t remember for HD6xx. I have a hearing of a late forties male. Ymmv and all that.
My favourite amp is my Violectric V220.
I am a quiet listener and most of my headphones are pretty efficient.
And I see a used SA-1 for sale in my area...No warranty, but it's almost half price.