@Maxx134 Thank you for your impressions/comparisons. Yes, I'm using the WA33 w/upgraded tubes to power the Susvara, as well as other headphones, and I do enjoy it very much. I never turn the volume past 12:00, I'm usually listening at 11:00 or lower and I'm very satisfied. I do understand that you pushed these amps to their limit for testing, though. I had the opportunity to hear the Susvara on the PL 150 power amp (not INT) thanks to @llamaluv but unfortunately it was much too brief to draw any conclusions between it and the WA33 because my main priority was to listen to the SR1a/PL which is what I did. I would love to give the Citadel a listen for myself one day in comparison to my WA33, especially due to their price differences.