I went through a period during the lockdown when I was trying out all kinds of headphone amps, tube and SS - in addition to the Nirvana, I also had an Enleum 23R and an Oor stack and a DAVE and an M Scaler, and except for the Eddie Current and the Nirvana (which is currently up for sale), I sold all the rest. Yes, they all did bass harder and fatter. Didn't matter to me, the rest was so good, and with the right source, the Susvaras will still vibrate the bones. Nothing like a tube amp with some extra special mojo, like the 300B and I've no doubt, the Stratus....