Opposite of my experience.
Had three speaker amps (5yr,10yr,25yr) never had issue.
I believe timimg of what brand & year is the issue as there was time when mass market garbage was prevalent.
It will start to tap out around 3/4 Volume, as most headphone amps do with Susvara.
That being said, it does sound extremely good with the Susvara.
Yet, You really need a speaker amp if you want Susvara to reach it's full potential.
You may not even realize this untill you try.
At full potential the Susvara is the most complete headphone you can own, "ticking all the boxes".
Nothing lacking. No weakness in any audible area. Perfectly layered soundstage and resolve with good bass(depending on amp).
Cant say that for any of the other TOTL headphones:
**Stax009 = detailing/speed(over accentuated details & agressive)
**HD800= soundstage & detailing(no planar bass, accentuated/agressive trebles)
**Abyss Phi= juicy large bass (bass heavy overall, slight dip in lower trebles.)
**Raal ribbon= large image height & top level resolve(a bit forward & les sub-bass impact, like an hd800)
**Empyrean= less soundstage image than others memtioned & slight warmer signature overall.
Of all these the Raal ribbon & the Susvara were the best to vanish and give you the sense of being at the recorded event. Both were driven by the Pass Labs INT-150 when I compared.