The Feliks Audio Envy is an amazing tube amplifier that is powerful enough for even the most demanding headphones, namely, Hifiman Susvara. The Envy provides endless power and effortlessly drives the Susvara to their fullest potential. Every headphone that I have tried whether planar magnetic or dynamic driven, sounds sublime on the Envy. The Envy brings out the fullest potential of any headphone and there is no reason to look any further. This amp is expensive but well worth the price of admission. The build quality is top notch and on par with amps costing way more. If you are on the fence, get the Feliks Audio Envy now, you won't be disappointed.
An absolutely amazing amplifier for the susvara, 1266, zmf- pretty much everything I’ve thrown at it has sounded better than before. Definitely worth the cost.