Tube, solid state, with and without feedback - headphone amplifiers come in all kinds of designs, shapes, and sizes. In this hobby there is no such thing as one-size-fits-all as everyone has his or her favorite. While there are many highly competitve units on the market we all sometimes think "Damn, I wish it had this gain switch/extra set of outputs/something".
I want to see if headphone community that I am part of is happy with the amps its using and what are the defining features of a "good" amplifier.
Even though now it's only a case study I am preparing for my university classes with your help it might turn into something real: a versatile unit focused around your needs.
I would really appreciate your feedback on this: https://www.surveymonkey.com/s/773TTR3