I have never used the Jotunheim as a headphone amp. I bought it as a preamp. It is a great deal at $499 with the phono card. I am using it in my main system. My next major purchase will be a Decware tubed phono stage, but I can live with this one without feeling deprived.
To move up to a better phono stage than either the Mani or their phono card you will be to spend five to ten times more. The Jotunheims I have are the old model...not the Jotunheim 2. The second one I bought as b stock...no returning it. For headphones it does have a quarter inch jack and a four pin XLR for balanced headphones. I recommend getting a DAC with balanced outputs If you don't have one. The Modius or the Bifrost2 would pair nicely with it.
Like I said I love it. It is versatile and offers three inputs. I don't see me ever paying for one of their USB only DAC cards. A stand alone DAC gives you a USB input for a streamer and coaxial or Toslink for a transport.
