I have both A3 & Jot 2 - if we are just talking about Single-Ended since the A3 does not have a balanced i/o, IME the Jot 2 has a slight edge in performance all around with timbre, details and staging. If you already have an A3 and are not looking to add balanced capabilities to your chain there is no real super compelling reason to upgrade. The A3 is a stellar performer @ only $200 USD retail even better on the second owner market @ $150 USD.Has anyone compared Jot 2 to A3?
I would imagine that @WaveTheory would be be able to give you better insight. He did a rather complete review of the Jotunheim 2 and compared it to several different amplifiers including the A3.