I certainly understand the concept and effect of "burn-in".For the past 30 years I've had Naim equipment as my home listening audio,it takes months of "burn in" to arrive at optimum performance.Every pair of headphones/earphones I have required "burn-in",the sound signature always changing for the better.
With the Dragonfly,I had stopped using the v 1.0 with my Senn.650s,simply because I found the sound too shrill.The DF sounded fine with Senn. ie80s,largely because of the olive tips which slightly muffled the sound,the combo worked well.I don't recall the v 1.0 changing at all with "burn-in".The 650s entered into the equation after the ie80s,hence my quest for a better combination.
I have been listening constantly with the v 1.2 for the past 2/3 days,using mainly the 650s,but testing the ie80s also.The new version is leaps and bounds ahead of the v 1.0.! It is,as advertised,a great deal smoother,airier,and somehow,reveals previously unheard of details in tracks I've been listening to for years.My test CD has been,Tony Williams Lifetime "Believe It".A lot of "splashy" drumming and fusion guitar.With the v 1.0 it would be verging on painful to listen to,with the v 1.2 it's bliss.Placebo?,I don't think so!
I hope the v 1.2 doesn't "burn-in",or if it does, it improves in some way,although I can't think how it might.The whole deal with audio listening is entirely subjective.I do know that to my ears the v 1.2 sounds fantastic.
Kind regards and Seasons Greetings,Cenacheros.