I am also looking for that GR07 upgrade and based on Cotnijoe's review, the 3.Ai sounds like a good possibility. So being one of those few who have the Hisoundaudio Studio V, I contacted "the wizard" aka Fullcircle, to get the sensitivity of the 3.A and he said Heir doesn't "give out specs to the public."
I'm currently watching for the old "Twin Peaks" series which is all about secrets, so when I got his response I wondered "why the secret?" Unique Melody gives out their "secret" specifications as do many other custom manufacturers. I don't hear hiss with my GR07's, but when I had the JH5's there was hiss galore even in the mode for high sensitivity armatures. The JH5 sensitivity is 119 and 105 for the GR07. I'm kinda stuck with my expensive player to around 105 to 110 db which is good for dynamics, but makes IEMs with armatures a dicy proposition. Just don't like my Ipod or Hifiman 601SQ as much as the V and don't want to have to buy a new player. If I don't get the 3.A due to my "hissy problem" I'm hoping the GR08 will have a low sensitivity.
Edited by soundbear - 8/20/12 at 10:44am