I have the esonic-2 on my AJ-500RE. I had it to my local shop 3 times, and I sent it in to Epiphone. The local guy replaced the preamp twice. Epiphone replaced the batteries. I don't know how the first esonics are, but you can't leave the batteries in the esonic 2. They will die in a day. I emailed Epiphone's tech service probably 5 times now. You think they would have mentioned that. I still think there is a flaw in the preamp. It shouldn't chew through batteries like that. I could see if I left the cord plugged in or the tuner on, but I never did. But it does sound great playing mono or stereo.