Not sure, these are funny birds. 2 nights ago I swear there was a channel imbalance and terribly muddy sound from my Pono. The muffins was different with different players, less through better gear, but the channel imbalance remained (I listened to a high rez file off Louis and Ella which sounds great and is in mono...the right wad consistently quieter). I emailed AJ at the NY office, he asked me to send pictures, which I did (don't think they're in today, we're celebrating our ingratitude to you Brits, you know...). Didn't notice that imbalance today, but I haven't done the mono comparison yet. (Keith Jarret's recent solo concert was on, though, which should show up on a solo piano recording as well...I'm puzzled). As for testing, if they can do it in New York (and they did, and sent mine back for a rebuild), I'm sure the London home base can test too. And, the one thing I am picking up from AJ is, they really do want you to be happy. If I'm not pleased with the sound, they'll send me shipping labels to send them back to them again.