I have a question for everyone, actually this is more like several questions in part. I bought the LF339 last year, but the previous owner had it for a couple of years I think. So here’s the question. I hear of upgraded version for the amp every now and then. The latest upgrade introduced non-inductive resistors which improve sound quality. 1. From my serial number, which is 03B0817, is it possible to know which version I have, and how many upgrade revisions have been applied after that, and how much sound quality improvement does that translate to? Did anyone have the opportunity to compare an old version (my version?) against the new version? 2. Is it possible to upgrade the old version of the amp to the new specifications? Thank you in advance. If someone, including yuking can shed some light on this, that would be really great.