With the upgrade to the W4S Dac2SE edition, E.J. sent me back another Dac. Not the Dac2 I previously bought. How different? Totally! The result: It is unequivocally the best decision I could make. For those of you considering the upgrade, I highly recommend it without reservation....Fresh out of the box, I heard and felt a "wow!" experience....I am hearing my music library a new.