FiiO A5 upgraded!!! I change MUSES02 to OPA 2227P from BB. Now A5 sounded ammazing! OPA 2227P have on this circuit PCB better sound than MUSES02. I tryed OPA 2228 P (BB) and it is great too, but not more musician than OPA 2227P. Now A5 have better soundstage (wider), and have more details...