I spent a whole day comparing the original Metrum octave with separate power supply to the AN 2.1 Signature DAC. Given it cost 3.5 times the Metrum, I much preferred the latter, it really is a giant killer providing it is used with a properly specified coax cable.
On the other subject of Metrum products, I am sure they are good sounding for the money, but have been bested by other
products in the OS ranges. I wonder if they would sound better than my DAC 3.1 with trick parts? The parts in the Metrum look
a bit cheap? At the end of the day, if the design is good, it comes down to part quality and tube selections. And of course the
all important power supply. If it sounds better with an Audio Note Trans, maybe you should just get an Audio Note DAC?