Bigger and Better: Integrated Amplifiers

For our collective entertainment, this thread is all about upgrades.  The rule is that you cannot post unless you have owned the most recently posted integrated amplifier and upgraded to a different integrated amplifier.  

For example, I started with a Yaqin MC-30L and upgraded to a Pathos Classic One MkIII.

The next person should post their upgrade from a Pathos Classic One and so on.