Emotiva XPA DR-2 Gen 3 Amp (AB output - input H)

Class H describes the main power supply for the amp board.  It is a dual-rail design.  It will supply +/-35V voltage to the amp board as normal/idle supply.  If the audio signal raises to a certain power wattage point (probably around 200-250 watts), the input power circuit will automatically switch to higher power +/-70V power rails. 

The Class AB describes how the output transistors are biased/loaded.  It has nothing to do with the voltage/rail of the power supply.  Class AB says that the output transistors are constantly power with a set amount of watts (probably around 5-8 watts in the case of this Emotiva amp).  This means that 5-8 watts are flowing through the transistors at all time, even if there is no audio signal.

The XPA-DR amps are fully balanced/differential amp boards and require two amp boards per channel.

Thank you, I already knew the amp via spec. I saw a lot of good review and experience about this amp around the internet community. I would like to know how is audiophile community (Audiogon) grading this amp.
Pros and Cons.
As I know, this is future Amp that will replace current 100 years old transformer amp.

I have two of the XPA-DR2 amps and have also had most of the big Emotiva previous generation monoblocks.  The Gen 3 sounds okay, but it is a bit fast and bright in the upper mids and highs. The bass is also somewhat thin.  Gen 3 doesn't use fuses so you can't do fuse upgrade.  I rebuilt most of my Gen 3 amps and added in 6 x 22,000 big caps on the power supply output.  This helped with the bass, but I still think the bass isn't as full/powerful as a big linear power supply.  It also still has a bit of a upper midrange glare.  I think most of this is due to the switching power supply.  The previous generation Emotiva are great platforms to work with if you are an amp modder.  If you're looking to just buy an amp at this price level, I would look at the Monoprice Monolith amps instead.