Pass labs xa25 amp and BW 804 d3?

Sorry man, but that DK doesn't come close the the quality of any Pass amp. If you're talking about the one Stereophile reviewed, that's a product of numerous dubious design choices. The XA25 is a vastly superior product. 

Dear Readers;
I run my Vandersteen Model 5s with a Pass Labs X250.  The x250 has never left class A operation as indicated by the front panel meter.  The sound level if desired, can be quite high.  Maybe not rock concert level, but very adequate for home use.  Hope this helps.

How many class A watts does  the Pass Labs x250 provide? 
Charles 

The X250 isn’t even a class A amp. It’s a high bias class AB amp with a single ended bias of 20 watts. 
Contrast that with the XA25 with it’s 50 watt class A envelope. That’s a plenty of amp for most people.

https://www.passdiy.com/project/articles/leaving-class-a

Macguy said his meter indicates the amplifier remains in "class A operation". So the first 20 watts of the x250 is bias in class A (bias set  at 0.8 for this model per the Nelson Pass article). At his listening levels the Vandersteen speakers aren’t demanding of more than these first 20 watts. I suspect that very often not more than a few watts are utilized at easonable listening levels.
Charles