300 Watt Tube Monoblocks

I am a fan of tube electronics, but, I don't like most high powered tube amps.  Most sound brittle and unpleasant as compared to lower powered tube amps AND as compared to good solid state amps.  If you must have that much power (I don't know of any speakers that truly need that kind of amps), look to solid state.  it will sound better at a MUCH lower price.  As yoyoyaya mentioned above, keeping a  whole lot of power tubes  running properly is an expensive proposition with a lot that can go wrong.  

How about the Audio Research Reference 330M or maybe the 750SEL if you're into overkill?

Why?

Agree with others that the cost of maintaining this many power tubes would be nuts, especially if you listen a lot or have them biased hot. You're talking some real $. Plus the insane weight and possible repairs and shipping...just a bad idea.

I would avoid this path for the reasons mentioned.  After owning some high-powered tube monoblocks and dealing with tubes melting down, the cost of tube replacement, repairs, etc. I would go solid state for amps and have the tubes in your preamp and phono stage.

One conversation that sticks in my mind is one I had with a builder of some really great tube phono stages and preamps.  I asked him why he didn't also build tube amps and his reply was "I don't want to be in the repair business".