Highest BUILD quality tube amps?


Not so much with sound...lots of ways to fine tune thru tube rolling, etc. I'm just curious which tube amps are built to last for many years with the least amount of repairs. I know Mcintosh comes to mind for longevity. I was snooping around on the web and Air Tight seems to be built like a tank and I've never read any poor repair histories. Luxman same thing. Any others come to mind?
aberyclark
I have had 3 Prima Luna integrated since 2013, upgrading each time. Currently enjoying the HP (8 KT150 tubes) and excellent headphone amp. Never had any problem, despite the heavy use. 
Do they have to be good sounding amplifiers or just well built? Should they be really heavy? 
No mention yet of Thomas Mayer? Ok he is in Germany and not well known in the US. But if build quality is the question, then his work must be included. Every aspect is of the very highest quality down to all solid silver hand wiring. Yes they sound great too.

Not only does he design and hand build his amps, he also makes his own TUBES! Which of these others do that?
I have 3 pair of Quicksilver mono amps and they are super reliable, never had a problem plus they are very musical. Since I have them I forgot about all of my audiophile manias and now I simply enjoy music...