Highest BUILD quality tube amps?

I have had my Marantz 8b since I bought it in 1964. I also bought the reissue in the 90s. Still working just fine, bother of them. Glorious.

Line Magnetic and Finale Audio, good quality and sound at reasonable pricing

I really want to save for a new MC275. It has the looks and I like the sound. However, for less money, I can get monoblocks (which I prefer) from Quicksilver or Primaluna. I just wished the QS's looked more pleasing (I know that is weak..but I do like good looking equipment as well). The PrimaLunas look nice, I just wished they were built over here, japan or Europe (I know if they were, the price would be much higher). I was an automotive manufacturing manager and we had so many quality issues with cheaper asian built components (China, etc) that has left me hesitant (yes, I know my phone, TV etc were built there). 

Interestingly, I have had more problems with US made equipment. Not so much with gear made elsewhere in other countries. In fact I had US made audio made by a German guy that was dreadful and poor parts. But my Chinese made gear was made great and the customer service top notch. If one is selective, great gear can be purchased from China and elsewhere.

Hand wiring in a tube amp is a good idea. In tube amps with higher voltages, its possible for an output tube to create flyback voltages between the plate and cathode connections. This can cause arcing on the tube socket and if mounted on a circuit board, arcing on the board too. Flyback voltages can occur when the amp is driven into clipping and an output tube is driven into cutoff- at this point the magnetic field in the output transformer collapses and creates a very high voltage- similar to how a spark coil works in a car.


If the amp is hand-wired, sockets are much easier to replace! If there is a circuit board that is damaged by arcing, it can be tricky to repair.


The other issue of circuit boards is heat. Power tubes run hot and this can degrade the circuit board over time. This can be particularly problematic in tropical environments, where its a good idea for the circuit board to have what is known as a 'conformal coating' which prevents corrosion.


Finally, the design and quality of the traces and pads of the circuit board can have a big effect on how repairable the board is- a poorly designed pad (as seen in 1980s ARC) does not survive component replacement very well. So if a circuit board is employed in tube equipment for best longevity it should be 1/8" thick with the heaviest traces, employing a conformal coating, with good pad design and ample cooling holes around any components that run hot.