Any US manufacturer of a 845 SET amplifier

I dont think that Kara (DeHavilland) is still active in this market. Perhaps I am wrong but I think this is worth mentioning.

i remember my cary 805’s... massive, lovely amps with such a warm luscious sound! couldn’t drive my proacs at the time on more dynamic music in a large listening room at the time, was sorry to see them go

Coincident Technology makes a limited edition 845 amplifier. They’re a Toronto company. I think very highly of their Frankenstein momblocks, which are 300B. Those guys know their tubes.

From the reviews I read, it sounds almost as good as an Audio Research 6550 amp.  They are made in the USA I think...

Cheers!

Are you looking for an amp or integrated amp?

Cary Audio makes an 845 based amp --  

https://www.caryaudio.com/products/cad-805rs/

And Line Magnetic makes both 845 integrateds (845ia and 845Premium), and amps (503PA and 513PA).

I'm a dealer for both lines.

And we generally do not see issues with Line Magnetic.  But if you do, there's a service facility for everything that Tone Imports brings in here in the US for repair.