I’ll add my 2 cents.
After researching for tube amps for a significant time, I settled on the 845 compact. Regardless of which tubes used, Mastersound is a quality amp manufacture in build and sound quality.
I agree with Chayro that Mastersound amps are not “tubby.” Depending on speakers, I found the sound natural and excellent performer for the amount of class A power provided. Sit back, relax, and listen.
I bought my mine used, For my price range, my model outshines many competitors. After being the solid state domain for a long time, I transition to the tube world, and considered McIntosh C8 and Audio Research I-50 models ($4k range).
The appeal of the Italian old school handcrafting, their methodology winding of the transformers, single point architecture, and blend of wood elements are some of the reasons why I went with Mastersound compared to the models listed. Tube rolling may further improves your sound outcome and system integration knowledge.
I will say, you will not disappointed with the Dueventi model. Enjoy.