Picking a Tube integrated amp

You might look at Quicksilver Audio's integrated amp. If 20 watts per channel is enough. Their amps sound really nice. They have been around for more than 30 years, and are made in the U.S. And the price is very reasonable

I’m intrigued by the Octave.  What do those who’ve recommended it like about it?  I’m thinking about the 110. Oh and by the way, I ended up selling the Vivid’s and bought the Focal Kanta No2 for speakers. My room was too big for the Vivid’s.  The Kanta is amazing. 

Not sure what the buzz is surrounding the KT 150. The question I would ask is how do they sound? Not how much power they put out.

What don't you like about your McIntosh? Why do you want to move to tubes?  The Vivid 1.5's have been characterized as clean-sounding speakers delivering masses of detail.  If you are looking to inject a little warmth by introducing tubes then the Octave may not be what you are looking for, as it has often been characterized as having a more up-front sound that is vivid.  Could be a little bright depending on your room and phono cartridge. In any case, would help to know what you are looking for when switching to a tube amp.

Another vote for the PrimaLuna Dialogue HP Integrated, I have back to backed the PL against various amps, Plinius Haetonga, Music Fidelity M6i, Vincent SP-994 with Sa-94 pre and various Yamaha amps all in my system and the PL just makes the rest sound very ordinary.
I have various sets of el34’s and the standard KT88’s but it’s the KT150’s that really make this amp sound at its best for my ears. Once you settle on what main tubes you like then you can fine tune the sound in with a couple of NOS 12au7’s, my favourite pair of 12au7’s fitted with the KT150’s at present are the LA RADIOTECHNIQUE RT 6189/12AU7WA, I also have about ten other sets of NOS 12au7's and they all make the PL sound quite different. Bang for your dollar it’s hard to go past the PrimaLuna HP Integrated in my humble opinion and the fact they are so tuneable for a relatively small amount of money is such a bonus.
I have also auditioned quiet a number of other much more expensive amps with the same Vienna Acoustic speakers that I own in various Hifi outlets in the last year and I keep coming back to the PL as it is the most pleasing amp to listen to that I have heard so far. ... Cheers Terry