Picking a Tube integrated amp

Another vote for the Rogue Audio Cronus 2...I’ve found that the additional power has substantially improved the lower mid and midrange dynamics of the music I hear through my system with fairly demanding speakers (Vandersteens). It’s not about volume but rather dynamics...

The Melody MK 88 is a sweet little amplifier. 

https://www.angelcityaudio.com/products/melody-valve-hifi/mk88/

As well as the Astor Black 50 

PrimaLuna HP with KT 150 tubes in ultralinear mode puts out almost 100W.
Drives my Revel F206 (88dB sensitivity) no problem even in triode mode.
Haven't tried other suggested amps, but pretty happy with the PL. Especially with Mullard CV4003 and KT150s. :)

Completely rebuilt Sansui 1000a. You’ll have 1100 into it and the sound is sublime. It blows my rogue away. The famous old Sansui iron is as good or better than today’s transformers. The level of detail and the amount of low end punch is stunning. 

I had the AR VSi60 and it was a very good amp. I used it with more sensitive speakers, but I think it would be enough to power your vivids. My one nitpick is that the gradation of volume steps at low levels was not fine enough and I struggled with listening at low levels. So late night listening or having music on in the background with people over was not great. But when the timing was right for me to kick up the volume a few notches, it was clear and detailed and yet magically tubey.

If it's in your budget, take a look at the AR VSi75. More power (and more control if you're listening at low levels) and an upgraded volume control that is much finer than its little brother. 

The amp sings. Plus, it's made here in the US and customer service is pretty solid.