IMHO a Berning ZH270 will blow your mind, and you can use it as an integrated as it has a passive pot built in.

Frankly, I still find it shocking just how good this thing is compared with the oft touted alternatives. It has all the advantages of valves with none of the drawbacks. Bass like a PWM switcher and valve life 10 times the norm - and it rocks like a good 'un.

My previous amp is regarded as superior in many ways to £12K Audio Research seperates and easily saw off some expensive US 300B monos with WE tubes along with other valve offerings from Audion and BP. The Berning makes it's predecessor sound broken.