Buddy of mine down here in South Africa, JP Le Roux, famous boutique tube amp builder, came up with this amazing 6V6 20watt poweramp built into the Kemper Head.
Has a silent fan that handles any kind of heating problem, sounds amazing!
Before the guitarist engineering scientists start debating whether the Kemper needs a tube poweramp or not, :), it is what it is, if someone down here who owns an unpowered head wants a tube poweramp then they can get it.
Of course I still push the Powerhead or PowerRack to my customers.