How many watts do you need?? What is your speaker sensitivity??
This 845 amp is 110W in the title, possible pushpull circuit, this is not upgrade in quality.
The best sound tubes amps are Single Ended, low power(300B), but some like 2A3 and 45 for even lower power and hi sensitivity one way, fullrange speakers.
But I like SE amps with the 6C33, GM70 and 805(with a impressive gain of 50 times).
211 has medium gain(12) and yet sound refinated but not great as the 805, and the 845 has a low gain(6) and is the ugly duck in the mid range.
On this same brand there is this nice 805 amp to 50W=hi power for a SET, with 30W and a 100dB speaker it will sound better and the 805 tube will lasts years.
http://www.iconaudio.com/portfolio-item/mb-805/A 50W 805 amp with a Chinese tube(125W plate) will lasts few hours, for longer tube life one must low down the power in the Bias to 30W, if it is manual Bias(before consult the manufacturer about it).
Some current 211/845 tubes are no more 100W plate, but only 75W plate, but the amps for these tubes are intended use tubes with 100W plates.
Other nice amp in this Icon brand:
http://www.iconaudio.com/portfolio-item/mb-30se-mono-blocks/16W in SET w/ KT120, a inexpensive tube.
