Ever since I started building tube amplifiers, the 211 was among my favorite tubes. In fact the very first power amp which I built used the 211 as an output tube. This first amp evolved through several stages and finally ended up in huge monoblocks with 211 drivers and even bigger 3 phase power supplies. Those of you who are familiar with the Sound Practices magazine might have read my articles about this amp and the 3 phase power supplies.
After I started to go commercial with my amplifier designs, I decided to build a scaled down version of this amp. It used a single phase supply, and a smaller but still directly heated driver, the 801A. Power supplies were still external so that the whole amplifer ended up in 4 chassis and has a weight of more than 100kg.
This is a photo of one channel of the amp: