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:
Tango interstage and output transformers, NOS paper in oil caps in the power supply. DC heating for both driver and output tube using a purely passive LCL filter per tube. The sound of this amp is excellent and very close to that of the bigger one with 211 driver. The amp was publicly demonstrated at the ETF 2009 in Stella, France. Yet for many the sheer size of this amp with 4 chassis in total is a bit overwhelming. Here is a photo of the complete set:
The 4 chassis in the front row are just one stereo amp!