Eddie

If the transformer output is floating, like driving a headphone, it is a perfectly balanced line. Since we are talking about the balanced output, how the signal gets there can be as simple as an unbalanced line driving a transformer. In the case of the 307A, the 307a is run SE with the transformer as the plate load. Looking at the 307a it is running with an unbalanced input, and true balanced output. Running two solid-state amps to get a balanced line can never be as accurate because the amps have to be perfectly matched, and each amplifier will still present a reference to the power supply rails, where the transformer output is isolated from grounds, or grounds through the power supply. My two cents best sound at the Florida meet.

Yes following the release of the EC Down Converter this Month, I am building Five Zana Deux's. They will be built on an aluminum chassis with aluminum top and bottom plates. The power transformer will be on top, but with a matching cover. It will be flanked by two vacuum tube damper diodes. The power supply will use three low esr inductors and four paper/polyprop with soy bean oil caps. The circuit is the same as the proto otherwise. Pre production hopefully by the end of April. Price for the first, and maybe the only five will be $1790.00.

I responded to the tube socket issue in another post, but in a nut shell. The Zana Deux does not operate the 6C33C-B anywhere near its max rated power. In fact only about 8 watts on the plate. Even with the heater current figured in the total heat from the tube, most of which is dissapated in the air, is about 43 watts. The production ZD has the tube sockets fastened to a thick aluminum top plate which also sinks heat away. The original Xana has been in service for years and I have never seen a socket failure.

Late to the party, but I would like to respond to statement about the 6C33C-B eating tube sockets. That depends on hard you are slamming the tubes, and how the socket is mounted. In the case of the Zana Deux the 6C33C-B is operated at only 8 watts of plate, and the production amp will have the socket mounted to an aluminum top plate. The original Xana was built this way and have been in constant service for over 8 years without any socket failure. The key to the Zana Deux uis the low source out, 12 ohms, and ability to couple all those power supply joules directly to the load. Also less is best, why put your signal through so much stuff when two tubes will do the job.