There are a few tricks to using TV Horizontal Output Tubes, Sweep Tubes or whatever you want to call them.
First - Data Sheet Power ratings are for TV Horizontal Output use. When using in a Class AB Audio Amp the rating is much higher.
For guidance:
The horizontal output tube used commonly here in OZ was a 6DQ6A - rated at 15Watts, the tube manufacturer published recommended operating conditions when using for a Class AB Audio Amp and recommended biasing for 20 Watts dissipation. That is: the "normal" 70% of max. dissipation bias point for Class AB Audio use was 20W per tube.
Second - Triode Mode and Ultralinear Mode means that you can run screens at higher voltage than the data sheet max G2 voltage rating, because as the anode voltage pulls down then the screen voltage is reduced too.
Problem is in pentode mode when the anode voltage pulls below the screen voltage and screen current sky-rockets. In that case stick to max G2 Voltage ratings (220V for 6CB5).
As you push up the screen voltage then the required grid bias voltage increases significantly.
THis may be of interest:
http://www.ozvalveamps.org/goldentone/g ... 964rdw.gifUsing 6DQ6A for 40W Git Amp, thre was also a 60W version of this amp and 2 x 6DQ6A pushed to teh max. were capable of 85 Watts out.
Also interesting power supply configuration to generate B= and 1/2 B+ for the screen supply.
You should have no problems getting 50W per pair (100W for a quad) of 6CB5
Cheers,
Ian