Mike wrote: >>>>>> How about a pair of 4-400As ... Yes, the Eimac 4-400A is a good tube. Still running at full output after 54 years, with the original tubes: http://www.zianet.com/k5am/amps/6mkw.html Input for full output: 8 watts. Output: 1200 watts, using the original 1961 Eimac tubes. 73, Mark, K5AM