3-500 and 4-400 tubes

I struggle with the fact of all that amplifier for just 600 watts. It's fun!

 

That was the "legal limit" back then.

Old amplifiers are all heavy.

 

A pair of 4-400A's in a SB-220 with the grids directly grounded will run 1200W with 120W drive and thats at about 2300VDC key down.

A tuned input is nice but not mandatory if you have a rig or tuner that can drive thru a .01 cap. It is a very non fussy tube and GG is very stable on 10-15M.

Convert the 'Bone to a big fat cap and remove the choke and you can have more fun.