[Amps] Anyone recognize this amp / circuit?

[Mark Beckwith]

I have acquired a homebrew amp as follows:

It has two 4-400s in parallel in grounded grid (with a hole for a third one, 
FWIW).  The bandswitch has positions 80-40-20-15.  It has TWO 30A Filament 
transformers with 110V primaries wired in series with the outputs in 
parallel.  Input is not tuned.

HV power supply is separate, outboard.

This seems like something I might have seen in an old handbook?  Does it 
ring a bell for anyone in this group?

Fun project.  Any conjecture about how I would fare adding 160, 15 and 10 
meters?

Thanks in advance for any posts in response.

73 - Mark, N5OT