I searched but couldn't find anything on:

Using 2 transformers
running the primary of one right off the mains
running the other transformer primary in series
with a large motor run capacitor to phase shift
the primary 90 degrees.
Rectify and filter both secondaries
Diode "OR" the rectified filtered outputs.
This would give me better than double the frequency
As the phase shift would overlap the
120 cycle pulsating DC.

Basicly I have 2 Eico 751 power supplies.
I like to beef up the supply to my Eico 753.

73
N8ZU