[Doug Houston]

As far as I know, the 37-650 was the first Philco model to use that goofy phase inversion. I too, couldn't figure out how Philco got inversion. I was in my first year of high school, and a smarter kid than I, explained it.

The "screen inverter" was used by Philco for loads of sets for all of those years. I'm currerntly working on a '39 Packard-Philco set with P-P 41 tubes, and there it is; our favorite phase inverter!

I must say that for all of the years that our family had the 37-650 that father bought new for Chistmas 1936, the set worked perfectly, and sounded very good to all of us. Today, the sound system in my living room is a tad more sophisticated, but what might one expect?

Also, as far as I know, Hazeltine Corporation did Philco's circuit engineering, so I suspect that this inverter is one of their wrinkles. You have to admit...it's tricky, but it works!