03-07-2015, 12:48 PM
It really does look like that radio was a prototype or pre-production sample.
Even the metal chassis seems to be modified. If you look closely at the photos it appears that the holes for two tube sockets were punched and then filled in again, with tiny spot welds retaining the filler slugs.
I think you are right regarding the Sprague caps and the "S" suffix. I believe the ones with no suffix are Cornell-Dubilier caps. They owned the patent 1,900,093 which appears on all of them and must have also licensed the patent to Sprague.
Even the metal chassis seems to be modified. If you look closely at the photos it appears that the holes for two tube sockets were punched and then filled in again, with tiny spot welds retaining the filler slugs.
I think you are right regarding the Sprague caps and the "S" suffix. I believe the ones with no suffix are Cornell-Dubilier caps. They owned the patent 1,900,093 which appears on all of them and must have also licensed the patent to Sprague.
![[-]](https://philcoradio.com/phorum/images/bootbb/collapse.png "[-]")
