Comparison of RCA tube type input transformers used in broadcast and theater equipment from 1933-1967. Cases and sizes compared with UTC LS, HA, and A types in the background for comparison. There are of course a few others; for instance 1940's Hollywood Photophone production used Hollytran square can iron, in many cases with the same part #s as the broadcast stuff. There's also some square cased transformers pre-1933. This is effectively representative of everything they used in broadcast audio during these years. The PA/industrial line type is thrown n as another example, and seen on the lower end non-broadcast stuff, as are some novar socketed plug-in types.
Case types, left to right: 1933-41, 1937-41 (DeLuxe line), 1938-57 (2 pieces of differing sizes, program amp and preamp, representative of BA-3A and BA-1A among others), 1945-50 (OP-6), 1945-approx. 1956 (PA/industrial lines), 1954-1967 (BA-21A and BC-3/5/6 consoles). UTC LS, HA, and A in background of two pics.
The first one weighs 10 lbs, and is encased in 1/2" solid copper shielding. You can get 1/2" scale by comparing the thickness of the top on it.
Only the last two shown are UTC, with the PA type also having been previously available in RCA winding.
Case types, left to right: 1933-41, 1937-41 (DeLuxe line), 1938-57 (2 pieces of differing sizes, program amp and preamp, representative of BA-3A and BA-1A among others), 1945-50 (OP-6), 1945-approx. 1956 (PA/industrial lines), 1954-1967 (BA-21A and BC-3/5/6 consoles). UTC LS, HA, and A in background of two pics.
The first one weighs 10 lbs, and is encased in 1/2" solid copper shielding. You can get 1/2" scale by comparing the thickness of the top on it.
Only the last two shown are UTC, with the PA type also having been previously available in RCA winding.
