RCA 6l6GC Tubes


I recently found some RCA 6L6GC tubes. They are labeled 6L6GC and USA on the glass and have the black base with red RCA logo, but the top is silver not clear like all other RCA Blackplate 6L6 GC's I have seen.

Are these RCA Blackplates? Maybe later versions?

     -GAR
gareents
RCAs will always have the "stop sign" logo around the 6L6GC designation. However I can think of at least 3 perhaps 4 different internal constructions with the RCA black plates. If you post a photo I can tell you who actually made your tubes.