The RCA valves
6DJ8 (ECC88)
"RCA" (Amperex) 6DJ8 made in Holland (steel pins)
"RCA" (Siemens) 6DJ8 made in West Germany (steel pins)
6922 (E88CC)
"RCA" (Siemens) 6922 made in West Germany (gold pins)
7308 (E188CC)
"RCA" (Siemens) 7308 made in West Germany (gold pins)