This seems redundant with what has been said. It is from head-fi.org. "Originally Posted by kiertijai
Here is the description of that Tesla 6SN7 or 6CC110 (google translate from Japanese to English)
unused 6CC10 of TESLA still have not seen at auction overseas, is an exhibition of the same Rottopea. TESLA is the age between 1940-50, there was a vacuum tube system compatible with two types of 6SN7. 6CC1 is a compatible product before and after 1950, until the end stage is 6CC10 from mid-1950s, is almost the same structurally.
The official name of this tube is 6CC10, was manufactured in the plant is the main factory ROZNOV of TESLA. No. 6CC10 is still called, is present in the vacuum tube system Number of Russian-made 6SN7, 6CC10 now is almost the same as 6N8S (6H8C) of so-called Eastern Europe Part structurally. Contents of this tube, and they are quite different, is a super super scarce goods deserve to be called a prototype of the structure of the original 6CC1 or 6CC10 this TESLA. The structure of this pre-tube has been very very similar to 5692, represented by the RCA, this support of five thick rod support spring spacers suppress the vibration plate with a small rib of length 25mm, at the top of mica, the mica sheets 3, It has characteristics such as the square getter in the top two. Vacuum tube with a similar structure that are essentially two types of 33S30B 5692, SWEDEN of RCA, of ERICSSON, or imitation or by chance, camp three major Western Europe, Scandinavia and Eastern Europe 1950 to the same vacuum tube system 6SN7 same concept happens to will be had to. Moreover, these three species has been manufacturing equipment for the military only as a radar tube and all. It was built is 5692 for RCA is 1951 By the way, because is the midst of the Cold War, there was a technology licensing from RCA were not considered to flow into Eastern Europe is 33S30B of ERICSSON of SWEDEN has received technical assistance of RCA probably I think that would be more natural to think of Te have been copied. This pair is old-fashioned look, the print has a half-moon-shaped country of MADE IN CZECHOSLOVAKIA under the print than all your left firmly, TESLA, that 6CC1. Is illegible, but apparently there is a production lot number on the opposite side of the glass. AT1000 vacuum tube as measured by the latest digital measuring instrument, of Amplitrex, the plate voltage is 250V, = 9.0mA expected value Em, = 2.6mA expected value of Gm for (2600mmhos), each pole, Em = 9.6mA 6 #, numeric value greater than the expected value also say Em = 9.6mA, and Gm = 3.4mA each pole, Em = 9.4mA, and Gm = 3.0mA, Em = 11.5mA, Gm = 3.4mA, and the # 8 Gm = 3.2mA, Because to achieve, we have determined that an unused item. 0.0μA leakage poles, gas is # 6 = 0.2-0.2mA, is 8 = 0.4-0.4mA #, 10mA are significantly below the allowable value of the approximate gas tube GT. Bulk goods for military use."