[R-390] 6C4 variations

[Perry Sandeen]

Hello List
 A quote from the service manual said:
"The differences in characteristics are suchthat the type 6C4W will not operate properly in the receiver." <snip>
While the original author is unknown, this is totally inaccurate.
"Some capacitance values are different"  Maybe. The tube manuals a  .1 to .2 pF differences in their listing of interelectrode values. Well within a margin of error but still irrelevant at B/A frequencies. 

I did a search in both my different RCA tube manuals as well as three or four more online,  I also consulted the "Tube Substitution Hand Book" by Smith and Buchanan which lists all 6C4 variants as the same for any use.
The same was also true for all the tube manuals I viewed.
There was no mention any where of 6C4 differences.
Igror , get the torches, wooden stake(s) and garlic.
Regards,
Perrier