01-02-2016, 02:40 AM
Yes, tube shields are necessary, at least with the 6Q7G, but thankfully if it is a 37-665 they used the tube shield bases that allow the use of a metal or a GT style tube in place of the G style tubes, a 38-665 would not. Yes, you can use Soviet/Russian tubes, as long as they are electrically the same as the North American type, but other then the power tubes most of their octal types were metal so there really is no price advantage in using Soviet/Russian octals.
What makes you think that the output tubes were bad? If there is high distortion that's usually indicative of a biasing problem, not poor emissions. A power output tube could be gassy however, at that could cause distortion if they work at all. I would get a 6J5 if that's what the set calls for and the 6C5 is no good, the 6C5 is not an exact match to a 6J5 though it may still work in some circumstances.
Regards
Arran
What makes you think that the output tubes were bad? If there is high distortion that's usually indicative of a biasing problem, not poor emissions. A power output tube could be gassy however, at that could cause distortion if they work at all. I would get a 6J5 if that's what the set calls for and the 6C5 is no good, the 6C5 is not an exact match to a 6J5 though it may still work in some circumstances.
Regards
Arran