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ARC D-75A Regulator tube

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Hey all, I have a D-75A amp, and the regulator tube (6550) seems to have flaked out...I have a 6L6GC that I am thinking of using, as the D-75 amp schematic has a 6l6GC instead of the 6550 for the regulator tube.

Looking at both schematics for the D-75 and D-75A, they both show the same 575v on the plates of the regulator tube, but the max plate voltage is 500v for the 6l6GC...

Any issues in using it as the regulator tube? I don;t think the current through this regulator tube is very high...
 
While the 6550 is an all around better tube for the most partr, a 6L6GC will work ok. Remember that the cathode will be elevated and there will be a lot less then 500 volts across the tube. And lots of old style tube regulated power supplies like those of Lambda, Fluke and even Kepco used 6L6's as series pass tubes without issue.
 
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