08-22-2015, 07:56 PM
Thanks for the suggestions Mondial
My 7A8 tested at 96/100 on my tester, but I realize that mixer tubes can be very finicky. Unfortunately, I don't have a spare in stock, so I will have to order one. In the meantime I'll try freezing that 47pf cap and replacing it if it is affected by the temp change.
Now that I think about it, those small value caps were usually mica weren't they? I wonder if a previous owner replaced the original cap with a cap that had a different temperature coefficient than the original. If so, that might be the cause of the problem. Sound reasonable?
My 7A8 tested at 96/100 on my tester, but I realize that mixer tubes can be very finicky. Unfortunately, I don't have a spare in stock, so I will have to order one. In the meantime I'll try freezing that 47pf cap and replacing it if it is affected by the temp change.
Now that I think about it, those small value caps were usually mica weren't they? I wonder if a previous owner replaced the original cap with a cap that had a different temperature coefficient than the original. If so, that might be the cause of the problem. Sound reasonable?
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