Your 6550 WE PS regulator is definitely ready for replacement. The (4) 6H30s are still good to go. I'm not a tube roller, but other may have some suggestions. Enjoy.
The "old" 6550 "Winged C" tube was what ARC used to use in the Ref 5. I understand that the factory that made the original 6550 Winged C burned down several years ago. One vendor who sells 6550 Winged Cs cancelled an order a while ago because of quality issues.
Call Kevin Deal at Upscale Audio. He'll steer you in the right direction.
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