It's just my amp is sensitive. Most people have no problems with RCA tubes. It's just the bad omen I was born under.
Based on the pictures, it looks like the Sylvania tubes are very similar to RCA gray plates. But, I can't be certain. Just because they look similar doesn't mean they are the same thing. They are eerily similar, though....
P.S. Thanks for posting more pics. I'll research them more to see if they are different tubes. If they are, I'll probably buy a set. If they are the same as the RCAs, they'll just most likely make my amp hum again. Nothing against your tubes...my amp is very fastidious.
Edited by hodgjy - 12/28/11 at 5:11pm