so...caps are done,back in the can on the topside of the chassis where they belong...tho with no change to the buzz...i guess it was mostly unnecessary but it does free up some fairly tight real estate under the chassis,and my sense of aesthetics likes this cleaner "hidden" setup much better.
i also got to borrow a friends tube tester over the weekend and ran all the tubes through...surprisingly most test as new,of the three 12ba6's the lowest came in at 98%,the RCA 50L6 bounced off 100% and then pinned the needle down hard...she's a good'un! the 12at7 and 19t8 were less thrilling testing at around 75% each,but the tester's owner tells me those readings are quite good for those types on his tester,he didn't think he had any that tested much better in his surplus inventory...so the tubes are good to at least quite serviceable..
i started to change out a few moderately drifted resistors around the output tube socket,and took the opportunity of doing the caps and having a few other things disconnected to reroute and clean up some wiring...which seems to have reduced the buzz by about half..it's not quite gone yet but it's significant progress!!! i think i need to do something more with the diode/resistor rectifier combo as these are still mostly just in a temporary/testing config at the moment,but i suspect that's the actual noise source,the cleanup has not so much moved any lines farther from each other or closer to the chassis...but has tucked them up farther away from the rectifier...I'm not sure that that's the key to this, but I'm happy just to have made any progress in the right direction!
and the adventure continues...