[morzh]

Well....the 12AT6 came last week and the 50B5 came today, after, according o the seller, having first returned back for invalid address.
To add to that, the tube was supposed to be a Philco.

That one.

http://www.ebay.com/itm/262788004817?_tr...EBIDX%3AIT

If you look, this below is the same photo, but says the different tube.

http://www.ebay.com/itm/Philco-6S4A-Elec...2788004817

In fact he has bunch of Philc tubes listed with the same exact photo.


What came is an RCA in the RCA box. I am not even sure the glass marking is the same in the picturre.
But it is a 50B5 and tests as it should.

Anyway, the hum diminishes just a smidge after changing 12AT6 and I am not even sure it is not a wishful thinking at play.
Went through the chassis....no non-conformances present.
I decided to throw in the towel. It works, with that resistor decreasedbit doesn't hum too bad, so....