Hi, my 4-year old 5E3 Tweed Deluxe clone amp blew the power (mains) transformer, I just replaced it yesterday. According to the amp builder possible causes to the transformer failure could be either bad quality (inMADout TA84M18, handmade in Italy) or a faulty rectifier tube. My amp had been acting strangely for awhile after a 'proper' warm-up, usually during gigs, occasionally at band rehearsals, but never at home. And I had been using an (allegedly) NOS Sylvania JAN 5Y3WGTA from 1966 for just about two years, maybe 3-4 hours hours weekly, which is not that much? So, maybe I ought to replace the rectifier tube just to be sure, and I'd like it to be a true NOS tube, not something that somebody had found in the trash can. Ebay offers this and that, but what I'd like to have are recommendations for a good tube from a reliable seller. Help, please?