Carlitos, I don't know who you're talking to but yeah I have fixed it as I had that problem with EF80 with vanilla 339. The problem was the wiring in the adapter. There was a bad solder to the metal enclosure of the adapter with the ground connector in the adapter, bad solder joint spotted with a ohmmeter. It's hard to solder against solid thich aluminium without solder flux a,d scrapping the surface. You need a strong iron too.
Anyway I made mods to my amp with battery cell for imput bias and at the voltage I'm running the EF80 are no more suitable for me. All my other imputs tubes sounds great though with my adapters (Pentodes strapped and pure triodes types)