12bh7 tube black plate Marconi Italy square getter welded 1950's preamp tubes 1x single tube
one tube 12bh7 Marconi made in Italy
black fat plates
squre getter welded
old production 1950's
tested twice
test results on tube tester TV7D/U = 46 & 46 (reference good at 30 & 30)
tested also on tube tester Funke W19s Ia(mA) = 15mA & 16mA (reference goos at 9mA & 9mA)
very rare tube preamp, one piece = one single tube original vintage made in Italy