For sale 6sl7 tube nos Fivre Italy brown base same code same old production 186 code
brown base
fat plate
smooth plate black anode
square getter bottom
full mica on top, clear top
Old production 1940's
Made in Italy
original vintage vacuum tubes preamp
pre amplifier tubes
2x tubes pair
TV7 test results
tube 1 = 53/52 (reference good at 32/32) code 110
tube 2 = 52/48 (reference good at 32/32) code 110
both tubes identical inner structure, from the same lot , same factory code 186
box 194