| Qty 1 of Sheldon 6S78 tube NOS NIB, which is a hand-selected RCA-made 6SN7GT featuring design of wide black plates, clear top, bottom large rectangular-D getter. Both triode sections tested very strong and good balance (3600 / 3300 micromhos) on my professionally calibrated Western Electric (advanced version Hickok 539B) mutual conductance tube tester, and without shorts or leakage. Scores above 1700 are good. Photos show each triode section being tested (6000 micromhos scale) |
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