Identical codes. Tubes carefully tested for transconductance, shorts, gas, life and leakage. No tube is sold that has any gas, leakage or fails life and strength tests. Hitachi NOS 6SN7GTB Vacuum Tubes.
Two, Tung Sol 6SN7GTB tubes. Opposing black plates, TALL bottle D-getter. The 6SN7GTB can be used in all applications calling for the 6SN7GT and 6SN7GTA. Firm bases, excellent silvering. Tubes are matched for dynamic gain and structure, testing at 2875-2750 and 2750-2750 where pass/fail is 1625 micromho.
Where 50 ( μ) is Good these tubes peg at 73/77 for Emission. Where 2,600 (ma/V ) is Good these tubes peg at 3,000/3,100 for Mutual Conductance. Mutual Conductance: The 750 is a dynamic mutual conductance tester.
This tester also is used in conjunction with a variac to maintain test results accuracy and consistency. Average new tube value 76/76. Tube test Value - 80/82. Minimum tube value - 50/50.
Tube 1 Emissions 91% & 86% | GM 100% & 96%. Tube 2 Emissions 83% & 86% | GM 100% & 96%.