Sylvania 6SN7A 6SN7GT Metal Base Black T Plates 2 Hole TV7&Maxi Test NOS. Top of the Tube is stamped 6SN7A and metal base says 6SN7GT. Tests strong NOS with nice shiny getters. Confirmed NOS reading also on my 539C tester.

Tested per user manual procedures on TV-7D/U recently calibrated by Dan Nelson (TV-7D/U calibration expert) (Documentation available upon request)

Passed all tests:

Shorts Tests: Passed

Mutual Conductance (GM)Test: 104 & 94 (77 = NOS Average & 50 = Good MINIMUM)

Gas (Grid Current)Test: Passed

Maxi-Preamp 2 tester results:

Tested noise (< 92 DB): Passed

Gain: (18.4 and 16.2) MU

Also tested in THD Guitar amp for performance and sound at operating voltage.

For the most reliable and comparable results, I try to test using both vintage and modern test equipment along with testing in amps when possible. Test results will vary between testers as it is not an exact science. I also use variac at 120 volts with my testers.

I recommend all vintage tube pins to be cleaned before usage for best performance.

Will combine shipping. I will send refund promptly once actual shipping cost is determined.

Given the fragile nature of tubes, they will be securely packaged for shipping. Please notify me of any issue or concerns once you receive the items so I can promptly address. Guaranteed not to be dead on arrival.

I have been on eBay for over 20 years.