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Engraved Base National Union NU Type 45 ST Bottle Dark Plate Tube 539C Tested ANOS.
Tested per user manual procedures on Hickok 539C recently calibrated and upgraded to digital gauges for improved accuracy by Hickok Meters (539 calibration expert) (Documentation available upon request)
Passed all tests:
Shorts Tests: Passed
Mutual Conductance (GM)Test: 58.7 (60 = NOS AVERAGE & 39 = Good MINIMUM)
Gas (Grid Current)Test: Passed
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 and all testers have their limitations.
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 for over 20 years. Been collecting guitars, vintage amps and tubes for over 30 years as a hobby.
