5U4GB TAD PREMIUM SELECTED straight bottle

5U4GB TAD PREMIUM SELECTED straight bottle The Straight One! The 5U4GB has a straight glass envelope. This type has been widely used in U.S-made guitar amps from the 1950s to the 70s. The 5U4GB has a slow start feature, which protects output tubes from high voltage peaks when you switch the power on. Q: When does a tube become a Premium Selected tube? A: All tubes labeled Premium Selected have passed the following tests: - Plate Current (PC) and Amplification (TC) - Low Noise Test - Microphonic Test - Sonic Tests - Shock Tests - Listening Tests - Shorts & Leakage Tests TAD Premium Selected tubes are guaranteed for a period of 6 months (according to terms of warranties) for the quality criteria mentioned above.