RCA etc. ONE (1) 6BL7GT tNOS AT1000 TESTED Vacuum Tube Tall Boy Dual Triode 6BL7 1950-1968

This listing is for one (1) 6BL7GT Dual Triode 6BL7 vacuum tube in the straight-walled glass tube shape. It has a black bakelite octal base, black plate, and top square or halo getter. Labels in stock include RCA, Ken-Rad, CBS, GE, Sylvania, Westinghouse. Some of our stock is re-labeled or marked with the OEM of Muntz, Zenith, Philco, Reliatron. If you're looking for a particular brand, please message right as you order - we pack and ship quickly!

Your tube has been fully tested on a computer-regulated, USA-made Amplitrex AT1000 on Fixed Bias setting with like new, NOS results (tNOS). Here's what that means: to qualify for this listing, several stringent conditions must be met: The transconductance for each section must measure between 5600 uMhos and 8400 uMhos, consistent with original 1950 RCA, Western Electric, Sylvania, GE, and/or Tung-Sol datasheet specifications for new tubes of this type. The tube must also show no shorts, show a gas current less than 4 mA, and a heater-to-cathode leakage of less than 10 microamps (10 uA). The tube might have mechanical wear or have the label rubbed off - these are very old! Used-testing tubes are available in a separate listing at a significant discount. Every tNOS or Used Good tube you receive from Sound By Doc is guaranteed against failure for 60 days after purchase, an industry extreme!

OPTIONS (use offer feature in Reverb):

Want a regular white box? $1 extra per tube
Want a tube that's packed in its original box? $3 extra per tube
Want the test results recorded on your box, too? $3 extra per tube