RCA etc. Pair (2) Type 39/44 Antique tNOS AT1000 TESTED Vacuum Tubes Pentode 1935-1949

This listing is for a Pair (2) of Type 39/44 Pentode Antique vacuum tubes in the ST (Coke bottle) tube shape. They have a Black 5-pin base, nickel mesh plate, and bottom foil getter. Labels in stock include RCA, Tung-Sol, Philco. Some of our stock is re-labeled or marked with the OEM of Motorola. If you're looking for a particular brand, please message right as you order - we pack and ship quickly!

Your tubes have 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 800 uMhos and 1200 uMhos, consistent with original 1935 RCA, Western Electric, Sylvania, GE, and/or Tung-Sol datasheet specifications for new tubes of this type. The tubes must also show no shorts, show a gas current less than 0.58 mA, and a heater-to-cathode leakage of less than 10 microamps (10 uA). The tubes 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 the test results recorded on your box, too? $3 extra per tube