RCA etc. Matched Pair (2) 12BZ7 tNOS AT1000 TESTED Vacuum Tubes dual triode 1952-1968

This listing is for a Matched (10% in GM) Pair (2) of 12BZ7 dual triode vacuum tubes in the standard tube shape. They have a black bakelite octal base, black or grey plate, and top or bottom getter. Labels in stock include RCA, Sylvania, GE, CBS Hytron. Some of our stock is re-labeled or marked with the OEM of Raytheon, ITT, Philco. If you're looking for a particular brand, please message right as you order - we pack and ship quickly!

These tubes have been selected to match one another for optimal performance! Matching is based on plate current for power tubes, voltage drop for rectifiers, and transconductance (Gm) for other tubes.

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 2560 uMhos and 3840 uMhos, consistent with original 1952 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 0.25 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 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
Want two tubes that match one another within 10%? [Matching is based on plate current for power tubes and GM for all other tubes] $5 extra per tube.