This Western Electric 420A is a genuine NOS (new old stock) tube, and features select yellow paint on the tip and on the box. Minimum transconductance (Gm) on the Amplitrex tester is 1.0 and NOS tubes typically test around 1.5. This tube tests at 1.5 with plate current at 1.9mA.
TESTING: The tube(s) in this sale have been tested on an Amplitrex AT-1000 tube tester (fixed-bias mode), which is a laboratory-grade tester capable of supplying the user with precision measurements. It tests for heater-cathode leakage, gas, mutual conductance, and plate current. Please note that no tube testers are identical and my test results will likely differ slightly from yours.
RETURNS: I will gladly take your tube(s) back for a full refund if you're unhappy for any reason. Yes, it's that simple! Please note that I reserve the right to issue partial refunds if tubes are missing, damaged, or without original boxes (when applicable).
INTERNATIONAL BUYERS: Please read and understand the following before making a purchase:- First Class Mail can take more than 60 days for delivery, so please be patient. If you need your tubes faster, select USPS Priority Mail or USPS Express Mail.
- I will not declare a lower value for any reason.
OTHER TUBES FOR SALE: I have many premium tubes for sale and will combine shipping if you buy multiple items. Click the links below to see what else is available!- Audio Preamp Tubes (12AX7, 12AY7, 6SN7, 6DJ8, etc)
- Audio Power Tubes (6V6, 6L6, 6550, EL34, etc)
- Audio Rectifier Tubes (5Y3, 5U4, GZ34, etc)
- Radio Transmitting Tubes (6146, 811A, 3-500Z, etc)
- Other Tubes and Accessories (eye tubes, Nixie tubes, CRTs, sockets, etc)