Zenith 3DJ3 Tube. Tested and spec'd with Hickok TV-2 / 6000

Description: Below are test results from a calibrated Hickok TV-2 or Hickok 6000 (label in photos indicates which test set was used): 46 / 25 min. to pass Interpreting test readings (from a practical sense)1. Emissions - the amount of electrons a tube can produce. Think of this as the water pressure going into your house. You will need a minimum amount of pressure to water your lawn and plants. There is no unit for measuring emissions so it's typically listed as an arbitrary number referenced to a minimum acceptable value. As long as the tube is above the minimum value, it is producing sufficient emissions for full performance given other factors pass. 2. Transconductance (Gm) - the proportion of signal voltage into the tube vs. output current. It is essentially how sensitive a tube is in amplifying a voltage signal into a current signal. Using the water valve analogy, transconductance is how well you respond to controlling the water valve when your spouse yells at you to "turn up the water!" while watering plants. If you have high Gm, you will respond to that command by opening the valve a lot vs. a small, incremental amount. Note that diode tubes are only tested for emissions - they do not have a "control valve" for measuring Gm and are considered "wide open" all the time. Emissions readings are easier to measure and though I pay attention, I tend to pay closer attention to the transconductance readings of a tube since it dictates the ability for that tube to respond to signal changes. Back to our analogy, the house water pressure would be fine anywhere from 50 PSI to 70 PSI and no one in the house would notice a difference; but, it is much more important for you to accurately control the water valve according to your spouse's instructions when watering the plants! Finally, keep in mind that these test results present a good objective but partial understanding of a tube's state. Different tube testers use varying arbitrary values and factors like the internal mechanical integrity of a tube are largely unmeasurable. Having said that, I've found vacuum tubes to be pretty hardy having survived drops and even tubes that test below minimums are still able to perform. Background on the test units I use:The TV-2C/U was designed by Hickok for the Military and produced by military contract manufacturers to military standards. Because of this, it is overbuilt and each component used is of high quality and ruggedness. It can measure shorts, undesirable gases in the tube, Emissions, and dynamic Transconductance with very precise control of signals being applied to the tube (dynamic transconductance meaning it uses waveform signals to mimic closer-to-operating conditions vs. a fixed static signal). My TV-2 was calibrated and verified with a calibration tube measured by a laboratory tester. (Calibration date 9/25/21). The test results of the TV-2 is quantified as a percentage of a new tube's Gm based on datasheet specifications. This percentage is much easier to understand vs deciphering raw Gm numbers and checking tube datasheets to calculate where a new tube is expected to be. A minimum value is also listed; below which a tube's performance is assumed to be unsatisfactory. The Hickok 6000 is a prosumer tester capable of measuring emissions and dynamic transconductance, shorts, and undesirable gases as well. Calibration on 9/20/21; also verified with a calibration tube measured by a laboratory tester. The test result of the Hickok 6000 is in umhos - the unit of Gm (transconductance) - you would have to look up the datasheet of a tube to see what the Gm of a brand new tube calls for to see how close (or above) a tube is from "new" specifications. Diode tubes or multi-element tubes that contain diodes will have diode emissions test results listed. This is an arbitrary value so it will be listed as tested value vs. minimum acceptable value. If you have any questions please let me know. I am an electronics and firmware engineer by trade. Working on vintage electronics / tube radios is a hobby and passion of mine. I strive to make my customers happy and guarantee quality and functionality in the tubes I sell. Feel free to ask any questions you have about this tube. Thanks and have a nice day!Jason

Price: 4.95 USD

Location: Benicia, California

End Time: 2025-01-16T19:44:36.000Z

Shipping Cost: 3.95 USD