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Tube DIY Asylum Do It Yourself (DIY) paradise for tube and SET project builders. |
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Tube DIY Asylum Do It Yourself (DIY) paradise for tube and SET project builders. |
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In Reply to: confused again posted by vinnie2 on February 13, 2019 at 06:28:42:
You have three variables: P/K voltage, grid bias voltage and plate current. Only two of those variables can be independent. That means that you can fix two of them but the third will vary from tube to tube. No two tubes are exactly the same and no tube will stay the same as it ages. If you want to get close to a published OP I have used a simple test jig. You would need a current source that can sink the desired plate current and a variable B+ supply. The current source does not need to be anything special. A single DN2540 MOSFET, 1K carbon comp. grid stopper and 50R or 100R trim pot would do fine. Ground the grid of the tube to be tested, the current source goes between the cathode and ground along with a 1R series current sense resistor. Connect the variable PS to the plate. Use the current sense resistor to measure plate current and adjust the current source as necessary. Vary the B+ supply until the P/K voltage is where you want it. Then measure the grid bis voltage. Or set any other two variables and measure the third.
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Follow Ups
- RE: confused again - JKT 17:57:02 02/13/19 (3)
- Not Quite - Triode_Kingdom 19:24:29 02/13/19 (1)
- RE: Not Quite - JKT 19:53:45 02/13/19 (0)
- RE: confused again - vinnie2 17:58:34 02/13/19 (0)
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