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Re: Tube Tester results - valid for guitar amps?

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From your comments it looks like the tube tester is checking the gm of the tube. But what you say about the EH tube is opposite of what the New Sensor web site says - "high gain and ultra low noise". Therefore the tube should have a high merit score if the gain is high, since gm (transconductance) is a measure of gain of the device. If my particular tube has low gain/low gm, that may explain the poor test result, but it also does not comply with the New Sensor spec. JimL commented that the tube tester is looking at electron emission, this i imagine would be analogous to measuring current from the device at a particular bias point. So it still is not clear what is going on - are the EH tubes crap, or is the tube tester useless ?
It makes sense of course to test the tube in the circuit that it is being used in, but this is not practical and it is a pain in the neck. For one, it's a pain to get the schematic and layout of some amp designs, and schematics do not always have the voltages and currents indicated. Secondly, it's a double pain to take apart the amp to get access to the circuit, every time i want to test a tube. This is a ridiculous science project that i don't have time for. A tube tester machine should be a valid and painless way to check the quality of a tube. Wishful thinking...


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  • Re: Tube Tester results - valid for guitar amps? - Hiwatt-tone 15:28:36 08/19/05 (0)


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