Home › Forums › Help/Technical Questions › 12AT7EH Tube Glow

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  • December 6, 2009 at 2:21 pm #79473
    GearOholic
    Member

    Hi, this may have been covered before but if so I cannot find it. Do electro-harmonix 12AT7EH tubes glow? I have them next to a JJ 12AX7 and it glows like crazy but the AT7 does not. I have put three Electro Harmoncix AT7’s in this position but none glow. Could all 3 be bad tubes??? Thanks.

    December 7, 2009 at 11:07 pm #104962
    voretaq7
    Member

    If these are designed the same way as the 12AX7EH the filament is almost completely surrounded by the other elements so there isn’t much glow. If you get really close you can see the top of the filament sticking out a bit & it will be glowing a dull red.

    Best test without a tube tester: Run a signal through the device and see if you get output :-)

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