[sdiy] A simple 12AX7 vacuum tube tester schematic..

[Scott Gravenhorst]

jpdesroc at oricom.ca wrote:
>My tube tester is a B&K Dyna-Jet 707 
>Like this one:
>http://cgi.ebay.com/Vintage-Working-B-K-Dyna-Jet-707-Tube-Tester-55899
>9_W0QQitemZ140198084338QQihZ004QQcategoryZ132QQssPageNameZWDVWQQrdZ1QQ
>cmdZViewItem
>
>and is in very good condition.
>The problem with this tester is that
>for the 12AX7 the manual says:
>GOOD if it reads 22 or more on
>a 120 scale!! Most tested 12AX7's go
>from 15--23..! Not quite acurate.
>I don't want to mess around with the internal
>circuitry to get a better reading.
>So I'd like to get opinions about my
>idea of building a standard stage to test
>the 12AX7 gain as detailed in my previous post.

I see, you're right, that doesn't tell you much.  Yes, I'd make a specific tester.
 Another member (R.Schmitz?) laid out what I would do.  I'll bet it comes in handy
quite often for you.

>
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-- ScottG

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-- Scott Gravenhorst
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