Thanks for the info, The amp does not have any tubes in it and I have
none. Would like to find at lest one to start the testing.
Thanks again de John KØCQW
STEVEN & NANCY FRAASCH wrote:
>Don't go too crazy replacing tubes. More often that not, a tube is still
>quite good after years of use. Assuming that the filaments are wired in
>parallel, plug one tube into the amp at a time, key the amp and monitor
>quiescent plate current. The resting current should be within 20% of the
>group mean. If you have an assortment of tubes, I would match them for
>resting current (again, checking them one at a time assuming filaments are
>parallel connected). If you have an extreme outlier that has low resting
>current, I would suspect that it is weak. Use tubes with similar gain
>together. The RF transistor industry used to do this by marking BJTs with an
>ink to indicate Beta grouping.
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