Tube Testers: Threat or Menace?

[Winky Dink]

Reece recently gave this advice in another thread, "... still the best test for any tube is in the equipment in which it is designed to serve."

I've just spent a few days testing and retesting a few dozen used, NOS, modern, and vintage tubes with a newly-reconditioned Heathkit TT-1A and two emissions testers, and I can illustrate wisdom of Reece's statement. I have two 45's in a push-pull configuration in a 1931 radio that performs beautifully even though the tubes register nearly zero transconductance on the TT-1A. When I replace them with two spare tubes which (according to the tester) are much better, the radio's performance is, if anything, somewhat degraded, possibly because they're mismatched.

However, here are several reasons that you may want to buy a tube tester:

1. You can use it to confirm that your other tube tester is working.

2. You may be unable to test by switching tubes because you don't have access to known-good tubes or equipment that already uses the suspect tube.

3. As a learning tool, it can help the novice better appreciate how and why a tube operates.

4. It's really a fun toy to play with.

This was an eBay purchase that worked well for me. The wooden case disintegrated during shipping, but Heathkit produced a sturdy instrument, and it was well-constructed by the original owner. Putting this 15-pound beast back into operation was easy, thanks to Kent Nickerson and RDF Products who published excellent on-line guides for reconditioning the TT-1/TT-1A.



Any other thoughts on the limitations or usefulness of tube testers?