RE: Tube Tester Variation Question Again . . .

Posted by Alpha Al (P) on April 23, 2010 at 10:16:58

In Reply to: Tube Tester Variation Question Again . . . posted by hiatt@alaska.net on April 22, 2010 at 23:05:54:

Hi Mu tubes like 7591 have a tendency to oscillate in a Hickok tester. If that is happening, the reading will be abnormally high.

If grounding one hand to the tester and shielding the tube with your other hand changes the reading, it is oscillating.

Hickok apparently knew about this problem, because later versions have ferrite beads on the leads to each socket pin. A very small capacitor (100-250pF)from plate pin to grid pin will stop it as well.

Al

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Follow Ups Full Thread

Topic - Tube Tester Variation Question Again . . . - hiatt@alaska.net 23:05:54 04/22/10 (13)

RE: Tube Tester Variation Question Again . . . - JSTRM 01:42:20 04/24/10 (1)

Okay, it took me awhile to catch on to your "manu" lingo . . . nt - hiatt@alaska.net 21:21:07 04/24/10 (0)

RE: Tube Tester Variation Question Again . . . - Alpha Al 10:16:58 04/23/10 (1)

Thanks for the suggestion. The oscillation was also mentioned by - hiatt@alaska.net 23:55:50 04/23/10 (0)

RE: Tube Tester Variation Question Again . . . - Tom Bavis 06:03:44 04/23/10 (1)

I have the following combination of NOS and used tubes and their results . .. - hiatt@alaska.net 08:27:04 04/23/10 (0)

RE: Tube Tester Variation Question Again . . . - FenderLover 02:05:49 04/23/10 (6)

I don't know if the seller used a calibration tube, and my use of - hiatt@alaska.net 22:21:28 04/23/10 (0)

RE: Tube Tester Variation Question Again . . . - Ron Oehlert 15:29:42 04/23/10 (4)

RE: Tube Tester Variation Question Again . . . - JSTRM 10:05:02 04/24/10 (3)

Don't worry, I listen to music every day and buy tubes about - hiatt@alaska.net 21:18:33 04/24/10 (2)

RE: Don't worry, I listen to music every day and buy tubes about - JSTRM 21:55:15 04/24/10 (1)

Would you buy an auction tube without asking for or reading the - hiatt@alaska.net 00:02:15 04/25/10 (0)

Follow Ups

RE: Tube Tester Variation Question Again . . . - Alpha Al 10:16:58 04/23/10 (1)

Thanks for the suggestion. The oscillation was also mentioned by - hiatt@alaska.net 23:55:50 04/23/10 (0)

RE: Tube Tester Variation Question Again . . .

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