|
Post by headshrinker (Marc) on Apr 16, 2022 14:41:44 GMT -7
I've got a few rectifier tubes that I have amassed over the years, most old stock but not new. Started testing some of them. I have a basic tube tester. For rectifiers there are two settings for the tester. For some of them, when I test them, one setting tests good and strong, the other dead, no emission. The question is, do both settings (halves?) of the tube have to work to be used as a rectifier? Is the rectifier really two tubes in one like a 12AX7? I know for 12AX7s if one side is good and the other is dead, that in some amps if they are only using half of the 12AX7 and it happens to be the good side of a half dead tube, things will still work fine. Is that true of rectifiers too? If so, I figure I can try the half dead ones in an amp. If things work, then it would go in the good pile, if not, it gets tossed. If amps use both sides of them and one side is dead, then I would toss them. Thanks for any help.
|
|
|
Post by GuitarZ on Apr 17, 2022 8:47:34 GMT -7
I'm not an expert, but I used my tube knowledge and Google to chime in. I can't speak to the tester settings. However, the rectifier tube isn't like the 12AX7s. Rectifier tubes don't work as halves. Below is a schematic picture that might help in understanding how they work from www.TubeCad.com. I had to scratch my head a little. Back in the day when I used to do a lot of work inside my amps (fixing or modding), they were all solid state rectifier circuits. And, I haven't had to mess with my Z's.
|
|
|
Post by RickJames on Apr 17, 2022 9:31:14 GMT -7
I love tube rectified amps! I think doc did a video on rectifiers …..
|
|
|
Post by driventone on Apr 19, 2022 7:34:59 GMT -7
Just wondering… do you just have the one tube tester?
When I first got my Hickok, I tested a bunch of 12AX7’s and set some aside that had one triode bad or very low. But, before discarding them, I decided to just double check on a simple TD-55 emissions checker. Some of them were good! I put them back on the Hickok, and that’s when I realized that the connection to the socket was pretty loose. (I didn’t realize at first because I was plugging into a socket saver - but the connection between the saver and the tube socket itself was loose).
I now have a rule that I don’t count a tube as bad u til I confirm it on two testers. Just in case.
I’m not sure this is what’s happening to you, since some of your rectifiers test good on both sides. But I wanted to mention it. Also, corroded pins can cause low or bad readings too.
|
|
|
Post by zpilot on Apr 19, 2022 7:49:16 GMT -7
I have a set of known good tubes that I use to calibrate my testers before I use them to test anything. I have their readings recorded so I can see any component drift or bad connections.
|
|