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scratching my head on this one.....




I now have one channel of the 26/813/813 bread board completely noise free except for a pesky little buzz. It's not loud, just enough to be annoying. Here's the weird part; when checking some voltages I noticed that when I put a probe on the plate pin of the 26 the buzz stopped. Didn't matter if it was the pos or neg probe, it still stopped. I tried a screw driver to see what would happen, but it did not stop the buzz. I am guessing there is something in the circuit of the dvm (it was set to read vdc) that must have canceled what ever is causing the buzz, but I can not figure out what or how to apply it to get rid of the buzz once and for all. My best guess is it is a grounding issue, but I have not been able to find it yet.
I have attached the schem for the 26/845/845 as I have not yet drawn one up for the 813 version. The 813 is the very same however, except that the cathode resistors for the 813's are 470 ohms instead of 680 ohms as shown.
If anyone has any idea what might be causing this I would really appreciate it if you would let me know. It is making me crazy not being able to figure it out.



Edits: 10/20/16 10/20/16 10/20/16 10/20/16 10/20/16 10/20/16 10/20/16 10/20/16

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Topic - scratching my head on this one..... - vinnie2 11:35:23 10/20/16 (45)

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