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
This post is made possible by the generous support of people like you and our sponsors:
Topic - scratching my head on this one..... - vinnie2 11:35:23 10/20/16 (45)
- RE: scratching my head on this one..... - Lew 11:56:02 10/20/16 (1)
- RE: scratching my head on this one..... - vinnie2 12:41:19 10/20/16 (0)
- Usually that is an oscillation - Chip647 11:47:52 10/20/16 (42)
- RE: Usually that is an oscillation - Cougar 19:52:07 10/20/16 (0)
- RE: Usually that is an oscillation - vinnie2 12:50:04 10/20/16 (39)
- Why aren't you using your scope for problems like this? (nt) - Triode_Kingdom 13:06:27 10/20/16 (38)
- RE: Why aren't you using your scope for problems like this? (nt) - vinnie2 13:31:17 10/20/16 (37)
- Vinnie2, make sure you have a high voltage probe... - Cougar 06:38:23 10/22/16 (1)
- RE: Vinnie2, make sure you have a high voltage probe... - vinnie2 08:34:34 10/22/16 (0)
- RE: youtube or internet search for videos ... - deathtube 667 15:14:48 10/20/16 (2)
- RE: youtube or internet search for videos ... - vinnie2 18:18:10 10/20/16 (1)
- RE: check ebay as well ... - deathtube 667 16:23:10 10/21/16 (0)
- RE: Why aren't you using your scope for problems like this? (nt) - Triode_Kingdom 14:52:21 10/20/16 (13)
- RE: Why aren't you using your scope for problems like this? (nt) - vinnie2 18:17:22 10/20/16 (12)
- RE: Why aren't you using your scope for problems like this? (nt) - Triode_Kingdom 09:27:44 10/21/16 (11)
- RE: Why aren't you using your scope for problems like this? (nt) - vinnie2 11:09:35 10/21/16 (10)
- Here you go! - Cougar 16:38:13 10/22/16 (2)
- Arrrrrrgh!!!!!! - vinnie2 04:52:48 10/23/16 (0)
- RE: Here you go! - vinnie2 18:17:19 10/22/16 (0)
- RE: Why aren't you using your scope for problems like this? (nt) - deafbykhorns 16:23:32 10/22/16 (6)
- RE: Why aren't you using your scope for problems like this? (nt) - vinnie2 18:12:10 10/22/16 (5)
- RE: Why aren't you using your scope for problems like this? (nt) - deafbykhorns 05:17:35 10/23/16 (4)
- RE: Why aren't you using your scope for problems like this? (nt) - vinnie2 09:50:01 10/23/16 (3)
- RE: Why aren't you using your scope for problems like this? (nt) - deafbykhorns 13:19:33 10/23/16 (1)
- RE: Why aren't you using your scope for problems like this? (nt) - vinnie2 14:13:41 10/23/16 (0)
- It should be an 8 ohm Power Resistor for ..... - Cougar 10:49:13 10/23/16 (0)
- RE: Why aren't you using your scope for problems like this? (nt) - elblanco 13:59:33 10/20/16 (17)
- RE: Why aren't you using your scope for problems like this? (nt) - vinnie2 14:15:04 10/21/16 (16)
- RE: Why aren't you using your scope for problems like this? (nt) - elblanco 15:57:21 10/21/16 (15)
- RE: Why aren't you using your scope for problems like this? (nt) - vinnie2 18:07:48 10/21/16 (14)
- RE: Why aren't you using your scope for problems like this? (nt) - vinnie2 08:37:44 10/22/16 (13)
- this is a cool book - elblanco 09:16:16 10/22/16 (1)
- RE: this is a cool book - vinnie2 09:46:34 10/22/16 (0)
- RE: Why aren't you using your scope for problems like this? (nt) - elblanco 09:13:22 10/22/16 (10)
- RE: Why aren't you using your scope for problems like this? (nt) - vinnie2 09:54:58 10/22/16 (9)
- What is it that you are not exactly getting? - Cougar 15:02:30 10/22/16 (8)
- RE: What is it that you are not exactly getting? - vinnie2 18:31:12 10/22/16 (7)
- RE: What is it that you are not exactly getting? - elblanco 18:44:15 10/22/16 (6)
- RE: What is it that you are not exactly getting? - vinnie2 18:53:23 10/22/16 (5)
- Make sure your using shielded internal wiring ... - Cougar 19:24:09 10/22/16 (4)
- RE: Make sure your using shielded internal wiring ... - vinnie2 03:40:11 10/23/16 (3)
- The picture you posted when I had asked... - Cougar 08:05:47 10/23/16 (2)
- RE: The picture you posted when I had asked... - vinnie2 09:56:03 10/23/16 (1)
- Glad to hear they are helping you. - Cougar 10:41:19 10/23/16 (0)
- RE: Usually that is an oscillation - vinnie2 11:53:18 10/20/16 (0)