05-23-2026, 01:12 AM
After a bit of hiatus, I'm back with just a tidbit of information. I only had the time to get R4 soldered back into place tonight and test things with tubes in, tuned to my AM transmitter, but also separately just with the antenna disconnected. I may be completely off on this but I figured, if the goal is tuned to dead air with volume down, what's deader than no antenna?
First, with the antenna disconnected, the voltages were the same as before - approx 63V on pins 4.
With the antenna reconnected, tubes in, and tuned to my AM transmitter with volume high enough to reasonably fill my small room but not loud enough to wake my wife (I hope) pins 4 tested at 91V. Across R4, coming from the voltage-dividing resistor tested at 187V, up from the typical 175V.
What are the implications of this result, would you say?
I will try to do the other tests mentioned (below) this weekend. Can we confirm if C15 is supposed to be removed or in place for the following:
Test voltage on both sides of R4 with 6A8 removed only
Test voltage on both sides of R4 with 6K7 removed only
Test voltage on both sides of R4 with both tubes out
Since I've already tested them with C15 in place, I would expect this time we should test with it removed? And to confirm, in doing so, that connection to chassis ground should be completely open for this test?
Best wishes,
Roy
First, with the antenna disconnected, the voltages were the same as before - approx 63V on pins 4.
With the antenna reconnected, tubes in, and tuned to my AM transmitter with volume high enough to reasonably fill my small room but not loud enough to wake my wife (I hope) pins 4 tested at 91V. Across R4, coming from the voltage-dividing resistor tested at 187V, up from the typical 175V.
What are the implications of this result, would you say?
I will try to do the other tests mentioned (below) this weekend. Can we confirm if C15 is supposed to be removed or in place for the following:
Test voltage on both sides of R4 with 6A8 removed only
Test voltage on both sides of R4 with 6K7 removed only
Test voltage on both sides of R4 with both tubes out
Since I've already tested them with C15 in place, I would expect this time we should test with it removed? And to confirm, in doing so, that connection to chassis ground should be completely open for this test?
Best wishes,
Roy




