02-18-2025, 03:26 PM
Hi David,
Check the cathode bias resistor, it may have changed value. That will affect grid bias, etc. Also, verify that C26 is not bad, even though you replaced it. I had a radio give very low volume and very high distortion from a leaking coupling cap years ago. This will drive grid voltage positive and cause excess plate current in the output tube. Admittedly, this would lower B voltage due to high current. Verify that your output transformer is compatible with the tube. Although drawn as a pentode, this is a beam power tube similar to 35L6 except for the base. In fact, I have a socket adaptor from 35L6 to 35A5. The transformer should have a primary impedance of 2500 Ohm.
I have never really had an issue with excess distortion running an AA5 on 120V as opposed to the 110 or 115V nominal spec for the radio.
Check the cathode bias resistor, it may have changed value. That will affect grid bias, etc. Also, verify that C26 is not bad, even though you replaced it. I had a radio give very low volume and very high distortion from a leaking coupling cap years ago. This will drive grid voltage positive and cause excess plate current in the output tube. Admittedly, this would lower B voltage due to high current. Verify that your output transformer is compatible with the tube. Although drawn as a pentode, this is a beam power tube similar to 35L6 except for the base. In fact, I have a socket adaptor from 35L6 to 35A5. The transformer should have a primary impedance of 2500 Ohm.
I have never really had an issue with excess distortion running an AA5 on 120V as opposed to the 110 or 115V nominal spec for the radio.
"Do Justly, love Mercy and walk humbly with your God"- Micah 6:8
"Let us begin to do good"- St. Francis
Best Regards,
MrFixr55
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