08-27-2026, 02:12 PM
Couple of ideas:
Run the radio without the 6F6. There should be no noise. If you hear crackling, the bypass cap between the 6F6 plate and cathode is bad.
If you have a 6V6 or 6K6 you can temporarily try them in place of the F6. Bias will be wrong, but the radio will play.
If you still have the noise, unplug the other tubes but leave the output tube in place. If you still have crackling, then there is an issue with the output tube circuit (Tube, transformer, speaker voice coil and leads, cathode resistor (part of the power supply in your radio) or in the power supply (rectifier, filter cap, field coil, power transformer, etc.).
If the crackling goes away, then the issue is elsewhere in the radio.
Check for cold solder joints or a bad cap that you haven't changed.
Run the radio without the 6F6. There should be no noise. If you hear crackling, the bypass cap between the 6F6 plate and cathode is bad.
If you have a 6V6 or 6K6 you can temporarily try them in place of the F6. Bias will be wrong, but the radio will play.
If you still have the noise, unplug the other tubes but leave the output tube in place. If you still have crackling, then there is an issue with the output tube circuit (Tube, transformer, speaker voice coil and leads, cathode resistor (part of the power supply in your radio) or in the power supply (rectifier, filter cap, field coil, power transformer, etc.).
If the crackling goes away, then the issue is elsewhere in the radio.
Check for cold solder joints or a bad cap that you haven't changed.
"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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