09-22-2025, 06:57 AM
Anyone who has recommendations on how to determine the polarity relationship between the voice coil, the bucking coil, and the field coil in a field coil speaker?
I rewound the field coil due to corrosion and was unable to determine the direction wound, when completed I connected the voice coil red to the bucking coil tan, which left the voice coil tan and bucking coil red, which were connected to their original output transformer terminals. Everything seems fine and there is zero hum at the speaker with the volume control at minimum, which would indicate to me the correct polarity relationship as the field coil ripple and audio stage hum are constant regardless of the volume control position.
I did notice that there is some hum present at high volume settings such as when tuning in a really weak station at night. Only noticeable above about half rotation…
Normal, or should I try flipping polarity of one of the coils? Seems it wouldn’t matter which one….am I overthinking or missing something?
I rewound the field coil due to corrosion and was unable to determine the direction wound, when completed I connected the voice coil red to the bucking coil tan, which left the voice coil tan and bucking coil red, which were connected to their original output transformer terminals. Everything seems fine and there is zero hum at the speaker with the volume control at minimum, which would indicate to me the correct polarity relationship as the field coil ripple and audio stage hum are constant regardless of the volume control position.
I did notice that there is some hum present at high volume settings such as when tuning in a really weak station at night. Only noticeable above about half rotation…
Normal, or should I try flipping polarity of one of the coils? Seems it wouldn’t matter which one….am I overthinking or missing something?
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