10-13-2014, 03:37 PM
Hum-bucker is in the speaker, not in the chassis.
It is a turn (few turns) of a wire around the field coil, connected in series with voice coil, but so the winding goes opposite to it; this way the influence of the field coil to the voice coil is countered.
However your slight hum might be due to:
1. Not enough filtering.
2. House wiring (I have that). Good way of checking - have a transistor battery radio on the same frequency and see if it also hums. Short of taking care of your house's wiring there is not much that can be done.
3. Hum-bucker wired in backwards.
4. Transformer buzzing.
5. Power line close by. Also not much can be done.
It is a turn (few turns) of a wire around the field coil, connected in series with voice coil, but so the winding goes opposite to it; this way the influence of the field coil to the voice coil is countered.
However your slight hum might be due to:
1. Not enough filtering.
2. House wiring (I have that). Good way of checking - have a transistor battery radio on the same frequency and see if it also hums. Short of taking care of your house's wiring there is not much that can be done.
3. Hum-bucker wired in backwards.
4. Transformer buzzing.
5. Power line close by. Also not much can be done.
![[-]](https://philcoradio.com/phorum/images/bootbb/collapse.png "[-]")
