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That's not unusual with conventional 60Hz transformers. It doesn't indicate a defect, just a low quality transformer.mine definitely has an audible hum and the chassis seems to vibrate
That's not unusual with conventional 60Hz transformers. It doesn't indicate a defect, just a low quality transformer.mine definitely has an audible hum and the chassis seems to vibrate
That makes no sense since the radio antenna is designed to pick up all radio frequency signals including EMI. You may be confusing EMI shielding with EMI suppression or noise suppression, a feature of some AM radios. Noise suppression is a euphemism for audio clipping or audio limiting that removes the loud peaks in AM audio that are caused by EMI.Older car radios may not have enough emi shielding from higher voltage hydro sources. My car radio is not old but also not top of the line and i hear loud buzzing when ever I drive under High Voltage Hydro wires.
I may not know the correct terminology but car radios are designed for cars and the volts in your house and the 120 volt power supply do not exist in a car environment so car radios do not necessarily have to be designed and built to block out those signals that are not normally present. So it could be a combination of things from noisy hydro lines, bad voltage switching in the transformer and the radio picking up noise that exists in a house environment but not in a car. Not to mention am antennas are built into the radio not external like fm that also does not help.That makes no sense since the radio antenna is designed to pick up all radio frequency signals including EMI. You may be confusing EMI shielding with EMI suppression or noise suppression, a feature of some AM radios. Noise suppression is a euphemism for audio clipping or audio limiting that removes the loud peaks in AM audio that are caused by EMI.