Certainly any time a powered passive or active component vibrates in an electric and magnetic field, parasitic voltages and currents will arise. Electromagnetic fields are everywhere. In fact, all matter including biological matter, is nothing more than an electromagnetic field condensate living in an electromagnetic field. What that electromagnetic field really is no one knows but it appears to be a practical abstraction that we make use of.
A manufacturer like Onkyo, surviving with razor thin margins, would never add parts to a design that are unnecessary. Rather, they optimize the design and that's a much tougher engineering feat than manufacturers who use 50 pounds of steel for their chassis.
For patent purposes, they only say as much as they need to and no more:
"When the AV amplifier is powered ON, the power transformer 90 and the exhaust fan 91 start vibrating, and the vibrations are transmitted to the lower chassis 82. Then, the vibrations are transmitted also to the signal processing board 88 and the amplifier circuit board 89, which are fixed on the upper surface of the lower chassis 82. Vibrations of the power transformer 90, etc., influence the audio signal being processed by the signal processing board 88 and the amplifier circuit board 89. Specifically, the audio signal is contaminated with vibration-induced noise, which affects the quality of the sound output from the speakers."
I think, but can't be sure, that any parasitic noise detracts from the perceived soundstage and imaging and also leads to listening fatigue. Transformer hum is certainly very noticeable but there is other, less noticeable noise that likely gets to us and we don't even know it.
Last edited by Mojo; 04/08/21 04:42 AM.
