toroidal smoothing chokes

To supply current efficiency in response to powerful input signals while resisting power supply fluctuations, it uses DC-DC converters employing MOSFETs, toroidal choke coils and toroidal transformers.
www.techtronics.com/uk/shop/6941-panasonic-cy-m7052-car-amp...

Pure, high fidelity sound reproduction is ensured with input voltage compensation circuitry, active regulator feedback, and a pulse-width regulated (PWR) power supply with huge toroidal choke coils.
www.cardomain.com/sku/CLAAPX4012

A robust and controlled power supply is the first important step in the amplifier circuit design. A Plitron toroidal power transformer was chosen to provide ...
Finally, unlike many amplifier designs, in addition to the excellent quality solid state rectifiers used, the Masterpiece also incorporates a special toroidal choke, ...
www3.sympatico.ca/scarletaudio/masterpiece.html