Does AC Power Cord to Linear Power Supply matter?

Linear Power Supply is a noisy switcher that operates at 120Hz. Current from mains is drawn in narrow spikes of high amplitude. Cable should have enough frequency response to handle it and to shield it from radiating out.

In addition to high frequency noise produced by LPS there is 120Hz component very difficult to filter out. In addition LPS in amplifiers is almost always unregulated (line and load). Recently quiet switchers operating at much higher frequencies appeared. Rowland used them in Capri preamp (no other reason than noise reduction) and recent top of the line class AB amplifiers (operating at 1MHz). My Benchmark DAC1 has linear power supply inside but the newest version DAC2 has internal switcher to reduce noise by another 10dB. Modern switchers operate/switch at zero voltage/zero current while LPS switches when voltage is the highest. Rectifier diodes are most of the time too slow to react conducting for a moment in opposite direction causing voltage spikes.