I have been browsing the information about high frequency noise influence on the sound quality for quite a while. Power regenerators and power conditioners are made to prevent the free passage of HF noise to power supplies. I know that HF noise suppression is not the only goal of power regenerators, they do much more than that, but this topic is just about HF noise.
I found out that audio devices are affected by two kinds of HF noise - common mode and differential mode mains noise. Common mode mains noise is created by external factors - radio (RFI) and all the wireless communications (TV, cell phones, etc.). Differential mode mains noise is created by local factors - power supplies (linear and switch mode) and digital circuitries.
The range of HF noise extends from 10kHz to 500MHz. But what exact range can possibly affect the sound quality of audio components?
In the specification of all the latest PS Audio Power Plants there is the following characteristic:
“Noise Reduction: 100kHz – 2MHz >80dB”
I would like to know, is this range of noise (100kHz - 2MHz) the most critical for audio devices? What about higher frequencies (2MHz - 500MHz)? Is this higher frequency range not important for audiophile purposes and thus can be ignored?
Thanks in advance for all well structured answers.