Noise in Hi-Fi has reached unbearable thresholds. How to lower static?

What do you mean?

I remember cassette tapes having terrible hiss in the day. I have been listening to a lot of music on Minidisc lately and overall like it but after somebody pointed some thing out to me I think ‘are they using white noise as a coding tool?’ (AAC Pro does) but I really have to listen to the CD next to the MD to be sure.

For amplifiers: switching amplifier with Pulse Width Modulation

and for cables: digital modulation (from QAM to OFDM) with LDPC for error correction ?