Hiss and pops and clicks and other forms of tube and record noise are not white noise.
Could this be one reason tubes (and perhaps records) sound better?
This is not a new finding, rather it keeps cropping up in the hearing literature...
"White noise improves hearing":
https://www.sciencedaily.com/releases/2019/11/191112142926.htm
"White noise improves hearing":
https://www.sciencedaily.com/releases/2019/11/191112142926.htm