Power Supply with tube rectification ,any good ?

Hi, Would anybody please explain what is tube rectification ? Some Tube Preamp manufacturer produced
2 kind of Power Supply for use with the designated tube preamp - one is the standard SS power supply;the other is tube rectified power supply. Would there be any sonic advantages of the latter over the former ?
Your explaination and suggestions is highly appreciated and thanks in advance
A rectifier changes the AC volts into DC volts. I could relate only to guitar amplifers as to when the power supply sags ("Brown Sound").
I've yet to hear SS rectification sound as good as tubed rectification. I'm sure there are exceptions, but the SS rectification needs to be fast and quiet which is not always the case.