To Disbeliever Vaccum tubes are not just about distortion that is not correct ,for example the most sensitive medical equipment in the world and medically use Vacuum tubes uncluding your CAT scan machines why is this ?
Vacuum tubes are very stable at Voltage regulation ,
where solid state is good at currect since a cd player is very low voltage a seperate power supply is an idea filter buffer an my being totally seperate it isolates the diferent stages from any noise interaction ,and for the input stage the vacuum, tubes also help to filter the filter capacitors as well as providing a much more dimentional presentation .This is why some of the very best preamplifiers in the world are Vacuum tube .