Thanks St PatGuy.
It has the same look as the earlier model, CD T100 , and is already around for more than 10 years. I did my research , find out the 4 tubes 12AU7 are quite common , and there is room for upgrade. Two are working for balance & other 2 for RCA, which I don’t use.
Just wondering if I can replace only 2 tubes I use and leave the other to age ? So far , I’ve only spent not 50 hrs to burn in. A little too early to think, will look into it when time comes.