Lector 7T and tube rolling



I'v got this nice CD player, but would like to have even smoother highs. It has originally CVC Chelmer valves (12AT7) and I wonder if old Mullards, RCA, Siemens or other NOS would change this?
Is it important to have NOS from the 60's or is tubes from the 80's almost as good?

Thanks!
ole_s
I own this player am using some Mullards that I bought from Upscale Audio and am very pleased. The Mullards will smooth out the highs and are great in the mids.
Just some more info:

I've now tried with Siemens NOS as well as RFT NOS (former eastern Germany I quess).
The RFT tubes are best in my system, giving more precise bass as well as natural imaging. Detailed without beeing edgy.

Mullards are next on the list :-)

Ole
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