HELP Digital bad, vinyl good???

OK, boys and girls, I need your help. Besides the obvious philosophical implications, can anyone tell me why two CDPs (Exemplar 3910 and CAL CL-10) using two diff i/cs, and two diff inputs, are highly distorted and my vinyl rig sounds great? VAC Ren Mk2 pre. Doesn't the phono stage feed into the line stage and then to the output? HELP. No XMAS tunes on vinyl.
I have not changed tubes because I always thought that the phono stage provided RIAA reverse eq; and gain to be bring the signal to line level, and then the line stage provided additional gain to the signal to provide sufficient voltage for the amp. If I am wrong (which it seems I must be), then I stand corrected. I will have to disconnect the phone and then check the line stage tubes.

Happy Christmahanukwanzadan everyone.
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Swampwalker: your description is right in how most preamps work, but as Tvad mentions, we aren't sure that's how this specific preamp works. His suggestion to disconnect the phono rig from the preamp ( interconnects, ground wire, power cord, etc... ) is where i would start. After that, it is a matter of tracking down the offending tube in the preamp, if there is one ( or two if dual mono ).

As a side note, the phono stage may not drive the line section as hard as your CD players do. As such, you might not hear as much distortion from the phono rig as you do the CD player. This would be due to the increased heardroom / lack of drive from the phono stage. This is just a guess though, so don't put too much faith in it. Sean
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It is in both channels, and it is significant. You would have to be deaf not to hear it. Seems to be mostly in the mid-range (I'm running Merlins and they are 2 ways). But my new Teres still sounds fantastic. Perhaps the line stage of the VAC uses each half of a dual triode somewhere for each channel, before the phono stage feeds in? Nope, just checked web site
Tube complement: Line stage, 2 x 8416, 2 x 12AX7; Phono stage, 3 x 12AX7.
Still wrapping gifts, will check by removing phono and then tubes, when this is done. Many thanks to all, and to all.... nahh, too corny even for me.