good/best CD player with variable out

I agree with Mejames.

I own the Audio Aero Capitol Mark 2. I replaced my preamp, dac, and transport with this unit. I also saved the noise and distortion created by aditional power cords and interconnects, not to mention their cost.

Good Listening,

I third the Audio Aero recommendation, the most musical player I have ever heard.

I have to confess that I have never personally tried the Audio Aero Capitol, I have only auditioned it at the shows. I did try the Wadia 861 and my own Accuphase 75V connected directly to my amplifier, and they did not sound even close to what you get through a good preamplifier !
I think that all our recommendations might help, but at the end if you have the possibility to perform a test, that is what you should do.

Audio Aero Capitole MKII is highly recommended !

AA has high quality analog volume control and high output impedance that would be perfect match with your tube amp or any medium input impedance SS amp.

You like having a good tube preamp,DAC,CD transport,2 interconnects,and 2 power cords which would cost you more than $20,000 to get the same performance.(I'm not kidding)

Simple the best !

Depends what your budget is.
If you have a big budget, I would not suggest running a digital source with variable volume into an amp.
A great active preamp make a system sing.
If you are on a budget, well going digital direct into an amp, is an option.

KF