I assume you are talking about stereo music listening only here - if so...

The 950's output signal levels, impedance etc are all compatable with tube or solid state amplifiers - either integrated or not. In any signal path, simpler is always better, so unless you want to use the DACs in the 950, you probably would be better off running the CD player's analog output directly to your integrated tube amp's "aux" input. Although the 950 doesn't necessairly degrade the audio signal, there's really no justification for running a signal through it unless you need the DACs, bass management etc. I just prefer to not run a signal through more electronics than necessary to get the job done.

For movie playback, the 950 would of course be used as a pre/pro and you could run the left and right outputs to an unused "aux" input of your integrated tube amp. This way you would have two signal paths - one for movies, and one for stereo music only.