There are several CD players that have volumn control and, such being the case, you might not need a pre. the larger question has to do with what you want out of your system. I used to love to use the bass and treble controls on my receiver to slightly over-do it to compensate for many things, most of which had to do with my inferior components.
Modern, well mixed CDs don't need such compensation. Some are so poorly mixed and recorded that very little, if any improvement can be obtained from knobs on a preamp.
A really high-end Cd player that has volumn control can save you some investment in a preamp. Wadia and Audio Aero are possibilities, but might not be right for you if you wish to direct your resources to your speakers and a decent
receiver/amp.
You probably need to surf some threads hereabouts and focus on priorities.