One other consideration beside output Z (impedance) of the Dennon CDP is the drive level capability. If it's capable of driving the PA to full output power then I probably wouldn't use a preamp in your situation. Compare the Dennon's max. output voltage spec. to the Parasound's input sensitivity spec. to determine compatibility. Impedance-wise the Dennon's output Z should be <1/10th the Parasound's input Z to avoid possible interconnect frequency response abberations (this expanding upon Gen's post). Likewise if you do use a preamp then its' output Z should be <1/10th the Parasound's input Z, and the Dennon's output Z should also be <1/10th the preamp's input Z.
Cable-wise the philosophy of many 'philes is to maintain equal or better interconnect quality from CD to pre, & pre to P.A. I follow that approach myself, so I use the same type interconnects for both paths.
Also, regarding use of a preamp, some users have experienced better dynamic drive from an active pre than from a passive, but at the expense of some transparency. Bear that fact in mind if/when you decide to experiment with an additional stage, because an active pre may or may not enhance dynamics over your present direct-drive approach. An active pre with a detachable AC cord also permits the flexibility of experimenting with different upgrade AC cords, if you desire to try that approach regarding tonality issues. Of course if the CDP has a detachable cord, that's yet another option in that regard.
Cable-wise the philosophy of many 'philes is to maintain equal or better interconnect quality from CD to pre, & pre to P.A. I follow that approach myself, so I use the same type interconnects for both paths.
Also, regarding use of a preamp, some users have experienced better dynamic drive from an active pre than from a passive, but at the expense of some transparency. Bear that fact in mind if/when you decide to experiment with an additional stage, because an active pre may or may not enhance dynamics over your present direct-drive approach. An active pre with a detachable AC cord also permits the flexibility of experimenting with different upgrade AC cords, if you desire to try that approach regarding tonality issues. Of course if the CDP has a detachable cord, that's yet another option in that regard.