Advice on aging Krell CD player

In the early 90's I purchased a Krell CD-DSP player along
with a Krell KSA 150 amp and a KBL preamp. Here it is 2006
and this system is still going strong and a joy to listen to.Mostly classical, lots of solo piano, and vocal performance.
Enter the Krell CD-DSP, smooth on top,great bass,decent soundstage and a completely black backgroung. Well not any
more,seems like on most recordings there is a noise, kind
of a sputtering sound at the start of the track and is very prominent on small vocal recordings the whole way thru.
Should I just replace the unit or consider having it upgraded.And if so, who might you recommend to do such work.
I suspect the DAC's have had it and probably the noise I describe is jitter.Really hate to part with her.
I appreciate your time and look forward to your reply.