Upgrading op amps in a Denon DCM-460 CD player
 

I have a Denon DCM-460 CD player which I bought new in '94. I'm pretty happy with it mechanically. It's never given me any trouble but it sort of the weak link in my system. I have an AVAHIFI tube preamp, and an AVAHIFI hybrid power amp I opened it up today to check what kind of OP AMPs it was built with. I found 5 JRC4558. I'd like to remove these and solder in DIP-8 sockets, so I could try some other op amps. I've been looking thru this website, and some other websites for a while. The OP AMPs I'd like to try are the OPA627. I also saw some favorable reviews of the AD825 (not 826).
I also found 2 BA15218 OP AMPs. Should I replace these ?

I don't know what it has for a DAC ( or DACs). What are some common DAC numbers? Are the DACs as swapable as the preamp OP AMPs ?

Any recommendations? The music I listen to the most is Classical, and some Jazz.