upgrading components on Bush CD790

IC chips it uses

OK, i've opened it up today and found the following chips:

1x LC7881 (DAC)
1x LC7880 (DAC)
1x UM6116k (?)
2x NJM 4558S (dual op-amp, searching around reveals part nr. NJM 4558L as substitute), datasheet :

http://pdf.alldatasheet.com/datasheet-pdf/view/7234/NJRC/NJM14558L.html

1x LA9200 (analog signal processor)
1x M50930 (8-bit MCU)
And an unknown chip (covered by a dissipator), but according to the LA200 datasheet, could be an LC7860 or LC7863.

What can i do to improve the sound quality of this cd-player? Nothing too facy or i will surely mess it up...

Thanks in advance
 
Hey, i've already spent money buying it, so a few extra euros on it won't hurt...and learning is always a good deal :D

I've been searching in the meantime, and will probably replace the NJM4558 parts by Burr-Brown OPA627 opamps (too bad i can't find anything tube related :p )
Can the DACs be replaced?
 
err.... the OPA627 is out of the race, too heavy for my wallet and for the player.

I'm inclined between OPA2132/2228, AD823/712. I can only find AD826 and NJM4580 opamps here (it's a stupid country, i know), are they equivalent to the AD823? What are my other options as best replacements for the NJM4558?

Thanks once more.
 
Ok, here's what i did today, replaced the opamps for these vertical vero-boards with an 8-pin socket for changing opamps, as you can see in the picture.
It seems absurd, but no AD or OPA's can be found anywhere! :headbash:
What other choices do i have? :scratch:
I bought 2 NJM4580 for now, at least they are a bit better than the originals.
BTW, Guido, you're right, i have written donw one reference incorrectly, i have 1x LC7881 and 1x LC7860 :)
 

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