upgrading components on Bush CD790

[Simpleton]

Just bought this player.
Does anybody have info about it? I'm particularly interested in knowing if it's multibit or bitstream...

Thank you!

[Simpleton]

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/datashee...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

[guido]

The 6116 is probably a 2k 8 bit static ram, used by the decoder.
Cant imagine you have 2 different dac's, so one is probably the decoder.

As for improvements, cant help. Just wondering if the basis is good enough to spend money on

[Simpleton]

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

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?

[Simpleton]

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.

[Simpleton]

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!
What other choices do i have?
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