Upgrading CD player DAC (AD1855)

[Puggie]

I have a Nakamichi MB-100 car CD player here, it has a digital out and separate DAC unit I'm looking to improve/modify if possible. The unit takes 2 SPDIf signals uses a 74HC153 to select and route to the Digital receiver chip a Yamaha YM3436D. This then outputs to an Analogue Devices AD1855 DAC with uPC4570 op-amps doing the final I/V conversion before the signal disappears into an analogue EQ section.

So my question is there a relatively simple way to improve on this setup. Would the AD1852 give a significant improvement, I know the receiver will limit me to 24bit 48k signals being passed to the DAC but the S/N ratio and general quality of the 1852 would be better if they are a direct replacement. I assume de-coupling caps sprinkled liberally on supply rails to everything would only improve matters and could the 4570 be improved upon?

Thanks for any advice, would schematics and pics of the board help at all with peoples advice? Its a fairly archaic piece of kit but it suits my purpose very well.

[adhiyasa38]

Using existing dac only as enclosure, install new dac pcb, like ak4393, I'm succesfull to implant ak4393 dac to Nakamichi TA25.

[adhiyasa38]

Not interested, just some photo

[Puggie]

Thanks for the piccies, at the moment though I just want to see how far I can take the existing Nak board.

I've dropped the AD1852 in and it works, I'm yet to measure the response and see if noise figures etc have improved.