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-   -   Sony CDP270 or LC7881 DAC schematic (http://www.diyaudio.com/forums/digital-source/8144-sony-cdp270-lc7881-dac-schematic.html)

baforestal 30th November 2002 03:40 AM

Sony CDP270 or LC7881 DAC schematic
 
I''m looking for the DAC and ouput amp schematic for a Sony CDP270. It looks like it uses a LC7881 DAC but I have not found a pin-out for this chip.

Thanks, Bruce

jean-paul 30th November 2002 07:41 AM

Hello Bruce,

The LC part is a Sanyo DAC. I have the datasheet somewhere.
The Musical Fidelity X-DAC has the same one. When I find it I will attach it.

Jean-Paul

jean-paul 30th November 2002 06:36 PM

Sorry Bruce,

I tried to find it in my collection of pdf's. It's not there anymore or it has another name than the chip.
I remember rather poor results from this DAC in comparison to BB products in terms of performance / sound.

Sorry,

Jean-Paul

baforestal 30th November 2002 09:50 PM

Jean-Paul,

Thanks for looking. I have found numerous links to the LC7881 but not any chip pinouts. At this point I think it's better to put in a better DAC. Of course I'm not sure if this Sony CDP-270 player is worth the upgrade. I have lots of experiance in design and prototype/test but I've never done a DAC upgrade. Seems like a fun project. Do you think this CD player is worth upgrading or should I look for better quality player?

Thanks, Bruce

jean-paul 30th November 2002 11:02 PM

I don't know this specific player Bruce. I googled and found out it's a 200 disk changer !
I wouldn't bet my money on the mechanical quality of the mechanism. Till now most changers I've seen were rather poor designed mechanically.
If it functions OK you can upgrade the DAC if you like. If well designed the results of the new DAC will be a lot better than the original LC7881. You can see it as a project you can learn a lot from.
With the experience you get from the surgery the next maybe more exclusive/expensive cdplayer will be easier to do. And it really is fun to do !

baforestal 1st December 2002 07:51 PM

Sony CDP270 DAC upgrade project
 
Jean-Paul,

The CDP270 I have is clearly a single disk player, although I've seen several links that label it as a 200 disk changer. http://www.allsearch.de/soundcheckhi...s/cdp270_1.jpg

I think replacing DAC is a good way to get experiance before I tackle a top-end upgrade. In it's original design it has 4 times oversampling digital filiter and digital de-emphasis. My next step is chosing a new DAC and peripheral chips. I opened the player and took a look at the PCB. There is a unused square cut-out in the back panel next to the left and right RCAs. There is no connector soldered in the three PCB pads below the cut-out. The signal trace goes from the pads to the CXD1125 DSP chip. Could this be a digital output that's just unused on this model?

I will do some reading of the many excellent posts on this forum regarding upgrade possibilities. Any suggestions on what chips to use? If the unused connector is a digital output would it be better to build and external DAC?

Thanks, Bruce

jean-paul 1st December 2002 09:06 PM

Quote:

Could this be a digital output that's just unused on this model?
Hello Bruce, you are probably right. I advise you to buy the service documentation for your model from Sony. I think they are around 10 US $. Then you now what you're doing in the player ;)

An external DAC suffers a lot more from jitter than an internal one.
I would build it in the player, that way you don't have to go SPDIF.

Concerning chips: the BB ( now TI ) PCM1704 and the DF1704 filter are popular around here. Drawback is their SSOP case ( SMD ). Other good but hard to get ones are PCM63 and the filter DF1700 ( old but good ) Since I am contaminated with the non OS virus I am not the best person to advise you on this matter....

preatorius 26th December 2002 01:03 PM

Re: Sony CDP270 or LC7881 DAC schematic
 
2 Attachment(s)
LC7881

Regards

east electronics 15th November 2012 06:18 PM

seen that this is a very old thread ...excuse my question since i have no idea when it comes to digital ...Question is

Is there any of these chips that will be a drop in replacement for the LC7881 and will upgrade the digital section ?

All the suggestions above require other mods also ?

Thanks for the help
Kind regards
Sakis

stephensank 16th November 2012 01:02 AM

There is no drop-in replacement for the LC7881 that I have run into, but I can tell you that the LC7881 can be a very, very nice sounding dac chip when given clean, abundant power supply & a minimum of output stage circuitry.


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