CD850 Mk II mods
Hi,
I have bought a '850 Mk II in 1992 or so, and modified it. On the separate SAA7350 board I replaced the decoupling Elco's with small form factor Tantalum Elco's, I think 47 uF or 22 uF or so, 16 Volts, in any case no Big ones, since I wanted high frequency decoupling for this high frequency chip. The sound after that was very appealing compared to the previous setup, with mor firm bass lines (not more dB's, but more easily recognised bass guitar lines).
The SAA7322 is acting as 4 times oversampling filter. This chip is actually identical to an SAA7323, but with a lower accuracy, so after manufacture Philips labelled these 7322. Pretty useful as OS filter since they are still bit correct.
The SAA7350 does a 32 times interpolation on top of the 4 times OS signal, and then performs a 2 times "sample and hold", yielding a total of 256 oversampling for the Bitstream DAC in the '7350.
In fact, I passed my player on to a friend of mine, who is having a lot of fun from it. Data sheets available for the SAA chips if you need them, and a friend of mine MAY have a technical manual for this player (not a user manual)....
Good luck, AudioGuy.
Hi,
I have bought a '850 Mk II in 1992 or so, and modified it. On the separate SAA7350 board I replaced the decoupling Elco's with small form factor Tantalum Elco's, I think 47 uF or 22 uF or so, 16 Volts, in any case no Big ones, since I wanted high frequency decoupling for this high frequency chip. The sound after that was very appealing compared to the previous setup, with mor firm bass lines (not more dB's, but more easily recognised bass guitar lines).
The SAA7322 is acting as 4 times oversampling filter. This chip is actually identical to an SAA7323, but with a lower accuracy, so after manufacture Philips labelled these 7322. Pretty useful as OS filter since they are still bit correct.
The SAA7350 does a 32 times interpolation on top of the 4 times OS signal, and then performs a 2 times "sample and hold", yielding a total of 256 oversampling for the Bitstream DAC in the '7350.
In fact, I passed my player on to a friend of mine, who is having a lot of fun from it. Data sheets available for the SAA chips if you need them, and a friend of mine MAY have a technical manual for this player (not a user manual)....
Good luck, AudioGuy.
Re: Some small changes.
Of course.
Did you bypass the PSU properly under the OPAs (under the circuit)?
Your pic shows a poor PSU bypass, as usual in most commercial products.
You haven't heard yet what the OPA2134 is capable of doing.
With that bypassing even a poor NE5532 may sound better to you.
ashok said:
Of course.
Did you bypass the PSU properly under the OPAs (under the circuit)?
Your pic shows a poor PSU bypass, as usual in most commercial products.
You haven't heard yet what the OPA2134 is capable of doing.
With that bypassing even a poor NE5532 may sound better to you.
After having a look at some schematics of the Philips CD850, I can confirm that it's not the same player as my Marantz CD62.
There are some common things, but not everything.
The philips has 2 (symmetrical) SAA7321 DACs, using the built in filter I think. And a SAA7220 used only for the spdif out.
The Marantz has a 7350 DAC, using the 7322 as a filter.
There are some common things, but not everything.
The philips has 2 (symmetrical) SAA7321 DACs, using the built in filter I think. And a SAA7220 used only for the spdif out.
The Marantz has a 7350 DAC, using the 7322 as a filter.
schematics
I have some schematics from RR. Where there is a 7321 in the schematics, i have a 7322 on board. But for the rest it looks the same.
I also put a request to audioguy (actually his friend) for the manual...,as you did, but seeing the added 'MAY' I guess that it's not available (anymore).
But I think the schematics from RR are usefull unless sombody says the differences are too big.
BTW I received the parts for the DDDAC1543 (thanks Doede !). So it's time to roll up my sleeves and build me a 'tower'......
I have some schematics from RR. Where there is a 7321 in the schematics, i have a 7322 on board. But for the rest it looks the same.
I also put a request to audioguy (actually his friend) for the manual...,as you did, but seeing the added 'MAY' I guess that it's not available (anymore).
But I think the schematics from RR are usefull unless sombody says the differences are too big.
BTW I received the parts for the DDDAC1543 (thanks Doede !). So it's time to roll up my sleeves and build me a 'tower'......
Re: schematics
what schematics did you get from rr?
Peng said:I have some schematics from RR. Where there is a 7321 in the schematics, i have a 7322 on board. But for the rest it looks the same.
I also put a request to audioguy (actually his friend) for the manual...,as you did, but seeing the added 'MAY' I guess that it's not available (anymore).
But I think the schematics from RR are usefull unless sombody says the differences are too big.
BTW I received the parts for the DDDAC1543 (thanks Doede !). So it's time to roll up my sleeves and build me a 'tower'......
what schematics did you get from rr?
Philips CD850 service manual
Hello Bricolo, Peng,
I now have obtained this Philips CD850 (non Mk II) service manual, it's a 2,8 MB PDF file. Please send me an email so I can have your addresses and mail them to you. I will post this one and some 80 others sometime in the near future on my website...
Regards, AudioGuy
Hello Bricolo, Peng,
I now have obtained this Philips CD850 (non Mk II) service manual, it's a 2,8 MB PDF file. Please send me an email so I can have your addresses and mail them to you. I will post this one and some 80 others sometime in the near future on my website...
Regards, AudioGuy
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.