Philips CD650 mods

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Having left the tube stage running constantly I can report that for the time being Rays DOS has more detail but the sound seems more pleasing through the tube stage!!!

There are some pretty crappy components in the audio path at the mo.

I've studied the diagram and although I've got supreme's on the output, there are several MKP's in the audio path between the gain stages. I also want to replace all the supply caps with FC's.

This considered, it's got to be at a disadvantage to Rays DOS!

I'll report when I've replace the std components 😉
 
Hi Guys,

Found a NAND gate on an old project XBOX and decided to do the DEM reclock mod!

Definately worth doing! 😀

Much more contolled, tighter sound. Lower Bass extention and crisper highs. 😎

Its pretty easy to do (especially if you're already running /2 bitclock to the DAC).

I followed this diagram from ecdesigns on the ultimate NOS thread. I'm pretty sure they are running a /4 bitclock but I stayed with a /2 and it sounds pretty awesome.DEM and I2S mods Diagram

The theory starts a bit before this post for those who want to understand it, but you should get enough to impliment if you start HERE!

I'm also going to look at the I2S mods as well!

If you're not following ecdesigns thread, its worth a read! It also goes into the theory on bit decoupling on the DAC!

I'm still runnning with the valve stage and its sounding better and better. Its been playing to itself since I Friday!! I've ordered better caps for the audio path (fingers crossed for Monday)

Cheers Ian
 
The only time i've noticed the distortion is on this CD. The recording is fairly accoustic and not very busy. It seems to be the female voice thats effected. There is not a lot else in the recording other than the vocals at the time of the distortion.

Not much to go on at the moment i'm afraid. I'll try to gather some more usefull information this evening.

Ian
 
Hi Simon,

I switched the CD to my CD63 which is also pretty well tuned, and the distortion is definately not there on that player.

The distortion is pretty horrid. Its not the same every time you play the section on music. Its always similar but definately different each time you listen.


As an example,
If you completely remove your DEM cap, you will still hear music but it will distort as there will be many errors in the decoding. Its pretty similar to what I'm hearing (but on a much smaller scale).

I'm pretty convinced that it's to do with the DEM reclock.

🙁 🙁
 
That sounds very similar to what I heard with DEM reclocking. It was almost as if my DEM pins were disconnected. Not nice. I abandoned it in the end.
Glad I'm not alone in hearing that.

I would like to try it again one day, but I think there's other stuff I'd like to play with first.
 
Evening folks,

I did the swap from SAA7220P/A to SAA7220P/B today. Well worth the asking price (by several times and then some) and really easy to do on these socketed boards.

More textured and cultured sound, more detail, better sense of reverb, more 3-D etc on the CDs I've tried so far - Eleanor McEvoy, Diana Krall, Norah Jones (the vocal clipping here is even more obvious now).

Some clock tweeks next, I'm soooo behind 😀

Simon
 

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DEM update

Guy's, at the risk of opening the floodgates for abuse I feel I should report the following:-

The DEM reclock at /2 does work.

On further investigation, I found the distortion only occured above a certain volume and could not find another recording that reproduced the problem.

The problem is the cr@ppy floating (therefore hollow) shelf with little ornaments on it! The distortion I heard was Annette's little glass stars vibrating on their base! I feel like a right numpty!

Still thought I'd better come clean so you can all have a go! (at the dem mod I mean not resonating ornaments in your rooms!)

I did test again with the CD63 and it just doesn't produce the dynamics to resonate at the (un)desired frequency!

BTW Blutak on glass ornaments is apparently a no no??:devilr:

😀

I also tried a B chip over the weekend but got no sound! From the sounds of things, I need to have another go!