Philips CD373 what mods?

[Leonar]

Hi

I was testing a 1400 Euro Quad cdp last friday
I liked the sound

I have a philips cd373 which i like to improve

The sales person told me that old philips could be close as good if modded bij shortcuting the see.... processor chip and replacing the end Transistors and using a ring travo with improved Condensators.

I really like to try this.

Could someone please give me some directions?
And if possible a schma of the 373?

thanking you in advance

Leonardo

[poynton]

Originally posted by Leonar
Hi


I have a philips cd373 which i like to improve



Leonardo

Can you post a photo of the insides? I cannot find any reference except that it has cdm4

Thanks
Andy

[Leonar]

The dac is a TDA1541

and it has volume control via the remate

Thanking you in advance

Leonardo

[poynton]

Hi.

I have seen this board and variants in several Philips and Marantz players. eg Philips cd610, cd472 and Marantz cd65mkII.
A similar layout was also fitted in some Mission cd players.

The output is fairly conventional so the upgrade route follows the usual pattern.

1. remove the output muting transistors

2. Replace the standard opamps with 'better' ones eg AD826

3. Improve the power supply by replacing the diodes with faster, low noise versions and replace the standard caps with Black Gates.
4. Do not use the built in volume control - keep it at maximum
5. Remove the headphone driver amp and associated circuits.

If I find the circuit, I will post later.

Andy

[poynton]

Hi.

Under the small daughter board, at the rear of the player, does it look like there are 2 extra holes in the back panel (blanked off) next to the RC5 sockets?

It looks from the pictures that there is not a direct output and that all the signal is routed via the volume control.

For optimum sound, it would be better to fit 2 high quality sockets on the back panel and bypass the vol. control.

How are your electronic / soldering skills?

Andy

[Leonar]

Many thanks Andy!

That is a lot of information and somewhat criptical for me now.

My soldering experiences are somewhat modest.

During my study I made several eched boards (using the "Edding methode")
One of the projects concerned an 8bit AD conf with 8 chanel multiplexer making a digiital scope together with my very simple home computer running a machine lang prog (Z80) selecting port - reading in value - storing in memory (DMA) - which after some seconds of measurements been put on the screen with high level lang. I also wrote a word processor and some sort of graphical program for this computer to make my reports...(good old times)
Those were simple boards compared to this.

Your questions regarding the black holes. Please find some more pictures.
I hope they give you more insigt in this matter.

If you have any more suggestions - informatiion etc. would be great.

Thanking you in advance,
Leonardo

[Leonar]

And what about Non OS?

Connect port 1,2,3 of 7210 with 1,2,3 of the DAC
removing connection 7220 with DAC
as I understand from other threads here..

[poynton]

Originally posted by Leonar
And what about Non OS?

Hi.

Yes, a possibility !
There is a new thread started today with a small board giving the option of OS/NOS.

But first, you must get rid of the volume / remote control board !

This board looks very similar to the one I have in front of me so I will have a think and make some suggestions.

By the way, this board is used in the QUAD66 and Philips cd380

Andy

[Leonar]

The output is fairly conventional so the upgrade route follows the usual pattern.

1. remove the output muting transistors

2. Replace the standard opamps with 'better' ones eg AD826

3. Improve the power supply by replacing the diodes with faster, low noise versions and replace the standard caps with Black Gates.
4. Do not use the built in volume control - keep it at maximum
5. Remove the headphone driver amp and associated circuits.

If I find the circuit, I will post later.

I looked at the boards a bit and have the following idreas:
1. remove the output muting transistors (i think they are on the dougtherboard as indicates)

2.Replace the standard opamps with 'better' ones eg AD826
(I Like to solder a propper foot/holder where indicated on the main board)

3. I am not sure what to choose here. Any suggestion would be appreseated

4. Do not use the built in volume control - keep it at maximum
(no problem)

5. Remove the headphone driver amp and associated circuits.
(I can leave the connector disconnected (indicated on doughter board)

Questions:
1- I am wondering what this Mux is doing at the doughterboard?\
any idea?

2- Could i not connect the opamp output directly to the clinch out with a Capp and resistor (e.g. 10uF + 100) and leave out the doughterboard?

Thanking you in advance

Leonardo

[zanash]

replace rectifier diodes with 11DQ10's or better

use the very best cap that you can get to replace the output cap...some suggestions include 10 to15 stacked [parallel]1uf wima film caps [use verro board ]....these will out perform all but the very best paper in oil types.

use silver wire to take the signal from opamps to output cap and resistor network.

swap the rca sockets for a decent set of teflon insulated types

if you have not read this ......

http://www.zerogain.com/forum/showthread.php?t=9058

it could help with further curcuit and case mods