non os for cdp without pcb trace cutting

[Bernhard]

Hi,

desolder the SAA7220 from the board and cut off the pins 15, 16, 18 completely.

Solder an IC socket to the board instead.

There are kind of 24pin sockets that fit into IC sockets, and they are not for ICs but for resistors. So, resistor socket ?

Solder the chip onto that resistor socket and wire pin 1 to pin 18, pin 2 to pin 16 and pin 3 to pin 15.

Plug it into the socket on the board and you're done.

This allows for fast comparison of different sound os - non os.

Just did it to my CD880 and it works.

[jean-paul]

Why not leave out SAA7220 ?? It kind of disturbs the 5V lines. Did you check how the 5V looks with and without SAA7220 ?

[Bernhard]

The DAC needs the SAA7220 clock
Or another clock.

[guido]

Connect the xtal to the 7210. If you are lucky the pcb is already prepared for that.

You can also dot that with an 7310 (smd) with 'close-combat' soldering techniques. If you look left at my avatar you can see what i mean (it is a bit blurred, but that's what it is).

mvg,

[Steve Eddy]

Originally posted by guido
You can also dot that with an 7310 (smd) with 'close-combat' soldering techniques.

Hehehe. "Close-combat soldering techniques." I like that.

A pity though as the government here has outlawed soldering irons with bayonet lugs. They consider them "assault irons."

se

[Peter Daniel]

Sa7220 is needed for digital out. You could try to just disconnect it from PS, but this affects I2S lines and the sound is much worse, when I2s lines are connected to not powered SAA7220 chip

[jean-paul]

Originally posted by Bernhard
The DAC needs the SAA7220 clock
Or another clock.

The DAC needs a quality clock anyway so why not implement it ? Try it, you'll like it. As with all cdplayers the clock quality has great influence on end results.

Originally posted by Peter Daniel
Sa7220 is needed for digital out. You could try to just disconnect it from PS, but this affects I2S lines and the sound is much worse, when I2s lines are connected to not powered SAA7220 chip

I know that but some won't need the digital out. If one insists on going non os they are better off without SAA7220.

[Peter Daniel]

Originally posted by jean-paul

I know that but some won't need the digital out.

I need it to test my DACs (and to copy CDs).

Marantz 94 has coupling transformer on coaxial output. As it supposedly not good, would it be better to use that output without any transformer at all?

[jean-paul]

Understood, that's why I use another cdplayer for copying

The transformers are bad quality but I wouldn't want to give up galvanic isolation. I replace them for better types. Some report good results without the transformer but I guess they haven't compared the original one with a good one. In that case no transformer will be better than the original one

[Bernhard]

This was meant to compare OS to Non OS, not for tuning.
I would like to built my own cdp also.