Marantz CD63 & CD67 mods list

Jump to Latest
#14,841
Hi Ray
A very Great site. Before your last post, while checking your profile I have already visited your great site. Many photos.
I must let you know a little secret: I removed the Spdif output transformer and replaced it with 300 and 75 ohm voltage divider and that caused the non reading of CDs and hence having to adjust the laser trimmer. But the output wave looked much better (will post photo later)
I wonder how they are related

Thanks and regards
 
#14,843
No, direct from RCA socket and I got the waveform as shown

With transformer bypassed and terminating with voltage divider I nice square wave
spdif.jpg
 

Attachments

  • P1020987.jpg
    P1020987.jpg
    168 KB · Views: 177
#14,845
RCruz said:
So you got better waveform transfer without the TX....
Click to expand...

No, you don't understand...

The change in shape can be caused by an incorrect measuring method, and not by removing the transformer. The first picture looks like a bad overshoot caused by an unadjusted scope probe. If you do not terminate the output properly, and use an unadjusted probe, you can't say anything about the signal.

Ray
 
#14,847
Ok 😀

Yes, the TX can be replaced by something better, but first you have to find out what the turns ratio is. Is it 1:1 or 1:2 or 2:1... Then you can pick a high frequency tranny from Pulse or Murata etc. and replace it. In the end, the output impedance has to be 75 ohm. While you are at it, change the plastic cinch socket for a decent 75 ohm BNC connector, and use a proper 75 ohm coax cable between player and DAC.

At the DAC side, the S/P-dif input should have a BNC connector as well, and the input has to be terminated with 75 ohm. The DAC can also have a crappy input transformer, so it should be replaced too. Only if the whole chain is optimized, you'll get a proper S/P-dif signal 😀.

I'll see if I can do some measurements today, to get the turns ratio.

Regards,

Ray
 
#14,849
6h5c said:
Ok 😀

Yes, the TX can be replaced by something better, but first you have to find out what the turns ratio is. Is it 1:1 or 1:2 or 2:1... Then you can pick a high frequency tranny from Pulse or Murata etc. and replace it. In the end, the output impedance has to be 75 ohm. While you are at it, change the plastic cinch socket for a decent 75 ohm BNC connector, and use a proper 75 ohm coax cable between player and DAC.

At the DAC side, the S/P-dif input should have a BNC connector as well, and the input has to be terminated with 75 ohm. The DAC can also have a crappy input transformer, so it should be replaced too. Only if the whole chain is optimized, you'll get a proper S/P-dif signal 😀.

I'll see if I can do some measurements today, to get the turns ratio.

Regards,

Ray
Click to expand...

I looked into this last year and after some investigation of the manual and googling came to the conclusion that a MURATA 76601/3C (TRANSFORMER, PULSE, 1:1; Inductance:219µH; DC Resistance:0.5ohm; ET Constant:5.5V/µs; Isolation voltage:500V rms; Winding Configuration:1:1; Turns Ratio:1:1😉 was what was needed for my CD67.

Never got round to fitting it yet though so can't defo say that it worked/made any difference.

Regards

Pete
 
#14,854
EERA :: Lecteur CD HIFI Haute fidélité - Marseille Go to "Temptation" and click on right upper "documentation" PDF. Scroll down to the image. My question is about the damping of the little spinning disk in the center of the disk sled. They have put te same damping material as is used for the case work. I have tried this but it's very hard to cut an exact circle in this stuff. I also wonder about adding weight to this piece or what happens when it's not exactly round and centered. Any one tried this and found any improvements?
 
You must log in or register to reply here.
Top Bottom