Marantz CD63 & CD67 mods list - Page 1891 - diyAudio
Go Back   Home > Forums > Source & Line > Digital Source

Digital Source Digital Players and Recorders: CD , SACD , Tape, Memory Card, etc.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 13th December 2012, 10:06 AM   #18901
diyAudio Member
 
Join Date: Oct 2012
Quote:
Originally Posted by 6h5c View Post
Hi,

Basically, you are bypassing a large section of the analog low-pass filter with this mod. That means lots of high-frequency noise from the DAC can enter your system. This is not a good thing, but the effect of it may vary from system to system. Some have reported a better sound because the extra opamp stage is bypassed, but it can also get worse and cause more distortion. So YMMV... and watch your tweeters!

Ray
@Ray: You are most probably right but since I will use +/- 15V low noise voltage regulators for the analog rail and the low jitter clocks are having their low noise regulators I think noise might not be a big issue here even if the LPF is taken away. Someone has also told me that the SQ would be more neutral and non colored if the LPF is removed. I will test it out and see if that was the case.

BTW I have assembled the two Fleas from you and this will be used in my 63SE and the CDP will be used in the bed room for my headphone amp. I will start the new mod project after Xmas.

One thing I want to seek your view, Ray. In my modded CD63 KI since I have removed everything after the opamps and when I switch off the CDP there is always cracking noise feeding to the amplifier. Everytime I need to switch off the amp. first then turn off the CDP to avoid this disturbing noise. Do you have any simple cure for this and not affecting the SQ ?

Last edited by higlander; 13th December 2012 at 10:20 AM.
  Reply With Quote
Old 13th December 2012, 11:02 AM   #18902
6h5c is offline 6h5c  Netherlands
One Seriously Addicted to Audio and Electronics
diyAudio Member
 
6h5c's Avatar
 
Join Date: Apr 2004
Location: Heerhugowaard
All those low-noise regulators will not help against the high-frequency square wave that is output by the DAC itself... it's the nature of the beast, so to speak.

The analog filter is needed to create a sinewave shaped signal out of this pulse-width modulated output, because it's nowhere near analog. If you bypass the filter, all kinds of higher-order harmonics will enter the system and this will create all sorts of distortion and intermodulation products. Not good...
But, depending on the system, you may or may not hear the negative side-effects of this.

The solution for the switch-off noise is a muting relay. You can find more info on this on my CD57-XXL page.

Good luck with The Flea's

Ray
Attached Images
File Type: jpg PWM.jpg (66.8 KB, 164 views)
__________________
Gonna buy my little girl a pink soldering-iron
The new DOS-CFP board is out!
  Reply With Quote
Old 13th December 2012, 03:10 PM   #18903
diyAudio Member
 
Join Date: Oct 2012
Thanks Ray for the valuable advise and I will try to construct the muting circuit when I have the time.

In my KI mod I tried to feed the 16 MHz clock signal directly from the clock to the Decoder via C521. Unfortunately the CD was unable to read any tracks and started to spin by itself. I have no idea what has gone wrong . I used the same clock output to both DAC and Decoder (in parallel). Even though I added a 100ohm resistor to the cable connected to the Decoder the result was the same. Do you have any advise on this please Ray ?
  Reply With Quote
Old 13th December 2012, 03:25 PM   #18904
6h5c is offline 6h5c  Netherlands
One Seriously Addicted to Audio and Electronics
diyAudio Member
 
6h5c's Avatar
 
Join Date: Apr 2004
Location: Heerhugowaard
It should work with a small capacitor in series. IIRC, the decoder's clock-input has some DC offset that may screw things up. Did you disconnect the PCB trace between the DAC's clock output and decoder properly?
__________________
Gonna buy my little girl a pink soldering-iron
The new DOS-CFP board is out!
  Reply With Quote
Old 13th December 2012, 04:49 PM   #18905
diyAudio Member
 
Join Date: Oct 2012
Quote:
Originally Posted by 6h5c View Post
It should work with a small capacitor in series. IIRC, the decoder's clock-input has some DC offset that may screw things up. Did you disconnect the PCB trace between the DAC's clock output and decoder properly?
Thanks Ray. BTW what is IIRC ? What I did was to connect the clock cable to one leg of C521 on top of the PCB and cut its leg on the side connecting the DAC. See the uploaded diagram.
Attached Files
File Type: pdf CD63KI_doc.pdf (143.6 KB, 20 views)
  Reply With Quote
Old 13th December 2012, 04:54 PM   #18906
diyAudio Member
 
Join Date: Oct 2012
Oh, I know IIRC means "If I Remember Correctly". Initially I thought it was something realted to capacitors that you had mentioned

Last edited by higlander; 13th December 2012 at 05:17 PM.
  Reply With Quote
Old 13th December 2012, 07:07 PM   #18907
diyAudio Member
 
Ben Hanke's Avatar
 
Join Date: Dec 2007
Location: Vancouver, BC
Send a message via MSN to Ben Hanke Send a message via Skype™ to Ben Hanke
I just fixed my buzzing problem by moving the centre tap of the output stage transformer from U309 to here:

Click the image to open in full size.

I can't rule out the possibility that it was just a bad connection before. Thanks for spurring me to take another look, higlander - that's been bugging me for a while.
__________________
Modified Marantz CD63KI -> Modified PM66KI -> B&W 805S
  Reply With Quote
Old 13th December 2012, 08:07 PM   #18908
diyAudio Member
 
Join Date: Oct 2012
Quote:
Originally Posted by Ben Hanke View Post
I just fixed my buzzing problem by moving the centre tap of the output stage transformer from U309 to here:

Click the image to open in full size.

I can't rule out the possibility that it was just a bad connection before. Thanks for spurring me to take another look, higlander - that's been bugging me for a while.
Hi, it is really nice to hear that eventually yo have solved your long lasting problem. I am sure your CD63 is now very quiet. Actually I am now enjoying my KI while typing
  Reply With Quote
Old 13th December 2012, 08:09 PM   #18909
diyAudio Member
 
Ben Hanke's Avatar
 
Join Date: Dec 2007
Location: Vancouver, BC
Send a message via MSN to Ben Hanke Send a message via Skype™ to Ben Hanke
Me too
__________________
Modified Marantz CD63KI -> Modified PM66KI -> B&W 805S
  Reply With Quote
Old 13th December 2012, 08:51 PM   #18910
6h5c is offline 6h5c  Netherlands
One Seriously Addicted to Audio and Electronics
diyAudio Member
 
6h5c's Avatar
 
Join Date: Apr 2004
Location: Heerhugowaard
Quote:
Originally Posted by higlander View Post
Thanks Ray. BTW what is IIRC ? What I did was to connect the clock cable to one leg of C521 on top of the PCB and cut its leg on the side connecting the DAC. See the uploaded diagram.
No, it has nothing to do with caps

Looks o.k. to me, it should work this way... Did you also connect a GND wire from the Flea to the decoder?

Maybe C522 and 523 should be removed. It's the last thing I can think of. Especially that 10nF is quite a capacitive load.
__________________
Gonna buy my little girl a pink soldering-iron
The new DOS-CFP board is out!

Last edited by 6h5c; 13th December 2012 at 09:01 PM.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



New To Site? Need Help?

All times are GMT. The time now is 08:59 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2