CD723/753 tweaking! - Page 19 - 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 15th October 2012, 07:37 PM   #181
diyAudio Member
 
Join Date: Nov 2011
Only what I can say: the CD753 is excellent sound even in stock form.With some few mods this player is really amazing ! I had one, and really I regret selling this machine. , BUT I met the Marantz, the CS4392 audio dac ,etc. and I'm happy with them... for the moment
  Reply With Quote
Old 13th January 2013, 09:43 PM   #182
Eldam is offline Eldam  France
diyAudio Member
 
Join Date: Sep 2012
Location: At home, sweet sound home...
Hi everybody,

I'm tweaking a CD723 in a low-cost way for pleasure. I Just have another PS for the AOP (maybe a 2604 cause i have it or another if I go with passive I/V between AOL/R and Vref. Don't want to go with discrete here...

I plan to feed the TDA1545a like that on the original PSU (in red: added parts): main powersupply/diodes -> 4700 uf standard -> 0r7 -> 7805 reg with a diode to adj (=5,6 v) -> 100 nf MKT -> 100R (to make resistive output?) ->1F supercap (esr=30homs; ripple killer? & as a virtual batery to flat impedance curve) -> very low esr cap 47uF (smd Panasonic SEPC : hope to be as good as larger SEPC Sanyo can type?) at the pins of the TDA 1545a... perhaps with 100 nf smd ceramic (or/and 10 nf ?). (the rail is + 5,5 V)

Is it good to do the same for Iref (same reg but feed TDA via 15k R -> 47 uf -> 10k R -> Iref (pin) ?

May-be a pi between the 4700 uF / 07R with > 6000 uF very low esr computer board style sanyo AF before the 78005 reg ?

In my non tech "brain", the supercap is like a firewall and a big source without ripple for feeding after the low esr 47 uF cap which supply tda1545. Is it good or the original simple 200 uF is enough ?

I just want to use caps, resistor or mini inductor like Neosid...?!. I will just change the diodes for ultra fast and remove their original // caps.

Thank you in advance for your inputs for "my ultimate cd723 3 bucks tweak" , my main source is a DAC with a streamer. I would like a redesign to cost here.

cheers,

Eldam
  Reply With Quote
Old 16th March 2013, 02:12 PM   #183
Chivvyp is offline Chivvyp  United Kingdom
diyAudio Member
 
Join Date: Apr 2006
Location: London
Default CD48 clock feed

Hi,

I've been modding a marantz cd 48, marantz version of philips 751, ealier version of 753.

I'd done some cap replacements etc. and it was sounding good so I decided to fit a new clock which is where it all went wrong. The cd doesn't spin at all when it powers up and screen shows no disc so I assume the clock signal isn't being picked up?

The standard clock circuit is in the picture, I removed all the bits
3114
5100
1101
2112
2113
2114
3117
and connected the clock to the CRIN pin 13. Did I remove too much?

I'm using a flea with a tent xo. Flea seems to be producing 5v correctly and I can trace continuity from output to CRIN, don't have an oscilloscope to check the clock output though (but it's a new xo).

Anyone got any suggestions?

Pete
Attached Images
File Type: jpg cd48.jpg (20.3 KB, 137 views)
  Reply With Quote
Old 17th March 2013, 01:07 PM   #184
Chivvyp is offline Chivvyp  United Kingdom
diyAudio Member
 
Join Date: Apr 2006
Location: London


I didn't have the flex connector plugged in. What an idiot!

However, it's still not working, the disc still doesn't spin at all.
  Reply With Quote
Old 5th September 2013, 04:51 PM   #185
tomst is offline tomst  United Kingdom
diyAudio Member
 
Join Date: Nov 2011
My self and a friend are trying to get some improvements out of his old CD4000 (same as the cd723) From reading this and other threads it seams the best OPAmp for this is the LME40720/lm4562 or OPA2604. At some stage later we will be working on the power supply. But for now i just want to clarify how to implement the OP-Amp properly with regards to the DAC and what can I done wit the DAC.
also from reading other threads the is notes on change the DAC out put current and adjusting for Fs (Full Scale) So far I have removed the muting circuit and added some Poly prop capacitors and some better phono connectors. I have the service manual for the CDPlayer and the data sheets for the DAC and OPamps.
Attached is the dac I/V stage of the player.

Thanks
Tom
Attached Files
File Type: pdf CD4000_doc (dragged) 2.pdf (389.8 KB, 18 views)
  Reply With Quote
Old 9th September 2013, 07:14 AM   #186
diyAudio Member
 
Join Date: Dec 2001
Location: Eindhoven
Quote:
Originally Posted by Chivvyp View Post
Hi,

I've been modding a marantz cd 48, marantz version of philips 751, ealier version of 753.

I'd done some cap replacements etc. and it was sounding good so I decided to fit a new clock which is where it all went wrong. The cd doesn't spin at all when it powers up and screen shows no disc so I assume the clock signal isn't being picked up?

The standard clock circuit is in the picture, I removed all the bits
3114
5100
1101
2112
2113
2114
3117
and connected the clock to the CRIN pin 13. Did I remove too much?

I'm using a flea with a tent xo. Flea seems to be producing 5v correctly and I can trace continuity from output to CRIN, don't have an oscilloscope to check the clock output though (but it's a new xo).

Anyone got any suggestions?

Pete
You can check the DC voltage at the clock output, that should be about 2.5V. Also, check if you have connected the clock to the original crystal input (rather than the output).

best

Guido
__________________
Guido Tent
www.Tentlabs.com
  Reply With Quote
Old 9th September 2013, 08:12 AM   #187
Chivvyp is offline Chivvyp  United Kingdom
diyAudio Member
 
Join Date: Apr 2006
Location: London
Thanks Guido,

To be honest I gave up on this. I put all the original parts back in and it still didn't work so I scrapped it.

I'm now using the flea as a 5v supply to feed the dac in my CD5000.

Regards

Pete
  Reply With Quote
Old 26th September 2013, 08:35 PM   #188
210 is offline 210  Germany
diyAudio Member
 
Join Date: Dec 2010
Location: Here
It's possible to reduce the very high headphone level (5Vrms) by about 5 dB with changing R3605 and R3606 from 10kOhm to 33kOhm.
This will also balance the + and - input resistances seen by the headphone-OP.
__________________
You know that's it: receive and transmit (Peter Gabriel
  Reply With Quote
Old 26th September 2013, 08:44 PM   #189
210 is offline 210  Germany
diyAudio Member
 
Join Date: Dec 2010
Location: Here
Bypassing the outputs with notch-filters (12mH/80mA/40ohm/SRF380kHz in series with 68pF/160V/Styroflex or mica)
significantly reduce the strong 4fs (176kHz) aliasing.
A 20kHz sinus then looks cleaner on a scope.
__________________
You know that's it: receive and transmit (Peter Gabriel
  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


Similar Threads
Thread Thread Starter Forum Replies Last Post
A new clock mod for cd723 apolon34 Digital Source 2 27th November 2004 11:17 PM
Philips CD723 secanbj Digital Source 2 9th March 2004 11:11 AM
Anyone tried battery operation on CD723 ? Heiko Digital Source 0 2nd December 2003 02:36 PM


New To Site? Need Help?

All times are GMT. The time now is 04:58 AM.


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