CD723/753 tweaking!

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Are these the 270R, the 100R and the 150p we are talking about with this mod!?
 

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Apologies

Hi all, I have to hold my hand up and apolgise for that mistake on Decibel Dungeon.

I think that is was Massimo who pointed it out to me originally and I changed the text but must have forgotten to upload the corrected file.

Anyway, it is corrected now.

While I'm here, I have to tell you that Chris Found who supplied those mods for the CD723 has decided not to continue with this CD player ( he's working with a DVD-A player now) so there will not be a follow up article unfortunately.

If anybody does come across additional mods for the CD723, I would be pleased to add them on my site. Of if you have a radically modified CD723 and have pictures, I would be pleased to link to them (or even host them on DD).
 
Audiofanatic said:
Hi Audio tweakers,

gpapag and I (AF), want to start a new thread about tweaking the PHILIPS CD-723/753 CD-Player's.

I'll try to dig-up the schematic within a few days and hope that I'll be able to buy a scanner in this weekend so we all will know what we can do, and how we can do the modifications to this great and cheap CD-Player.


Best Regards,

Audiofanatic!;)
Hi Guys,

I couldn't find the schematics yet, 6th box and still no schematic.
I'll try again next week 7 boxes to go, perhaps the last one first?

You'll hear from me soon.

Regards,

Audiofanatic
;)
 
Hi All,

Good idea guys. I have a CD723 and I'm very very happy with it using opa2132 now for the analog out. Let's hear it from you, what should we do with that horrible tda1545? Any idea how to make it a low jitter, NOS parallel TDA1543 or TDA1541 DAC? discrete output stage some nice power supplies.etc etc. ohhhhh dreaming allready.. keep me informed..
gr,
Thijs
 
Hi Jean-Paul,

Your right about the TDA1545 statement.. it's a bit provocative :devily: .. actually the TDA1545 sounded OK, better than my TDA1543 NOS... but compared to my Crystal DAC the TDA1545 sounds just OK, but it looks terrible on the scope, lot's of noise, 4x(?) ovresampling easely visible on the scope. I don't think a TDA1543 would be a upgrade, but maybe a parralel TDA1543 is?

gr,
Thijs
 
I have no experience with 1543 but I have 1545 in my Philips CD721. I've listened to a lot of expensive CD players, but I'm not sure they perform better than my modified Philips. If they do the difference is like between CD players that belong to the same class.
What I found out is that the performance of the 1545 depends a lot on the PSU and the caps near it. I use a 10uF MKT one.
In case there is a 7805 chip in the CD723 (there probably is) you should replace it with 317 (the change is easy adding a small PCB). You will have more and tighter bass. An AC filter and schottky diodes in the PSU are a must. After that listen to your TDA1545 again. Maybe you’ll hear the difference, but that depends on the rest of your system too.

Regards
 
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Joined 2002
You're right about the TDA1545 statement.. it's a bit provocative .. actually the TDA1545 sounded OK, better than my TDA1543 NOS... but compared to my Crystal DAC the TDA1545 sounds just OK, but it looks terrible on the scope, lot's of noise, 4x(?) oversampling easily visible on the scope. I don't think a TDA1543 would be an upgrade, but maybe a parallel TDA1543 is?

Hi Thijs, did you measure this on the output or on the supply ? And did you check the ground routing in the specific machine ? Does it have stopper resistors in the datalines ? Can a better 5 V supply be a solution ?

I am not very familiar with the 721/723/753 Philips cd players as you can see. My experiences with the "newer" Philips or Marantz cdplayers while modifying them are not too positive from a mechanical point of view ( CD36/CD38/CD63/CD4000 etc. ). But what else can you expect for that price ? Especially the PCB material is weak and that's why I avoid them while I can. Sound is OK though. With some of the models even very OK.

Never done an A/B comparison between the two DAC's but the TDA1545A is able to convert 16 bit for sure. The TDA1543 is not fully 16 bit. IMO the TDA1545A isn't that bad. The technique used in this chip comes from the TDA1541A. Since I have a weak spot for this fantastic DAC chip it's next of kin is worth trying out.
Just for my own curiousity I am designing a PCB around TDA1545A.

actually the TDA1545 sounded OK, better than my TDA1543 NOS.

Although dangerous to believe instantly I read a few times before that results with TDA1545A are better than with TDA1543. I am glad to read from you that your experiences are the same.

Paralleling DAC chips is not my cup of tea so I don't comment on that.

Regards,

Jean-Paul

Datasheet TDA1545A: http://www.semiconductors.philips.com/acrobat/datasheets/TDA1545A_T_3.pdf
 
About this resistor mod in the digital output:

I did remove the 2 parts as told and shortened the one resistor.

As i mentioned before i use my CD753 only as transport and this mod
definately makes the coaxial output sound worse, dirty sounding here!

I still don´t know what resistors these are and what they are doing.
The values are ~220 for the 3896 and ~160 for the 3897 in my circuit.

What brought a small benefit was removing the capacitor from the
coaxial plug to ground.
 
Mains filter

Asen said:
I have no experience with 1543 but I have 1545 in my Philips CD721. I've listened to a lot of expensive CD players, but I'm not sure they perform better than my modified Philips. If they do the difference is like between CD players that belong to the same class.
What I found out is that the performance of the 1545 depends a lot on the PSU and the caps near it. I use a 10uF MKT one.
In case there is a 7805 chip in the CD723 (there probably is) you should replace it with 317 (the change is easy adding a small PCB). You will have more and tighter bass. An AC filter and schottky diodes in the PSU are a must. After that listen to your TDA1545 again. Maybe you’ll hear the difference, but that depends on the rest of your system too.

Regards
Hi Asen,
I can second the AC filter. Voices improved considerably with the filter implemented.
I have not yet installed the Schottkeydiodes in the powersupply of my Philips CD-650 but in my old Sony they improved the sound a bit. My experience with the TDA1545A vs the TDA1543 in my KWAK-DAC is that the TDA1545A sounds more like the TDA1541AS1. The TDA1543 is more like the AD1865N-K but without the listener fatigue.
For the unawary please note:
TDA1543= Philips I2S format.
TDA1545A = Sony/BB format.
AD1865N-K = Sony/BB format.

Just my subjective impressions of course ;) ;)
 
Hmmmmmm :confused: ..I did remmember just slightly that there was something with the digital format back when I looked up the TDA1545.. can somebady help me with this sony/BB versus I2S format? Can a digital receiver like the CS814 be adjusted to these formats?

gr,
Thijs




PS thanks for the datasheet, from the datasheets it looks like a prommesing chip, does anybody know wether it is availeble somewhere?
 
Elso Kwak, intresting reading.

I have a sony x5000 with cxd-2515, and im on final stages of my NOS (tda1541a) dac. I have seen your digital interface that you recomended in the digital transformer thread.
Would you recomend me using it as an alternative to regular transformer? I have the schematics for the 2515.

Also, what setting would you recomend on the CS8412 (M0,M1,M2,M3) for use with that dac/transport?

regards - kasra:)
 
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