CD723/753 tweaking!

[Guido Tent]

hi Guido

OK but does it work for TDA1545A as in my CD723 ?

does it matter that, apparently, I will be doubling the frequency of BCK.

where can I get details about your clock cct ?

do you do a cct board for it ?

all my cd psu's are batteries - sounds nice. Would you recommend any additional regulation after the battery for your clock cct ? ( apart from a good quality cap )

cheers

mike

Hi

I do not know the 1545, but you may compare both datasheets. Mail me offline for more info on clocks.

Yes, I recommend additional regulation.

best regards

 

[TimA]

CD723 I/V op-amp

I have recently been using two NE5534s as I/V in the CD723 with very good results, but as the NE5534 (without compensation capacitor) is not stable at unity gain can anyone please offer advise regarding the suitability of a non-unity stable opamp for I/V in the CD723 circuit?

Many thanks for any help,
Tim.

 

[jean-paul]

NE5534 again !?!?

OPA627 is unity gain stable and excellent sounding. You can remove the caps that are needed for keeping NE5534 stable at unity gain. Since you really need a dual opamp AD826 or LM6172 might be a better choice.

But maybe I misunderstood you post !?!?

 

[TimA]

CD723 op-amp stability

Jean Paul,

Thankyou very much for help.

Are you saying that the NE5534 (that is not stable at unity gain) will be stable in the CD723 as I/V. If so, could you please explain to me why this is so, for example is there enough gain in the circuit to prevent instability with the NE5534, or is op-amp stability for I/V not relevant, if so why?

Yes, I have tried the OPA627 and LM6172 but surprisingly I prefer the sound of the NE5534 (biased into class A) in most respects!

I would like to understand the requirements of the CD723 circuit with regard to op-amp stability. If you have time to explain briefly I would be most grateful.

Many thanks,
Tim.

 

[jean-paul]

Too late now, maybe tomorrow when time permits. When NE5534 sounds better than OPA627 there must be something wrong in your cdplayer

 

[mikelm]

Hi Tim,

From your postings here and elsewhere it seems that we similar CD and amps - modified cd723 & a version of JLH simple class A.

I would be interested to compare ideas and perhaps equiptment sometime.

I live in the north but my family are in the south so I come down quite often.

cheers

mike

 

[weng]

Philips CD721

hi,

my philips cd721 quit playing today. it only shows "NO DISC" when a cd is inserted and thats it.

is this problem repairable? tried good/new cd and still the same problem persist. any tricks to tinker inside to make the cd working again?

thanks

 

[Nuuk]

Did it just stop working or have you done any mods recently?

 

[weng]

hi nuuk,

no mods has been done to this cdp. just quit on me a couple of days ago.

 

[Nuuk]

Ok, this is a long shot but you may as well try it. Remove the lid and you will see the transport assembly on the left side of the case. Look at the plastic cradle that is screwed to the chassis (usually only by two screws at the rear). Turn these two screws anti-clockwise by half a turn and then try it again.

 

[weng]

i can't find the screw maybe u can point me out where it is.

An externally hosted image should be here but it was not working when we last tested it.

thanks

 

[Nuuk]

Hmmmm. It's a different transport!

This is the one in the CD723.

An externally hosted image should be here but it was not working when we last tested it.

The yellow line points to one of the screws that fixes it to the chassis. There is another one on the opposite side.

There must be something similar holding your transport in position!

 

[weng]

nuuk,

can't view ur pic. pls repost

thanks

 

[singa]

RE: "no disc"

Hi Weng,
THe 721 is using CDM12.1 laser assembly and the 723 sports the VAM1202 laser.I hear the 1202 laser module can also be used for cdm12.1.It's most likely that the laser has died.Try replacing it.

 

[Nuuk]

Weng, did you see the picture yet? There was a problem with my ISP and the picture didn't appear for a few hours.

 

[weng]

singa,

thanks for the info.

nuuk,

saw the pic already. it seems that the lens of my transport doesn't emit any light. the lens must be dead or something

 

[chatziva]

Hi All,

I am going to ask a basic newbies question !!

I am new to the world of DAC's. I have a CD723 which I want to use as a transport for my DAC. The DAC i have is the OPUS from Twisted Pear Audio. What I'm struggling with for a while now is to find a way to interface the two

As far as i understand one option is to feed the DAC directly with I2S signal from the CD723, but I suspect that will not be easy?

Another option would be to feed the DAC with SPDIF signal (Twisted Pear Audio also do a SPDIF to I2S receiver) but is the digital output on the CD723 an SPDIF interface? (sorry i am a newbie - i don't understand whether the term "digital output" and "SPDIF" is the same)

So i guess my question in a few words is ... how exactly can i use the cd723 as a transport with my OPUS DAC?

It seems that a lot people know how to do this trivial thing but I am struggling to find any explicit guidance ( i guess I could ask Twisted Pear Audio too!

Thanks

 

[TimA]

The digital output on the CD723 is SPDIF.

Tim.

 

[rbroer]

The digital output on the CD723 is non-bit perfect SPDIF , which makes it a bad choice for a transport.

 

[Andypairo]

The digital output on the CD723 is non-bit perfect SPDIF , which makes it a bad choice for a transport.

This is true, unless you "hack" the player.
Using the hacker you can select oversampling rate and data format (EJAI or IIS) and eventually fit a TDA1541A inside as I did

Cheers

Andrea