sm5842 + 2xpcm63 dac

[apolon34]

Hi everyone,

I'm designing a new dac for my cd-pro2 drive. I will feed the dac directly with i2s coming out from the cd-pro2, thus avoiding the i2s/spdif and spdif/i2s conversion.

here's the schematic:
http://belinfabien.free.fr/dac/pcm63/pcm63.png

the pcb:
http://belinfabien.free.fr/dac/pcm63/typon%20pcm63.png

the eagle files:
http://belinfabien.free.fr/dac/pcm63/eagle/

please comment. I took example on doede dac1 but using pcm63, like in guido tent's dac.

[apolon34]

up

no comment on this design?

[dddac]

You might wonder why no body is reacting here

There are many threads with hundreds of dicussions on many parts of the design you showed us here, like power supply, the way you designed your pcb, the digital filter vs NOS etc etc....

Still no reactions. I am puzzled too. I did look at the design and what came to mind is that it is evident you have spent a great deal on the power supply, which I think is important too.

Though a few questions:

You are using small coils to filter thze power supply. Have you considered to use them at the output to the IC's to make sure the IC sees high impedance towards to the power supply?

Are you using a low Jitter clock, like the Tent or so? This makes a difference too.

I see no termination of the Output from the PCM63. How are you terminating? I expect passive I/V ?

What type of Electrolytes are you using ? BG's or similar or normal stock ? Here gain is to be made...

For the rest this for sure will be a good sounding DAC, regardless of small details, my experience is, that this combination just sound very good.

Hope you will get some other inputs too

Doede

[apolon34]

Hi dddac,

Thanks for your reply !

for the psu I'll use coils between the global psu (about 10-12v) and the regulators to avoid switching noise to polluate it. Since I have a regulator per IC, I thought it wasn't necessary to put coils in it. If you say it'll better, I'll add it.
At least I can make place for it on the pcb and strap if it isnt't better.

For the clock, I will use a tentlabs XO.

for the I/V stage, I have 2 separates boards to test. One is super-pair I/V and the other is a tntaudio output stage with passive I/V + amplification.

the schematic is here: http://www.tnt-audio.com/clinica/tnt1541_e.html

The electrolytics will be bc136 or os-con I think.

I saw that you've build a pcm63p dac too. How does it sound compared to tda1541 ?

thanks

[ggta]

Hi Apolon

I'm also interested by this design.

No more comments?

[apolon34]

I've updated schematic and pcb. I made a ground plate on top with max surface and route the signals on the bottom.

it should be ok now...
any comments ?

[rfbrw]

Originally posted by apolon34
Hi everyone,

I'm designing a new dac for my cd-pro2 drive. I will feed the dac directly with i2s coming out from the cd-pro2, thus avoiding the i2s/spdif and spdif/i2s conversion.

Do you have a controller for the CD Pro2 DSA interface ?

[apolon34]

yes, i use a pic 18f452 to control the cd-pro2, IR and a VFD display.

[rfbrw]

Originally posted by apolon34
yes, i use a pic 18f452 to control the cd-pro2, IR and a VFD display.

I assume then you can change the default digital audio format of the module as the SM5842 does not accept I2S as an input format.

[apolon34]

I thought it would take I2S directly...

the sm5842 datasheet says, when inf1n is low, that it accepts "LR alternating, trailing data".
IW1n and IW2N are high so it accepts 16 bits input.

i2s seems right or did I made a mistake ?

thanks