dac only works on cdrom !! why>? pls help!

[tone]

hi all,

have been running my diy dac on cdrom for quite sometime now..

the dac wont work on cdplayer digital output..
what's wrong??

pls help..

thanks.

CS8414 receiver & tda1541a nos dac.

tone.

[Elso Kwak]

Hi Tone ,
Did you put the CS8414 in the right mode= 2 (see table 3 in the datasheet)?
Check also for all three digital signals entering the DAC: WS, BCK and DATA. DATA is difficult to recognise on the scope but you must see "activity".
Good luck,

[vuki]

I would say it's something with SPDIF input circuitry. What are you using at input; transformer, active drive (buffer) or is input connected directly to receiver?

Because: CDrom has TTL level output (5V) while CD player's SPDIF output should be (and often is) 0,5V.
If you are using some kind of active circuit or transformer with wrong prim/sec ratio there could be a problem with input level.

[omar]

Originally posted by Elso Kwak
Hi Tone ,
Did you put the CS8414 in the right mode= 2 (see table 3 in the datasheet)?
Check also for all three digital signals entering the DAC: WS, BCK and DATA. DATA is difficult to recognise on the scope but you must see "activity".
Good luck,

Hi Elso Kwak ,
My 8412 is working under mode 5,
any different between mode 2 and 5?

[Elso Kwak]

Originally posted by omar


Hi Elso Kwak ,
My 8412 is working under mode 5,
any different between mode 2 and 5?

Hi Omar,
Mode 2 is for I2S outputformat used by TDA1541A, TDA1543
Mode 5 is 16 bits out LSBJ for TDA1545A, AD1851, PCM56
Mode 6 is 18 bits out LSBJ for AD1865.
All DAC's mentioned used NON-OS.
What DAC are you using Omar?

[omar]

Originally posted by Elso Kwak


Hi Omar,
Mode 2 is for I2S outputformat used by TDA1541A, TDA1543
Mode 5 is 16 bits out LSBJ for TDA1545A, AD1851, PCM56
Mode 6 is 18 bits out LSBJ for AD1865.
All DAC's mentioned used NON-OS.
What DAC are you using Omar?

Hi Elso Kwak
The next stage of my 8412 is digital filter, sm5842,
then goes to PCM1702.(It's a DIY DAC )
So I don't know if I could choose either one?
Any improvement to the sound quality?

Thanks!

[Elso Kwak]

Hi Omar,
Tone is using a NON-Oversampling DAC. That is NO digtal filter is used!
If you digital filter works with mode 5 everything should be OK.
See also the datasheet of the SM8542.

[omar]

Originally posted by Elso Kwak
Hi Omar,
Tone is using a NON-Oversampling DAC. That is NO digtal filter is used!
If you digital filter works with mode 5 everything should be OK.
See also the datasheet of the SM8542.

I got it~

Thanks!

[tone]

hi elso, the dac is in mode 2

as for the input circuitry: 0.1uf-pulse transformer ratio 1:1-75R to grd.

vuki: yes cdrom has TTL spdif output 5V..do i need to convert to anything else as for cdplayer digital output?

thanks

tone.

[vuki]

Hi tone,

why don't you try it without input transformer? Then you'll know what next. If it works without xformer I suggest you to make active drive for receiver (a differential one with 74HCU04 and 74HC86) and forget the xformer.