Cd Drive Or Player With I2s Out

pentode1

Member
2007-12-24 10:25 am
I am in the middle of building an Audio Note Dac1 but want to try bypassing the spdif input/cs8416 and connecting via I2S.

Is the Philips Cdpro2lf still available?

Alternatively are there any cd/dvd drives or players with an I2s output.

(I have an Arcam Cd72 but can't find out anything about which CD mechanism it uses)

P
 

pentode1

Member
2007-12-24 10:25 am
I removed the Sony drive mechanismfrom the CD72 and downloaded the data sheet for the Sony CXD2585Q controller.

The pcm data out, L/R word select and bitclock outputs are on pins 66, 65 & 67 respectively. I will locate these on the Cd72 main pcb.

So I will try connecting these to the sdata, LRclk and sclk pins on the CS8416 socket (with it unplugged but the 74HC02 in circuit as it is required to drive the AD1865) and see what happens!

P
 

pentode1

Member
2007-12-24 10:25 am
Further thoughts & AN Dac1.1

I have located the I2S connections on the Arcam pcb and fed them to a mini din socket.
But there is a fly in the ointment! .
The Sony drive transmits in 24bits 2's complement msb first format of which the first 16bits are the pcm audio. (This explains why I measured the bit clock at 2.11Mhz = 48 x fs)
But the AD1865 requires 18bits 2's complement msb first.

So I plan to use a Atmel At Tiny44 mcu running at 20Mhz to gate the bit clock after 18bits have been counted. (The AD1865 can accomodate a gated clock) It's easier and more flexible to use the Tiny44 than glue logic, with the L/R clock being used the start the counters.

For now, the Dac1.1 kit is up and running via spdif.
I am surprised at the amount of extra detail and clarity that is audible even though its not yet burned in. Considering that there is no analogue filtering at all, I was expecting some audible artefacts but the valve out put stage and my valve power amp driving only the ribbon tweeters of a pair of Dali Icon2s help. (A Denon 1906 av amp in direct mode drives the mid/bass drive units and active subwoofer)

(I did add a dedicated analogue supply to the Dac1.1)