[LAU] digital upgrade of older equipment via I2S with jitter attenuating S/PDIF receiver evaluation board ??

[Niels Mayer]

It appears that others have successfully tapped into the I2S signals
on existing Envy24-based soundcards, such as the ESI Juli@ using Via
ICE 1724HT ( http://alsa.cybermirror.org/manuals/icensemble/Envy24HT091DS.pdf
 ), and have also used the technique to get improved sound out of
older digital devices:
http://www.diyaudio.com/forums/digital-source/22741-high-resolution-multi-channel-digital-interface.html
http://www.diyaudio.com/forums/digital-line-level/36252-dcx2496-mod-digital-out-x-3-a.html

The following details the simple mod for an ESI Juli@:

http://www.diyaudio.com/forums/digital-line-level/102851-i2s-juli-pci-sound-card.html

> I have an ESI Juli@ sound card ( new from ebay about $129 ) and was using the spdif to drive an external DAC in the Box. I upgraded to a used Perpetual P-3A and wanted to investigate an I2S connection. I use foobar2000 and Kernel Streaming and flac files.
> The Juli@ has an interesting design - there are two circuit boards connected by dual in line headers ( a 20 pin designated J3 and a 10 pin designated J7). The "digital" board has the PCI connection and the Envy-24 HT ( 1724 ) controller chip. The analog board has an AK4358 DAC and an AKM ADC chip as well. The "analog" board can be rotated 180 degrees to change from RCA unbalanced connectors to Balanced 1/4" Phono plugs. Therefore there are matching connectors on opposite sides of the analog board.
> I downloaded the datasheets for the Envy and the AKM DAC. The 1724 is capable of multichannel I2S outputs, and the AK4358 has multiple I2S inputs. I figured the I2S interface was going through the pin headers from digital to analog boards.
> I took a multimeter and buzzed out the connectors and the chips, and found the following signals:
> J3 ( 20 pin header )
> J3 Pin 1 -> 1724 PSDOUT[0] ( I2S data out) -> AK4348 SDTI1 (I2S data in)
> J3 Pin 5 -> 1724 PSYNC ( I2S Word Clock ) -> AK4348 LRCK (I2S Left/Right Word clock)
> J3 Pin 7 -> 1724 PBCLK ( I2S bit clock out ) -> AK4348 BICK ( I2S bit clock in )
> J3 Pin 9 - > Xilinx on the digita board -> AK4348 MCLK ( I2S Master Clock in )
> J7 ( 10 pin header )
> J7 Pin 5 -> Digital VSS ( Actually several pins on J7 are VSS )
> Here I had all the I2S signals ( Except DEEM as in Audio alchemy, but that does not exist on the Juli@ board )
> [...]
> Believe it or not, this works perfectly with the P-3A DAC. I get I2S lock and can drive it with 16/44 up to 24/96 signals. It sounds great on my system, much better than the spdif connection. The only weirdness is the P-3A phase invert light is on all the time. Maybe I need to invert the word clock or something. I may send an email to Perpetual Tech and see what they say.

......................

Same potential for Via ICE 1712 (
http://alsa.cybermirror.org/manuals/icensemble/Envy24pb1_7.pdf ) as
used on M-audio Delta series, Terratec DMX6Fire. The Delta 1010 looks
like the best bet -- find an ebay special with a failed rackmount
breakout box (the capacitors in these are known to go bad and people
get rid of them cheap) and tap directly into the DB25 connector:

http://www.diyaudio.com/forums/digital-line-level/102851-i2s-juli-pci-sound-card-2.html

> Look for a Delta 1010 (not the LT - the full version with the breakout box).
> All the I2S lines are brought out to a DB25 connector.

......................

http://www.diyaudio.com/forums/digital-line-level/152753-i2s-pc-firewire-ethernet-2.html

> [Envy24 has] I2S input I2S output all over the place.
>
> All the inputs and outputs are 'slaved' you could say together, in that they will all switch to work at one sample frequency - so you cant for example have an input working at 96khz and an output going at 192.
>
> It's easy enough to find the I2S clocks on the cards with the ENVY chips, I've done it with great success.
>
> I buffer the I2S with some logic ( http://www.nxp.com/acrobat_download/datasheets/74LVC126A_5.pdf ) , although this is for protection of the sound card more then anything else, the DAC/ADCs I've built are housed inside the PC case.
>
> The buffer has a decent output current so I'd imagine it'd be fine driving cables over a distance.

Niels
http://nielsmayer.com

PS: I think I'll start this experiment by soldering on my $0.99 Dynex
dx-sc51 since it has a total piece of crap analog section, and a
perfectly good VIA ICE1723 (
http://www.via.com.tw/en/products/audio/controllers/tremor/ ) sporting
a single i2s input (2 channels) a separate i2s output. (2 channel-6
channel), and a separate subdevice providing TOSLINK output.