Hijacking I2S _ What CDP or DVD?

[Pano]

Hey guys - I'm looking for an inexpensive CDP or DVD/CD out of which to hijack the I2S signal.

I'm toying with some IR transmission of the I2S bus using stuff made by InfraCom . Basically it transmits up to 4 channels of I2S via diffused infrared. Works like a charm, too.

So I need to find a cheap and easy player to hijack the I2S signal from. Something current that can be found online or retail in the US would be perfect.

Any ideas? Anyone got one they've hacked and would suggest? I was going to use my old Apex, but it died before I could.

Thanks

 

[ejaouen]

SIMPLY GREAT !!!!!!!!!!
This Infracom chips solution is very interesting ! For people like me looking for PC to DAC solution with native electrical isolation from the pc !

 

[acid_k2]

In almost all CD or DVD player, with a separate DAC chip, you can tap I2S signals. In oldest units that should be simplier.

 

[Pano]

Yes, easier in the older, less intergrated units.

I was hoping someone here would have tapped the I2S in a recent player. Maybe not....

 

[rossl]

The Oppo 981 has this nice connector location with labels.

It's right next to the Cirrus Logic DAC chip.

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

 

[Pano]

Well, will you look at that! Bingo!

I do like the Oppo players. Was hoping for cheaper (like dirt cheap), but may not find it. Thanks Ross.

 

[amc184]

For getting I2S I would go for an older Philips (or Philips based) model. Most of these will have I2S accessible from through hole components, and these player's chipsets are well documented.

eBay has a few suitable candidates, like listing No. 170336068042, No. 120426908928 and No. 150346673208.

There are a few pitfalls to avoid if you want to use new players. I don't agree with this comment:

In almost all CD or DVD players, with a separate DAC chip, you can tap I2S signals.

A lot of CD players may use a separate DACs, and hence some sort of internal digital link, but not necessarily a link using the I2S format. Most players using AKM, Burr-Brown, Texas Instruments, Sony or Analog Devices DACs will be using other formats (EIAJ, simultaneous etc.).

The other pitfall is that many modern players will be using more integrated chipsets, and often you won't be able to access an internal digital signal until after it has been oversampled and filtered, and these integrated filters often have pretty dismal performance.


Ideally though, you'd have the same player as me, an Arcam Alpha +, which has I2S via an unpluggable cable 🙂 .

 

[acid_k2]

A lot of CD players may use a separate DACs, and hence some sort of internal digital link, but not necessarily a link using the I2S format. Most players using AKM, Burr-Brown, Texas Instruments, Sony or Analog Devices DACs will be using other formats (EIAJ, simultaneous etc.).

Amc184: I agree with you, but EIAJ fomat (aka Japanese or Sony) can be converted to I2S with some really simple logic. I've wrongly assumed that we can TAP I2S signal for almost all players, but in real life we can easily OBTAIN I2S signal for almost all players (with separate DAC --> older units)...
Simultaneous data format is unkown to me for audio DAC, do you have some data/example/weblink for that?

 

[amc184]

Simultaneous is where you've got separate left and right channel data lines. Lots of DACs support it (the TDA1541 is the first example that springs to mind), especially mono ones.

Yes, some other formats can be converted to I2S, but some can't (at least without a whole lot of hassle), especially simultaneous and LSB first formats.

Anyway, I would still recommend going for a Philips player, specifically one using a SAA7210 or SAA7310 decoder. Yes, some formats can be converted to I2s, but it is probably easier not to.

 

[Pano]

Thanks for the tip on the Philips players. That is probably what I'll do.

Also have a couple of cheap little USB DACs based on the CM108 chip. It provides IIS out - if I can get to the pins.

 

[jkeny]

What about one of those Networked Media Tanks? Something like a Popcorn Hour?

Here's what I came up with - the chips inside are:
http://www.networkedmediatank.com/showth...p?tid=9051
Hardware HDX 1000
* Processor : Sigma Designs SMP8635 Rev. C
* DDR DRAM : 64-bit 512Mb
* External NOR Flash : 16-bit 256Mbit
* LANCHIP: REATEK RTL8201CP
* Audio D/A CHIP: AKM AK4420ET
* HDMI 1.3 CHIP: SILICON IMAGE SIL9134CTU
* SATA TO USB: JMICRON JM20330
* USB SLAVE : CY7C68300C-58 LFXG07

So if we look at the datasheet for the AK4420 DAC chip - the input pins that we can tap I2S off are:
Pin 4 = MCLK (The Master Clock) goes to our DAC input pin named BCK
Pin 6 = SDTI (The Data Stream) goes to our DAC input pin named DATA
Pin 7 = LRCLK (The Word Clock) goes to our DAC input pin named WS

Multi channel I2S tapping is a bit more difficult - the SIL9134CTU (HDMI chip) was difficult to find a datasheet for but I eventually found this: http://receiverfaq.ru/1/yamaha/RXV663.pdf
A schematic for

On Page 5 you will find the SIL chip and the I2S inputs are
pin 5 = MCLK (the Master Clock)
pin 6 = SD3
pin 7 = SD2
pin 8 = SD1
pin 9 = SD0 - all these are the I2S Data pins
pin 10 = WS (The Word clock)

These 4 I2S data streams could be fed to a SABRE32 DAC for superlative audio output!

I know Rossl has one of these, I wonder has he tried anthing like this?

 

[rossl]

The SPDIF out of the Popcorn Hour sounds excellent when fed to a Sabre DAC, so I haven't bothered trying to tap the I2S directly.

It would be an interesting project to build a box with a Popcorn hour, hard drive and Sabre DAC all integrated together, but I haven't done that yet.

I traced the SPDIF output on the Popcorn Hour circuit board. It comes out of the Sigma CPU chip, goes to a two resistor voltage divider and is capacitor coupled to the RCA jack. I thought about modding that with a transformer, but the resistors and cap are EXTREMELY small surface mount parts.

 

[jkeny]

Good to hear that the PCH sounds good when fed to the Sabre (I guess it makes the best of any SPDIF signal?) - would make for a nice Squeeze box substitute but with video output as well. Now that MPD is available for it, the interface for audio is no longer an issue.

How difficult would it be to tap into these I2S lines - any pads exposed?

 

[rossl]

I have the older A-100 popcorn hour, it appears to have some different parts. Everything is very, very small.

The HDMI chip is marked SIL9002CSU and the DAC appears to be the 10-pin chip marked 844C

I didn't take the PCB out to look for a place to solder on the underside.

 

[jkeny]

Thanks Ross,
Look like some difficulty tapping into I2S lines, unless as you said, there was something more approachable on the other side of the board.

It might be worth waiting for the next board version which is due to be announced in a week or two - said to have Gigabyte networking (which I believe is needed for HD playback over the network). Don't imagine the current box would have difficulty with multichannel 24/96 audio?

 

[adelias]

I have an Egreat EG-M34A which should be very similar to the PCH A-110.

http://i22.photobucket.com/albums/b331/Sotos67/Egreat-EG-M34A-Top.jpg
http://i22.photobucket.com/albums/b331/Sotos67/Egreat-EG-M34A-Bottom.jpg

BTW, it has no problem streaming HD video even without gigabit ethernet.

 

[jkeny]

Thanks Satgeek, for the images - looks to be very similar to PCH A110. Great to hear that it doesn't judder on HD video over ethernet. I guess waiting for new board is not needed.

How does it sound compared to your audio transport?

 

[rossl]

I see the info on the new Popcorn Hour has been updated on their web site.

The new box has multiple drive bays and it's certainly big enough to house an added Sabre DAC circuit board.

468mm x 133mm x 342mm

It would be nice to see pictures of the insides.

http://www.popcornhour.com/onlinestore/index.php?pluginoption=productspec&item_id=12

 

[jkeny]

Thanks Rossl, for the heads-up. Not much different to A110 as far as I can tell but not much more expensive either $299
- gigabyte nic
- LCD screen 192*64
- some more USB ports
- extra disk ports

I presume it uses the newer Sigma chip?

 

[rossl]

I presume it uses the newer Sigma chip?

SMP8643, 667MHz CPU with floating point coprocessor.
That is the newer, faster chip.

I found some more information and pictures here:

http://www.networkedmediatank.com/wiki/index.php/Popcorn_Hour_C-200