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Old 27th May 2009, 11:38 PM   #1
Pano is offline Pano  United States
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Question Hijacking I2S _ What CDP or DVD?

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
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Old 28th May 2009, 12:07 AM   #2
ejaouen is offline ejaouen  France
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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 !
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Old 28th May 2009, 11:56 AM   #3
acid_k2 is offline acid_k2  Italy
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In almost all CD or DVD player, with a separate DAC chip, you can tap I2S signals. In oldest units that should be simplier.
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Old 28th May 2009, 01:08 PM   #4
Pano is offline Pano  United States
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Yes, easier in the older, less intergrated units.

I was hoping someone here would have tapped the I2S in a recent player. Maybe not....
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Old 28th May 2009, 01:51 PM   #5
rossl is offline rossl  United States
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The Oppo 981 has this nice connector location with labels.

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


Click the image to open in full size.
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Old 28th May 2009, 02:06 PM   #6
Pano is offline Pano  United States
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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.
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Old 29th May 2009, 12:30 AM   #7
amc184 is offline amc184  New Zealand
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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:

Quote:
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 .
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Old 29th May 2009, 11:58 AM   #8
acid_k2 is offline acid_k2  Italy
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Quote:
Originally posted by amc184


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?
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Old 29th May 2009, 12:36 PM   #9
amc184 is offline amc184  New Zealand
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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.
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Old 29th May 2009, 12:57 PM   #10
Pano is offline Pano  United States
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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.
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