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Is iPod Digital Output Possible?

I've been scouring through all the ipod accessories and cannot find what I am looking for. Perhaps it does not exist. I was wondering if there is any cable or dock that will allow me to extract a digital output from my iPod video (or any iPod for that matter)? There's plenty of adapters to pull the analog out, but it seems like you always need a computer interface to get digital output. Why? Is it just a matter of software to sort out the library? More to the point; I want to connect my iPod directly to my DAC or even to my Waveterminal (requires the squareish delivery end of a USB cable) to my DAC...is this possible? Has this been discussed previously? If so, where the heck was I? No, don't answer that last part! The authorities may be listening in! Just tell me how to get a digital stream out of my iPod if it's possible.

Marco
jax2

Showing 4 responses by audioengr

audioengr
3,282 posts
 
The iPod could probably be modded to bring-out a digital interface. I2S is probably available in there, but not S/PDIF, so a chip would have to be added to get S/PDIF. If it is too tight, the chip may not fit.

Steve N.
Empirical Audio
Manufacturer/modder
audioengr
3,282 posts
 
The Escient does not talk about modifying the iPod. This is required to bring-out a digital signal.

The only ones doing this to my knowledge are myself and MSB.

Steve N.
Empirical Audio
audioengr
3,282 posts
 
Bwhite - The digital iPod docking station is called the iRod, for Hot-rodded iPod. It will essentially replace all of the analog circuits in the iPod with external circuits of my own design. I will bring-out the I2S interface on the docking connector. The connector will dock with my own portable box, which will have rechargable batteries, D/A, headphone amp and analog volume control (Alps). It will use the AD1853 D/A converter and be non-upsampling. I may also try to drive a low-jitter master clock back up to the iPod, locating it at the D/A chip. I am considering putting line-outs on it as well, but it may not have the space.

Steve N.
Empirical Audio
audioengr
3,282 posts
 
Johnmhuntbch - I took an iPod Video apart and mapped-out the signals. The problem in this particular unit is that the signals necessary for I2S are not present. The D/A chip is run from a 12MHz clock. It is a proprietary chip from Wolfsen, cannot find a datasheet. It also uses a half-speed bit-clock. With some effort and logic, I could generate S/PDIF from this externally, but it would be jittery.

The whole point of this was to get a low-jitter I2S out of the thing. Looks like maybe a different iPod is needed. The new ones evidently use the WM8741. This I have the data sheet for. This probably has I2S going in. Not sure which iPod to buy though. This is getting expensive. I managed to put the video iPod back together and I'm giving it to my wife for use when walking the dog...

Higher priority is getting my new Formula One DAC to market right now.

Steve N.
Empirical Audio
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