Is iPod Digital Output Possible?

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

Steve

what is the latest on our project? Have you completed a product that can bring digital out of the iPod to an external dac?

Thanks

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

Alpine makes a head unit for cars that does not have a CD player. It claims to take the digital output from an Ipod. So it must be possible.
Also, check out Red Wine Audio. They do upgrades on Ipods though not the latest ones. They upgrade the analog section because they claim the DAC is top notch already. One review I read said that the upgraded unit is pretty much reference quality.

Alpine makes a head unit for cars that does not have a CD player. It claims to take the digital output from an Ipod. So it must be possible.
Also, check out Red Wine Audio. They do upgrades on Ipods though not the latest ones. They upgrade the analog section because they claim the DAC is top notch already. One review I read said that the upgraded unit is pretty much reference quality.

I have the Alpine iPod interface in my van. I'm not certain it is the one you are referring to but it was the only one they offered when I purchased it - basically a separate black-box interface that connects to the dock of the ipod and feeds the signal to the head unit. It works great (very convenient and sounds OK as far as car stereo goes, but is easily bested by a CD in the same head unit). It does not claim to take digital out from the iPod. It is a $150 accessory (when I purchased it) and I assume it is just taking the line output like all the other inexpensive docking devices for iPod and amplifying the line signal. I am quite sure that the Alpine head unit that I use does not have an internal DAC, nor is the black-box interface contain a DAC itself according to the manual. That Alpine iPod interface has been around for a couple of years now if it is the same one I have. With all due respect to Vinnie and Red Wine, my experience with the Wolfsan DAC in my iPod simply judging from the line output and decent interconnects would certainly not suggest it is a top notch DAC. I have no doubt Vinnie can improve the line-output signal, but that would not improve upon the DACs abilities which are critical in what you hear at the other end. I found the iPod line output to sound 2-dimensional and lacking in dynamics in the systems I've listened to it...fine for casual listening, but sure wouldn't want to sit in front of it for long. I've read some positive words for Vinnie's iMod, but can't recall any giving it the specific praise you mention as "reference quality" digital front end. Is there a new review out recently or any changes to the iMod?

Marco