Is iPod Digital Output Possible?

At some point, isn't the easier answer to just use the USB adapter to have the iPod act like a USB drive, rather than a player?

Great article from Stereophile. This looks like a cool new piece of hardware. Wish my 60GB Ipod Photo worked with it. Guess I need 2 new pieces of hardware.

Since a few days ago there are iPOD Docks with Digital SPDIF out, made possible by the use of the Apple Authentication Chip:

- Wadia iTransport

- DLO Homedock HD

- B&W Zeppelin (I think)

The Zeppelin won't output digital like the Wadia.

I'm skeptical about the DLO dock since it just says pure digital out.

Chris

Founder
ComputerAudiophile.com

What's the price on the DLO? I can't find a release date or retail price.

Apparently $250, available March or early spring.

There is no digital out available via the iPod's USB (or Firewire) ports on the 30-pin connector. There is an analog out at line level there, and it is much superior to the iPod's built-in headphone amplifier, so that is the output of choice for best sound quality on a bone-stock iPod.

However, you can go inside the iPod and take an I2S output from the Woflson DAC chip. This involves very good soldering skills and fine wire. You could then send the I2S out to a DAC's I2S input. Again, this probably would involve soldering skills. There is such a thing as DACs with I2S inputs, but for the most part they only use the I2S internally. Thus the mods.

If you understand USB it's fairly obvious why an iPod won't be able to connect to a DAC this way ... USB is a "dumb" interface that requires a controller chip and CPU cycles to manage the connection. The iPod and any DAC are just the "dumb" ports, so there is nothing there to do the controlling.

Firewire is somewhat different in that a Firewire controller is "smart" and does not need to be told what to do. Connect any two Firewire devices and they can talk to each other and self-manage the data stream. FW chips actually are mini-computers, with a CPU, memory, and data buses.

However the early iPods with FW I still don't believe will work, going back to the earlier point about no digital audio data available in the iPod. Whether USB or FW, the iPod is seen simply as a Hard Drive, not a Digital Audio Stream.

So what are Wadia, Cambridge Audio and other using when they are (supposedly) sending PCM from the iPod to a DAC? If what you say is correct, then they must be doing A/D. And assuming that is correct, why do they have to get a special license from Apple to do that? (From reading what others have said, Apple has to be involved somehow to get data that bypasses their DAC.)

03-06-11: Gordguide
There is no digital out available via the iPod's USB (or Firewire) ports on the 30-pin connector. There is an analog out at line level there, and it is much superior to the iPod's built-in headphone amplifier, so that is the output of choice for best sound quality on a bone-stock iPod.

Man, this thread was resurrected from the dead. I started it back when the task was not possible - As I understood it, that was because of technology or permissions that Apple was not releasing/licensing. That changed with the Wadia 170i I believe around 2007 or so(?). The Wadia unit somehow extracts a digital stream from the iPods connector dock. You can then hook the Wadia's output to a DAC and, Viola - mo betta zeros and ones! Since then, as Larry_S pointed out, others have followed (probably paying the license fee to Apple I'd bet).

However the early iPods with FW I still don't believe will work, going back to the earlier point about no digital audio data available in the iPod. Whether USB or FW, the iPod is seen simply as a Hard Drive, not a Digital Audio Stream.

I've never seen an iPod with Firewire - just connectors that hook up to the Dock below and yield a USB or FW connection. I don't see your point about the iPod being seen simply as a hard drive - with a digital stream you just need a hard drive with digital audio files on it, and a devise capable of delivering (in this case the Wadia for instance), and translating them (a DAC). What's wrong with being just a hard drive? As I understood it, the only thing keeping anyone from extracting a digital audio stream from any iPod was Apple.

Back to the same question, any dock that will extract a digital signal from the Ipod and have a USB out?

..., any dock that will extract... ?

Yes.