Audiophile Play with an iPad as a Digital Audio Source

Photo Credit: John Grandberg

iPad as a Digital Audio Source
The Camera Connection Kit is a great method for extracting a USB digital signal on the cheap. But it won't be ideal for everyone. Those wanting to take the next step in iPad-as-transport functionality can move up to a dedicated digital dock. The concept is the same: tap into the digital signal before it gets routed through Apple's consumer-grade DAC section, and output the audio as a S/PDIF digital signal. This of course would allow the iPad to easily integrate into a high-end audio system.

The first wave of devices from Wadia and then Onkyo were strictly for use with then-current iPod/iPhone models (the iPad had not yet been released), and were fairly expensive. By now there are a few good choices that do work with iPad, and more importantly the prices have come down to a reasonable level.

But why would anyone spend extra when the CCK can do the same job? The way I see it, there are three distinct benefits of using a dock over the CCK.

  • Connection type. Though USB DACs are a very hot market right now, there are still plenty of models in use that don't offer a USB input. And many DACs that do feature USB still use compromised solutions with inferior jitter performance that won't accept a hi-res signal. A digital dock will get you an SPDIF signal that any DAC should be able to work with, and most should handle at least 24/96.
  • Power. The CCK takes up the only port on the iPad so it doesn't allow for charging. Docks will charge the unit during use, and double as a convenient place to store it during the night. No more fumbling with Apple's wall wart charger.
  • Placement. When used in a system, you probably want the iPad standing up at an angle where it is visible. The CCK requires some other method or propping up the device (I use the stock Ipad 2 Smart Cover). A dock will accomplish this without requiring any extras, and frankly it just looks better that way.

The Pure Audio i-20 is the bargain champ in this category, selling for just $99. It will give you a digital output using a coaxial or optical connection, and even has a built in DAC with analog outputs to use in a pinch. It isn't the most stable thing in the world due to the small base, however.

The other option I see used frequently is the Cambridge Audio iD100. It costs $200 more than the Pure model, but adds features such as an AES/EBU XLR output and a USB pass-through for iTunes sync. It also appears more stable.

As pictured, I'm using the Pure i-20 in a setup with a Violectric V800 DAC, Violectric V200 amp, and Audio Technica W1000x headphones. The iPad/Pure combo does not seem out of place even in a somewhat expensive system like this, and I don't feel that it is a limiting factor whatsoever.

deckeda's picture

It's hard not to look at the iPad as a bigger, better alternative to the Logitech Squeezebox when used as a streamer from iTunes.

Vsdeede's picture

A great exchange of information.

n_maher's picture

Another great article, Tyll. Regarding the price vs. performance of the iPad in the various roles that it can play as an audio device - with the ever falling prices of 1G iPad (which still function quite well, especially if audio is the question) I think that there's the real potential for something here. Recently the 1G 64GB iPad was selling for under $500, albeit a refurb model but still, that's a pretty reasonable amount of storage at that price and the 32 and 16GB versions are getting even cheaper on the used market (~$300 for the 16GB).

I also hope that someone on the Android side of the fence is listening. Some of those devices, courtesy of the MicroSD slot have even more practical potential as a music/media content provider.

Tyll Hertsens's picture
Well, cudos for this one go to John Grandberg. Thanks John.

It's funny how that Android/Apple divide works. I like my HTC Incredible as a phone much better than my iPhone, but I like the iPhone better as a media control/play device.

John Grandberg's picture

And in many ways I find Android to be superior to iOS. BUT - the lack of standards makes it tough for accessories. Now that micro-USB has pretty much become the norm, there could theoretically be a lot more things like speaker docks released. But there probably won't be for whatever reason.

I'm also disappointed that Android hasn't done more to encourage digital audio output. It seems like a no-brainer, and we wouldn't even need to buy a CCK type adapter.

n_maher's picture

Well color me stupid, nicely written piece John! I agree with your take on Android as well. I have high hopes for the next version of the OS.

droilfade's picture

I like android better. The Open Sourceness of the platform makes it much more flexible and more adaptable as well.. Some phones like the galaxy S (i9000-which I owned) have a wolfson DAC which makes listening to music such a pleasure. Then there are these awesome options for music players like the PowerAmp and let's not forget the wide range of custom ROMs which can make the whole experience much better. Cyanogenmod has a built-in DSP manager app which makes it worth while to purchase any device that those guys support :)

John Grandberg's picture

I love Android from an ideological point of view. My phone is an LG Optimus and I also use a rooted Nook Color running Phiremod MIUI v2.

However - I do wish all that "Open Source-ness" would translate more to the realm of audio. There are so many things that I can do with my iPad, which simply can't be done on my Android devices:

*I can't get USB output to an external DAC, even though it should be easy enough to do. I kept hearing that Honeycomb would allow this, but it doesn't. Now the word is that Ice Cream Sandwich will do it. We'll see.

*There aren't any docks like the Pure i-20 to allow an SPDIF output. This again should be simple enough, but since Android devices all have different physical sizes and USB port locations, it gets complicated.

*There are only a handful of speaker docks that support Android devices. This is one area where I see some improvement over the past few months, but there is still a long way to go.

As I covered in the article, the iPad has all these areas covered. If I could merge my iPad functionality and accessories with the Android UI flexibility and apps, it would make the perfect device.

droilfade's picture

+1! Agreed, agreed and agreed :)

Again, I think Android is in its nascent stages and the ICS is the first polished version of Android IMO, where a lot of thought has been given to the layout, design and features. I hope it only gets better from here and a year from now you can do all those things on your LG optimus or the Nook color. :D

gmf001's picture

newby here - great site and article btw. One question comes to mind reading thru this section. Is it possible to use HomeSharing and AirPlay to stream 24/96 to the iPad and have this HQ signal pass thru the digital outputs on the Pure i20? I'm currently wrestling with a number of options to deliver digital content to a new system. I expect I'll use an AirPort Express for my standard CD quality files using the optical out into the integrated DAC in my NAD amp. But I'm looking at options to get a small, but growing number of 24/96 audio files streamed from my main iTunes db in another part of the house to this new system.
Will the i20 do this for me. Any other ideas?

deckeda's picture

The short answer is yes, the i20 will do it for you.

You're confusing Apple's Home Sharing and AirPlay methods of moving music around. In the context of the situation here, AirPlay doesn't apply.

Your iPad can access your iTunes library wirelessly and without syncing anything. In fact, in the scenario described in the article, you could have ZERO songs stored on the iPad, because you wouldn't have to play them from there.

You would have Home Sharing setup on it (in iOS 5, look in Settings > Music for the Home Sharing part) and in iTunes, and then your iTunes library will be available for playback as "Shared" on the iPad.

Put the iPad in the i20, and now you have a pure (sorry for the pun) digital out --- the iPad will stream from your iTunes library hi res files, too. In other words the iPad will stream over files it wouldn't even be able to store internally. Hi res FLAC downloads can be converted to AIFF or Apple Lossless for insertion into iTunes with 3rd party software.

For what the AirPort Express costs you could pick up a second i20 and use it for the NAD, too, since the i20 includes a 24/192 DAC --- but then you'd possibly need a second iDevice to pick up the iTunes library.

A decommissioned iPhone or iPod touch running iOS 4.something (Home Sharing compatible) would suffice. And if streaming is unnecessary and all you want to do is playback what's stored on the iPod or iPhone, most any will do. Only the 1st-gen nano and pre "Classic" iPods won't deliver a digital output.

For more on this idea see also: << It discusses how to use almost any powered DAC with an iPad if you get Apple's $29 Camera Connection Kit, which provides unfettered digital out via USB. Just don't use it with an amp's USB "iPod" input; those are typically limited to 48kHz.

gmf001's picture

Decked & John
Thanks for your comments and clarification. I finally got a chance to get things hooked up and connected last night and was able to test both AirPlay thru an airport express optical out and home sharing using a CCK on the iPad. Both worked flawlessly across my somewhat complex home network - gigabit Ethernet backbone with a multi-AP Aruba WLAN. I've got 2 airport express APs connected via Ethernet on a hidden network to provide digital outs to the two amps in my house. At some point I'll determine if adding the i20 makes sense to provide power and a more permanent dock for an iDevice for the new NAD based system. I may devote my 1st gen touch to this.
Btw, the MDC integrated DAC (for the NAD 375 and 356) supports up to 24/192 files so no problems with the files I have.


John Grandberg's picture
Sorry, I didn't notice your question until now. Deckeda beat me to the punch with a well-explained answer though. The only thing I can add is that you need to ensure your NAD digital input can handle hi-res signals (which it most likely can but I'm just eliminating all potential issues).
Tyll Hertsens's picture
Wow! Great help for the readers here, thanks guys!
SchaqFu's picture

This is a fabulous post and discussion! Thanks!

Instead of using iTunes Home Sharing, would it be possible to stream hi res (96KHz / 24bit) ALAC / AIFF / FLAC files from an external WiFi hard drive to the iPad or iPhone 4S before outputting to an external DAC via the CCK? My goal is to stream 200+ GB of ALAC files to my external DAC (Benchmark DAC1-USB) via an iPad or iPhone without the need for (1) a separate computer or (2) an existing WiFi network.

For example, the following would be a really amazing, self-contained hifi setup:

96/24 ALAC music files --> 500GB SeaGate GoFlex Satellite WiFi HDD --> iPad/iPhone --> Apple Camera Connection Kit --> DAC1-USB external DAC --> amplifier, etc.

Has anyone done this, or know whether it can be done? Or something substantially similar that would obviate the need for a computer and WiFi network? Again, many thanks!

John Grandberg's picture

First off, great idea! I had not seen those GoFlex units before - very cool.

Will it work? Maybe. I think it really hinges on the software that Seagate makes you use for accessing your files. Without using it myself, I'm almost positive that your setup would work using regular 16/48 files. But I can't find a list of supported formats, so I can't be 100% certain it will handle ALAC. Hi-res support may or may not be there.

Or maybe I'm wrong about the requirements - will it work with other UPnP/DLNA playback software? If so, I know FLAC Player would work, except of course for the ALAC format. The Golden Ear app should work, at least in theory, as should several of the others I mentioned in the article.

One last thing - only the iPad can output 24/96. All iPod models (even the 4S) will play the file but downconvert to 48kHz. That may change at some point soon, but that's my understanding at the moment.

deckeda's picture

"only the iPad can output 24/96. All iPod models (even the 4S) will play the file but downconvert to 48kHz."

John, I wasn't aware of this. Are we still talking about streaming hi rez Home Sharing? I was under the impression an iPad would pass even more, say 24/192, and that modern iPhones and iPod touches could, too?

Trouble is, I don't know if anyone's tried it and published their findings. For cost reasons I'm drawn to the PURE i20, but even for only $100 I'd want to know if my iPhone 4 can stream hi rez and not just my iPad.

I like the idea of not needing a dedicated controller, that I can pick up whichever Apple handset is around and I have full access to my stereo.

My second question is, can you browse music while it's in your hand (i.e. not sitting in the dock) hit Play, and then set it in the dock (or connect up the CCK) and have it automagically begin playing through it to the DAC ... ?

SchaqFu's picture

Thanks, John. I guess my question then is, what external storage device is most likely (or proven) to work in the above scenario? Better yet, might it even be possible to stream hi res files from some Internet service directly to the iPad, rather than from a locally connected storage device? Thanks.

John Grandberg's picture

The second point in your original post had to do with the lack of an existing wifi network. As far as I know, NAS drives will require either direct ethernet connection or else wifi. So there really isn't much you can do, unless the Seagate GoFlex will work.

There are no direct streaming services that I'm aware of. You could always store your music somewhere like Skydrive and then download it when needed, but it wouldn't be instant streaming....

Seems like you are pushing the envelope as far as what you'd like to accomplish with your iPad. I don't think it is unreasonable though, and hopefully we can find a way to make it happen soon enough.

Jokerman21's picture

I've connected my iPad via CCK to a Musical Fidelity X-CAN v8p and it works a treat!

Thanks for the article.

deckeda's picture

What you're describing, a server/player relationship that doesn't require an existing LAN is something akin to the stand-alone solutions such as Olive or Sooloos on the expensive end, and at the moment I'm drawing a blank on the cheaper end.

What I'd expect on the lower end would be some half-assed UPnP/DLNA dependency of the sort we currently see on many network players designed for "anything:" it works within a very narrow scope and with some hinkiness.

In between is Apple's Home Sharing thing, but like UPnP/DLNA requires an existing network.

As computer nerds who love music, we are often guilty of overlooking the usability of our setups. When I think of the simplicity of inserting a CD and hitting the player's Play button (after only having to select its direct, dedicated input) I cringe at how far we've come but how much we've given up. And so I think that much of what we strive for today is to get back to that simplicity.

The broader issue in my view is how to maintain the library. Any self-contained solution must either additionally offer elegant functionality for other sources AND handle its own affairs, or have available an "inject point" where a computer's working library or other source can be accessed to build and maintain the "self-contained" library.

But there's a way out of this, even if it's just a bridge to a simpler future, and that's a dedicated computer always left on or one that can boot up in less than 60 seconds. The computer is either the player too, or just the server for an iPad or other interface. In the end it's not so *fundamentally* different than leaving a NAS on all the time.

Tyll Hertsens's picture
Thanks for your comments. I've got an old hag of a computer I slapped a big hard drive in and turned into a server with Vortex box. Serves well to address your comments. Simple as dirt ... well, almost.

SchaqFu's picture

I agree wholeheartedly with what you said. And I concur that having a dedicated computer connected directly to the external DAC is a simple, dependable solution.

But it seems to me that the technologies to accomplish what I describe--a WiFi hard drive feeding hi-res audio files to an iPad or iPhone connected to an external DAC all without being tethered to a separate WiFi network--are relatively simple and available if only someone would do a simple bit of engineering (though admittedly well beyond my abilities) and put them all together. For example, if the folks at can write firmware for the GoFlex Satellite WiFi hard drive that allows that device to serve SSH, SFTP, WebDAV and SMB services all broadcast over Bonjour on its own self-contained WiFi network, then it seems like it should be possible to turn that device or something similar into an iTunes server that supports 24/96 streaming via iTunes Home Sharing. Or, alternatively using one of the other protocols (DLNA/UPnP, WebDAV, SMB, FTP, etc.) it should be possible to create or update iOS apps that can play hi-res files (like FLAC Player or Golden Ear) to access the full contents of the WiFi hard drive via those protocols in a seamless way that makes the whole experience simple for the end user.

I guess I'm just excited about the prospect of using simple off-the-shelf hardware and software to create a truly world-class digital audiophile rig out of nothing more than an iPhone or iPad and a sub-$200 external WiFi hard drive (to be connected, of course, to external DACs, amps and headphones or speakers that may not be so low-brow).

It seems so attainable with today's widely-available technologies that I'm just surprised no one seems to have created a workable solution to date (I would love for someone to correct me about that). Looking slightly further into the future, it would be great to eliminate the hard drive as well and have the iPad pull hi-res files directly from the cloud and feed them to a connected DAC. If you're content with lossy AAC or MP3 music libraries and don't need to stream lossless (let alone 24/96 lossless) files, then the cloud solution is already possible right now via Amazon, Google and some other cloud music services. But I'd gladly add the WiFi hard drive to be able to listen to a large library of 24/96 files in that setup today.

SchaqFu's picture

John (or anyone else),

On page 3 of this article you say that a digital dock (like the Pure i-20) "will get you an SPDIF signal that any DAC should be able to work with, and most should handle at least 24/96." This is an exciting prospect, but are you aware of any conclusive evidence that the Pure i-20 actually passes bit-perfect 24/96 audio data from an iPad or iPhone to an external DAC via SPDIF? As you point out, the engineers at Benchmark Media have documented that the iPad is capable of bit-transparent output of 24/96 audio via the Camera Connection Kit over USB (, but has anyone verified that the same is true of any digital docks like the i-20 (or any others, for that matter)? And if so, has anyone determined whether these docks can pass hi-res data from the iPhone as well as the iPad? That would be huge, since the CCK doesn't work with the iPhone.

As always, thanks for the great info!

John Grandberg's picture

I've connected the Pure i-20 to my Yulong D100 DAC via coaxial SPDIF. I was able to play back 24/96 and 24/88.2, and the display on the D100 showed me the proper sample rate coming in. This DAC doesn't show bit depth, but I can't imagine why that would be reduced but not the sample rate. This is about as close to "verification" as I could get.

Everything I've read says the iPhone gets chopped down to 16/48, no matter what version of iPhone is being used. I don't exactly understand why this is so - the 4S is very similar in hardware to the iPad2. Then again the iPhone has Siri and iPad still doesn't, so clearly some differences exist somewhere.

deckeda's picture

... but the CCK is supposed to work with the iPhone 4 and 4S, at least for its intended function of connecting a camera or SD card for injecting jpegs into the Photo app. I've not read that it shouldn't work for digital audio, but perhaps you have a source?

jimmyjames's picture

Griffin has the BEACON for $70 that was introduced at CES this year. There's one for iOS and Android devices.

deckeda's picture

Seems you need an iPad 2 to play in this game.

Wish I'd done more research before buying the i20. Anything more than 48kHz gets shot down to 48 through my ORIGINAL iPad.

John Grandberg's picture
I only have an iPad2, and didn't think there would be differences like that between the generations. That's disappointing.