Building a portable iPod DAC.
Feb 23, 2013 at 12:01 AM Thread Starter Post #1 of 6

lwrs10

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Got an idea here.
 
Let me know if I am going about this the wrong way here.....my first attempt at this.
 
 
I want a portable iPod DAC. Seems there is only one made so far, and its around $700 bucks. That, my fine folks, is a bit too expensive for my taste. 
 
 
So that got me thinking on how to do it on my own. Got in my car this morning, and plugged in my iPod to my Kenwood CD player with a USB cord. Then this big lightbulb went off. I started thinking, if $100 car stereos can act as an iPod dac, then why is the only portable offering $700? I found out why. Apple "made for ipod" testing and Apple approval, which can run over 100 grand! That's why the small companies have to charge $700 for a simple product, and a big company like Kenwood can fit the tech in a cheap $100 car stereo. 
 
 
Very recently I bought a Pure i20 ipod doc. It runs off 7.5VDC, and is quite compact. It also has a DAC built into it, and it sounds quite good. So, why cant I steal the circuit out of this, and put it into a portable size case and run it off a 9 volt battery?
 
 
If these companies can offer sub $100 iPod DACs, then why cant i make one for cheaper? Tonight I took apart my Pure i20 dock, and sure enough, the circuit board sound very easily fit onto a portable DAC size case. 
 
 
 
So, anyone have any thoughts? Look back for updates as I get this device built!
 
Feb 23, 2013 at 12:12 AM Post #2 of 6
The important question is why would you want to? I'm no apple fan but the internal DAC is rather good. Where it falls on its face is the amp. More than likely (unless you're very familiar with electrical engineering) you'll end up with something that sounds worse. Just get a nice line out dock and external amp. Or go about doing a DIY imod if you really feel like hacking things up
 
Feb 23, 2013 at 10:14 PM Post #3 of 6
I think you are assuming that both the kenwood and the Purei20 actually have a DAC that is interfacing with the serial output signal of the iPod, most likely this is not what is happening, rather, I suspect, they are simply using the line out signal from the dock connector. This signal is taken from the iPods internal DAC, before the signal goes through the iPods amp stage.

To do a DAC, you would need to use the serial signal that the internal DAC uses. I don't know all the details, but I'm pretty sure its not as simple as a run of the mill DAC for a PC, else there would be plenty of them to choose from.
 
Feb 26, 2013 at 10:19 PM Post #4 of 6
Quote:
I think you are assuming that both the kenwood and the Purei20 actually have a DAC that is interfacing with the serial output signal of the iPod, most likely this is not what is happening, rather, I suspect, they are simply using the line out signal from the dock connector. This signal is taken from the iPods internal DAC, before the signal goes through the iPods amp stage.

To do a DAC, you would need to use the serial signal that the internal DAC uses. I don't know all the details, but I'm pretty sure its not as simple as a run of the mill DAC for a PC, else there would be plenty of them to choose from.

 
 
this is not the case. I plug my ipod into the Kenwood with a USB cable, which does not transmit analog at all. The Pure i20 has a 32 bit dac built into it. 
 
Sep 5, 2013 at 8:25 PM Post #5 of 6
i actually thought of this also. my pioneer uses the lightning to usb cable so it would have to be processing it within the head unit right? i had another idea using a raspberry
pi as the mediator between the iphone5 and DAC/Amp.
 

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