The Apple diyMod: My Take on the Famous iMod [56k killer] Featuring 3G, 4G, 5G and nano 1G!
Jun 3, 2008 at 9:39 PM Post #1,126 of 3,220
hey guys. I have been looking into this diyMod recently. I saw that RWA does this and the headphone out is not messed with. Therefore you can still access the same bad quality sound via the headphone jack.

With the DIY mod can you still access the headphone jack or is it unuseable?
 
Jun 3, 2008 at 10:34 PM Post #1,127 of 3,220
Quote:

Originally Posted by AGC /img/forum/go_quote.gif
hey guys. I have been looking into this diyMod recently. I saw that RWA does this and the headphone out is not messed with. Therefore you can still access the same bad quality sound via the headphone jack.

With the DIY mod can you still access the headphone jack or is it unuseable?



The 5G iPod uses the Wolfson DAC "line out" for line level signals and "headphone out" for headphone signal so by doing the mod on the line out, there is no change to the headphone functionality. Kind of makes you wonder why there is so much crap in the output stage if they're simply using the WM chip for it
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Jun 3, 2008 at 11:15 PM Post #1,128 of 3,220
aha.. thats rediculous.

So does it matter what wire you use to connect the pads in the 5g ipod mod? I have 26 awg wire that I think will work. Dont have 30 awg... but it is from a cat3 cable.
 
Jun 3, 2008 at 11:42 PM Post #1,129 of 3,220
Quote:

Originally Posted by AGC /img/forum/go_quote.gif
aha.. thats rediculous.

So does it matter what wire you use to connect the pads in the 5g ipod mod? I have 26 awg wire that I think will work. Dont have 30 awg... but it is from a cat3 cable.



Whatever fits, feel free to go as "audiophile" as you wish. I used 26awg gold plated copper in Teflon and it was a very tight fit.
 
Jun 4, 2008 at 1:28 AM Post #1,132 of 3,220
AGC:

The diyMod allows you to choose whichever configuration fits your needs. If you want to use the headphone signal through the dock, if you want to use the line out signal through the headphone jack, if you want to use a cleaner line out signal through the dock, it's all up to however you want to wire things. The short answer to your question, then, is that the headphone jack can be used if you want it to be.

electronicmaji:

What FallenAngel said.
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I've had people offer me their classics for the purpose of this thread, but no one has actually sent me anything yet. I think it would be pretty straightforward figuring out how things work using the resources of the internet (which is how I figured out the diyMod for the 4G in the first place), so it's only a matter of someone doing the grunt work. This thread makes things way simpler in terms of exploring other iPods, such as the 1G, 2G, 6G, and nano 2G, so when anyone is willing and willing to share...
 
Jun 4, 2008 at 3:41 AM Post #1,133 of 3,220
Back again. The documentation of the 3G mod provided in the beginning with further clarification later in the thread shows the use of resistors to ground. However, mention is also made that these are not necessary. If I mod my 3G, I want to leave the headphone out untouched, and install the Blackgates inside, routed to the line out of the dock. The lineout will only get use hooked up to an amplifier. Do I need those resistors, or can I just go DAC ==> BlackGates ==> Dock?

Also, I just popped my iPod open (didn't have the tools, but a combination of thumbnails plus credit card did the job without any damage
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), and noticed that over the board there is some black tape covering the upper area near the headphone plug and hold switch. Does this serve any real purpose? Can I just take it out?
 
Jun 4, 2008 at 5:13 AM Post #1,134 of 3,220
You don't need the resistors. They're only useful for low impedance loads, so the high input impedance of most of the amps I've seen around here remove the need for the resistors. DAC -> BGs -> Dock works great.

The black tape serves to keep certain components in place, but I found that I was messing around inside the iPods that I removed them instead of constantly removing and replacing them. Unless I'm missing something, I don't think they're completely necessary.
 
Jun 4, 2008 at 5:30 AM Post #1,135 of 3,220
Thanks for the input!

In case you are interested, I took some macro shots of important spots while my iPod was open that I can post here. Also, I was able to trace the paths from DAC to Dock, and pinned down the 100k Ohm resistor to ground, the 100 Ohm resistor in series, and exactly the point that goes to the dock connector. I need to upload and label them, is there any interest?
 
Jun 4, 2008 at 2:20 PM Post #1,136 of 3,220
Quote:

Originally Posted by patton713MW /img/forum/go_quote.gif
Thanks for the input!

In case you are interested, I took some macro shots of important spots while my iPod was open that I can post here. Also, I was able to trace the paths from DAC to Dock, and pinned down the 100k Ohm resistor to ground, the 100 Ohm resistor in series, and exactly the point that goes to the dock connector. I need to upload and label them, is there any interest?



Please post them. I don't have a 3G myself, but there are often people who read these threads/forums but never post. I'm sure there is someone with a 3G iPod that would appreciate you taking the time to upload your macro shots.

Heck, the geek in me just wants to see them
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Jun 4, 2008 at 5:16 PM Post #1,137 of 3,220
Hi everybody.

My imod is finished. Does it work? I don't really know because I'm waiting a dock cable to connect to my Xenos headamp. The ipod runs and I still can hear the music with the headphone jack so there is no damage inside.

The story.
At first, I wanted to use a compact flash! Why? Just for fun
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Later, I discovered this very intersting thread and I wanted to do this mod. It was the opportunity to take the advantage of the CF size and use the space for the BG caps. Yes, my goal was to put the caps inside the ipod in order to have a truly portable player : no need for special cable! I bought a broken ipod and I wasted a lot of time to test the imod : opening the ipod in a safe way, desoldering components, soldering 30awg cable, etc. I used a hand lens to control the desoldering and soldering operations.
After many hours of a hard work, I decided to do the mod on my ipod. As you will see on the pictures, I used a little hole on the motherboard for the two wires from the DAC. To do this, I removed some plastic thickness of the ipod case. The caps are soldered on the other side near the CF adaptor. Of course, now the path from the DAC to the DAC is longer. I hope it will not be a problem. Wait and see.

gueri_fr

Attachment 5055

Attachment 5057

Attachment 5059

Attachment 5061

Attachment 5063




 
Jun 4, 2008 at 6:43 PM Post #1,140 of 3,220
As requested:

2550965971_71a846ee0b_o.jpg


A - From Pin 17 (ROUT) on the WM8731
B - From Pin 16 (LOUT) on the WM8731

C - To Pin 3 on Dock connector (Right Line Out)
D - To Pin 4 on Dock connector (Left Line Out)

E - Ground

F - R74 = 100k Ohm resistor
G - R76 = 100 Ohm resistor
H - R73 = 100k Ohm resistor
G - R75 = 100 Ohm resistor

So, if you follow the traces highlighted in yellow, you will see that the path is:

Code:

Code:
[left]DAC (pin 17) --- C16 --- R74 --- Ground `-- R76 --- Dock (Pin 3) DAC (pin 16) --- C13 --- R73 --- Ground `-- R75 --- Dock (Pin 4)[/left]

Hope this helps fellow 3G owners!
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