The Apple diyMod: My Take on the Famous iMod [56k killer] Featuring 3G, 4G, 5G and nano 1G!

[joneeboi]

I'll join in on the one-man convo.

It isn't too hard to get high-quality resistors. I remember reading that the series resistor is for protecting the DAC if the line out is "used improperly." I don't know if this includes right channel shorts to ground when pulling out headphone jacks, but since we're working with the iPod's dock, it may not be as big a problem as it seems. The resistors to ground will, for one thing, stabilize impedance but also it's also meant to be part of a high-pass filter. With the coupling caps and resistor to ground, a high-pass filter is formed. You can use Kiwames or Stackpoles, but Kiwames come in pretty large power ratings. Stackpoles come in more comfortable sizes, but aren't as high quality. Some prefer one's sound, some the other. Reading the paper again, it'd be best to include the resistors. To make things easier, throw them in the dock connector if you can't find room inside the iPod, especially if you're using Kiwames.

Summation: *sigh* Add resistors to ground after the caps. The paper cites 47K so that sound isn't so strongly affected by low impedance loads, but we probably won't be connecting our headphones straight to the DAC. *ahem powertoold* Check out f = 1/(2*pi*R*C) for details.

edit: I've revamped the original post for easier searching. Let me know what you all think.

[Ramblingman]

This is absolutely awesome guys, i just found this thread and cant get enough of it!! I will be trying this mod myself for sure, just one question... and i know it is probably a stupid one but i havent found it mentioned yet... will this mod work on the 5.5G ipod as well as the 5G ipod?

[joneeboi]

Your question is a valid one, as I have yet to see someone proclaim a diyModded 5.5G. My best guess is that it's possible since RWA did it. I can make a bunch of other assumptions, but that wouldn't be of very much use to you, would it? Open it up, let us know.

[jamess71]

As you guys know I broke the little tiny latch that holds the lcd screen cable in place. The moniter has no picture. It is a 5.5 80G video. I've come to my wits end with it.

Does anybody want it for cheap? I'm sure one of you guys can fix, especially if you have pulled off the DIYmod. I'm thinking around $100 shipped.

James

[EightTrack]

Originally Posted by joneeboi

My goodness, I think I totally misunderstood the question. You're trying to charge via the 30-pin dock connector? You're going to need some sort of voltage higher than 3.7VDC if you want to charge. Like Christine said, you could use a 5V USB supply. What I saw once on another site was some guy plugging a 9V into the FireWire V+ and GND to charge/add extra run time. For Firewire, you can leave pins in slots 19 and 20 for V+ and for pins 29 and 30 you use for GND. For USB power, use pin 23 for V+ and 15, 16 for GND. I don't know which standard charges more efficiently, but either way, I don't think your PDA battery will be able to fill the charging position. You could say it...can't...take charge...

I have plenty more battery jokes where that one came from.

yea that was it sorry im piss poor when it comes to explaining things, what Im trying to do is make this batt. work so that I can Rockbox the mini and have something that'll last a while when I bus / fly / train it from state to state to visit friends and not have to carry a bunch of **** around (chargers,cables etc...I like to travel w/ as little as possible)
and I only need minimal music for these trips and the compact mini fits perfect in my pocket w/ my knife and a few other things

but regardless of where I place the wires on the little white connector I cant get it to turn on so I was thinking I could plug it in through the bottom and it would allow me to play for however long the batt lasts. so far I have been proven wrong but havent given up yet. as you can tell im really new to all of this but we all gotta start somewhere

thanks for all your help Guys & Gal

also since you said it would take 5v to charge this is just a thought...but couldnt I just go out and buy a batt thats say 1700mah (guestimate) at 5v ? and then solder to a dock connector for back up / charging purposes ?
now I dont know if such a batt. exists or if this is just an assinine thought I'm just putting it out there

[iQEM]

Originally Posted by jamess71

As you guys know I broke the little tiny latch that holds the lcd screen cable in place. The moniter has no picture. It is a 5.5 80G video. I've come to my wits end with it.

Does anybody want it for cheap? I'm sure one of you guys can fix, especially if you have pulled off the DIYmod. I'm thinking around $100 shipped.

James

can pict and share here what it's look like (the damage latch)...thx !

[jamess71]

thanks for all the help in this matter. I gave up and sold it to cfcubed. He was the first of many interested in it.

Ordered a Cowon A3 60G. I can't wait.

Later
james

[dgbiker1]

Originally Posted by joneeboi

I'll join in on the one-man convo.

It isn't too hard to get high-quality resistors. I remember reading that the series resistor is for protecting the DAC if the line out is "used improperly." I don't know if this includes right channel shorts to ground when pulling out headphone jacks, but since we're working with the iPod's dock, it may not be as big a problem as it seems. The resistors to ground will, for one thing, stabilize impedance but also it's also meant to be part of a high-pass filter. With the coupling caps and resistor to ground, a high-pass filter is formed. You can use Kiwames or Stackpoles, but Kiwames come in pretty large power ratings. Stackpoles come in more comfortable sizes, but aren't as high quality. Some prefer one's sound, some the other. Reading the paper again, it'd be best to include the resistors. To make things easier, throw them in the dock connector if you can't find room inside the iPod, especially if you're using Kiwames.

Summation: *sigh* Add resistors to ground after the caps. The paper cites 47K so that sound isn't so strongly affected by low impedance loads, but we probably won't be connecting our headphones straight to the DAC. *ahem powertoold* Check out f = 1/(2*pi*R*C) for details.

edit: I've revamped the original post for easier searching. Let me know what you all think.

After thinking this through with reference to the Wolfson sheets, I've come to the conclusion that "improper use" is something more sinister than shorts upon headphone removal since the schematic for the headphone out don't include these resistors. Given their small size compared to the load impedance, they have a minimal effect of the filter corner frequency so I don't think that's what they're for. My guess would be to protect the DAC from accidentally plugging a source into the line-out jack (i.e. two voltage sources shorted together). It's just a guess though.
Going back to the original post on this topic, I don't think removing the "Z" things or the dock inductors will have any ill effect since they are not included in the Wolfson schematics. I doubt anything on the ipod would be hurt since we are essentially disconnecting the line-out dock pins and using them for another purpose.

[joneeboi]

I'm glad you could add your insights. Paralleling voltage sources would definitely not be a good idea, but as long as we're using dock connectors going to male output plugs, you'd have to go out of your way to destroy the DAC.

[dgbiker1]

Originally Posted by joneeboi

I'm glad you could add your insights. Paralleling voltage sources would definitely not be a good idea, but as long as we're using dock connectors going to male output plugs, you'd have to go out of your way to destroy the DAC.

Is that a challenge? *Plugging DAC into 120V outlet* Yea, I agree that it's definitely safe with the dock connector as long as you unplug the dock connector and not the male plug first.

[joneeboi]

Originally Posted by dgbiker1

Is that a challenge? *Plugging DAC into 120V outlet* Yea, I agree that it's definitely safe with the dock connector as long as you unplug the dock connector and not the male plug first.

How do you figure?

[dgbiker1]

Originally Posted by joneeboi

How do you figure?

Not being sure what gets shorted to what upon plug removal, I could see the male plug on a Dock->Male Plug interconnect shorting ground to one of the channels (can you short two bands on the plug?). It just seems safer to disconnect the dock first and prevent any kind of shorting... but then that brings me back to the fact that the Wolfson schematic for headphones doesn't include resistors so it doesn't matter? I don't really know I'd rather play it safe and disconnect the dock first, but that's just me.
BTW: I've seen a few of your threads... good stuff! Thanks for all the info.

[joneeboi]

Thanks.

Yeah, that makes sense. Disconnecting the dock connector doesn't short anything, but taking out the male mini shorts the right channel to ground. That really applies to general iPod dock use, not just to the diyMod. Good idea, though.

[joneeboi]

Discussion on diyMod digital out continues. Follow along at DIY iPod digital out.

[iQEM]

i like the last post of yours there, anyway my nu clickwheel had arrived & i had replace the old one...now my Nano back to works, have to finish the mod right away...