The Apple diyMod: My Take on the Famous iMod [56k killer] Featuring 3G, 4G, 5G and nano 1G!
Dec 9, 2012 at 3:56 PM Post #2,568 of 3,220
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Hey mate, it's not that difficult really!
Take the case off the FiiO and drill the side of the iPod back panel with the corresponding on/off & volume button holes from the casing.
Bags of room in there if you have done the CF Mod but I also took off all the connectors (mini USB & phone jacks)... then it's really slim (about 3mm)
Put the buttons in the holes, then put some hot glue (or double sided tape?) on the back pane and line the FiiO up... then stick the FiiO's battery onto the back panel as well. 
You could use the ipod battery for power but there is room so why not increase the capacity.
They use the same battery & charge voltage so I just took a couple of wires from the FiiO's mini USB pads to the USB charge pins of the iPod.
When you charge the iPod you charge the FiiO.
 
Then I just wired from the DAC to the FiiO  input pads via a couple of Elna Silmic II's...then FiiO output pads straight to the LOD pins.
 
If you've done the iMod it's pretty straight forward, you just need a dremel for the button holes.
 
Oh yes, I didn't bother with the Bass Boost switch, I just left it 'ON'.
 
I didn't take any photo's but I could open it up and take some if you want.
Pretty straight forward though once you have the three holes drilled.... except for the iMod to the LOD pins... that's fiddly but the only way IMO.
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Wow! You truly are the audio wizard! Great work mate :D
 
Dec 9, 2012 at 4:19 PM Post #2,569 of 3,220
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Could anyone give me a link with international shipping for recommended Caps used in DIYmod? Some use resistors aswell, should I?


Mouser ships internationally. I don't mean to be rude or anything, but that question sounds like you're pretty unsure. Reflowing surface mount parts is really hard, and there's a good chance you'll lift some pads.
 
Dec 11, 2012 at 2:10 AM Post #2,571 of 3,220
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I am wondering how many of you who have soldered the wires to the tiny pins at the LOD. Man I tried and it's mission impossible for me!

There's not many who give it a go... I've done plenty now but the 1st one's were a challenge to say the least.
In the early part of this thread there was one other guy who gave it a go... please don't ask me to find the post 
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Dec 23, 2012 at 3:32 AM Post #2,572 of 3,220
Well, today I got the mod done. HOLY SMOKES it's a success. First off, thanks to those who gave me advice, especially Obi Wan Ke-No-Eye-Deer, Jedi Master of the diy imod. I asked this guy a bunch of ridiculous questions about wires and caps and everything else and he gracefully answered every one. I can be especially irritating because I can't just take instructions like "solder this to that" ... I need to know WHY.
 
So anyway - Thanks a bunch. It plays, syncs, and charges.
 
I have the Tarkan adapter in there with a 64 gb CF card. I managed to fit two Elna 4.7uf FILM caps in there, and wired directly to the line out pins. This is squeezed into a 30 gig back....but it's not quite perfect...
 
Those are some big caps, and my initial "dry fitting" they fit and the iPod closed up fine. BUT in real life I guess things are a bit different on the final assembly and the end of the back case where the caps are is juuuust a bit shy of closing all the way. You kind of have to squeeze the case just a bit to get the dock connector on so it's going back to the drawing board for either a little tweaking of the cap position/ wire leads or a deep, 80 gig back and larger capacity battery. Heck, maybe then I can fit the 10uf film caps in there with the deep back muu whuaah ha ha! 
 
Here's a pic, I know the wiring isn't too tidy, but as I mentioned it's coming apart again soon so that will be addressed later. Also sorry not the best pics.
 
 

 

 
 
 
So I am going to share a pointer to help anyone trying the direct to dock pins method - Have a dead iPod or iPod dock available to "harvest" some extra pins from the female dock. The pins are extremely frail, fussy, and easy to lose. Once separated from the board they pull right out of the dock. It really isn't that hard to remove them. The ones on the iPod you you are working on - you will want to desolder while getting an xacto blade tip behind them and they pop right off. 
 
Any "spares" you get from a donor you can just use that xacto knife blade to wildly cut them off the board then pull them from the dock with small tweezers. 
 
You will want to solder your wires to the pins while they are removed from the dock. If you look at the dock, counting from the left, you are operating on pins #3 and 4. #3 is right signal, #4 is left signal.  On pin #3 you will want to solder your wire kind of on the left side of it, on pin #4 solder kind of on the right. The first time I soldered the wires centered on the pins and just the thin film of solder on each was thick enough that when the pins were back in the dock they were touching intermittently. The area here is soooo small that you want to verify individual pin isolation and continuity (as needed) with a multimeter.
 
When the pins go back into the dock they are all wacky and fussy as well so you want to make sure they are seated properly in their grooves on the other side of the dock and hit them with a dab of hot glue to secure them. 
 
Well, how is the sound? I have just listened the time it took me to post this so I don't have any great comparisons, but it certainly sounds different. Going through my Leckerton UHA-6S MKII / 8610 it's quite good. My best IEM's (Heir 4.Ai) Are all out of service because I am selling them, boxed up ...Ah, I can't wait for my customs to arrive. What was I saying?
 
Back on track - but I am using the 3.Ai and I can say the sound is very good. Overall, less murky and dark then the stock iPod sound. Treble is better presented. Bass seems about the same. Just more vivid presentation of everything.
 
Dec 23, 2012 at 4:05 AM Post #2,573 of 3,220
Job well done and Congrats thegrobe.
 
I do have a practice board unfortunately the pins at the lod are cast together with plastic and non removable. So I guess I have to practice on the real one when I get all the parts and tools. Yeah Lee is very helpful and kind to answer all my questions on this. Without his help, I am doomed to fail on those pins. I am not sure if I will get the job done, but at least I have a chance with Lee's help. I will be working on a 60gb model so there should be enough room for the caps.
 
Thanks for sharing your experience and enjoy your diymod.
 
Dec 25, 2012 at 1:58 AM Post #2,574 of 3,220
Great job bro!!! Merry Christmas to you guys!
 
Dec 29, 2012 at 6:55 AM Post #2,575 of 3,220
Has anyone a jERiCOh's simple Excel corner frequency calculator, that is mentioned on the old first page?
 
A one question about capacitors voltage. Capacitance i calculate, but which capacitor voltage can I use in imod? On what depends?
Thanks
 
Dec 29, 2012 at 12:46 PM Post #2,577 of 3,220
Has anyone a jERiCOh's simple Excel corner frequency calculator, that is mentioned on the old first page?

A one question about capacitors voltage. Capacitance i calculate, but which capacitor voltage can I use in imod? On what depends?
Thanks

I am also very curious about what different uf ratings of the capacitors make to the sound. I realize that you should match this with the input impedance of the amp....but..

in layman's terms, if using the same amp, no other variables, what audible difference will there be using a 4.7uf cap vs. a 47uf cap? does the higher # (47) raise or lower the 3db point? sorry, I am not good at math.

does the different value greatly affect bass response, or anything else? thank you!
 
Dec 31, 2012 at 2:38 AM Post #2,578 of 3,220
The voltage for the capacitors is the VDC you want to block by the use of the capacitors. So anything above 4.2 volts ( you might get that if there is a short somewhere) is a safe value.


incorrect, it must be rated for the entire voltage ie. the DC offset + signal voltage swing


I am also very curious about what different uf ratings of the capacitors make to the sound. I realize that you should match this with the input impedance of the amp....but..
in layman's terms, if using the same amp, no other variables, what audible difference will there be using a 4.7uf cap vs. a 47uf cap? does the higher # (47) raise or lower the 3db point? sorry, I am not good at math.
does the different value greatly affect bass response, or anything else? thank you!


raising the cap to 47uf from 4.7 will lower the 3db point and the point intermodulation starts by a decade (for example 4.5Hz vs 45Hz) if driving the same input impedance, I cannot tell you what the numbers will be without the impedance. how audible it will be will depend on how low that 3db point is, whether it ends up in the audible band and whether your headphones are capable of low distortion down that low anyway.
 
Jan 1, 2013 at 10:07 AM Post #2,580 of 3,220
qusp said:
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raising the cap to 47uf from 4.7 will lower the 3db point and the point intermodulation starts by a decade (for example 4.5Hz vs 45Hz) if driving the same input impedance, I cannot tell you what the numbers will be without the impedance. how audible it will be will depend on how low that 3db point is, whether it ends up in the audible band and whether your headphones are capable of low distortion down that low anyway.

Thanks..this is exactly the info I was looking for- that raising the cap value lowers the frequency in which bass roll-off begins.
If using TOO high a (uf) value here, is it possible to lower the point too much- enough that you then start to affect the ability of the cap to effectively block DC output voltage? (the whole reason the capacitors are used)
 

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