How to imod a 4th Gen iPod photo

In this post I talked about the audio quality of the various iPods, and mentioned a mod for 4th and 5th Generation iPods that gives them excellent audio quality rivalling that of a $1500 CD player. Well, here is how to do the mod on a 4th gen color iPod photo – Apple model number A1099.

The 4th Gen iPods have a Wolfson WM8975 audio chip in them.

The pinout is something like this (this is a pinout of the WM8971).

ROUT1 and LOUT1 go to the headphone connector, via some capacitors etc, while ROUT2 and LOUT2 go to the dock connector (line out). There are resistors, capacitors and inductors of low quality on the signal path, but the Wolfson IC itself is a top of the range audio chip. The mod involves running a wire directly from LOUT2 and ROUT2, via some Black Gate capacitors, to the headphone jack, which will now become a high quality  line out. You could run it out the dock connector instead but I decided to go out the headphone jack – it loooked easier!

You’ll need a 4th gen ipod photo and a pair of Black Gate NX Hi-Q 6.3V 22uF or 47uF capacitors – they are rare and expensive. You can find them occasionally on ebay. They are no longer made but suppliers sell them off in pairs from time to time. My pair of 47uF caps cost me $16 pounds and I had to import them from the UK! Here’s a list of alternative caps you could try.

This is the ipod photo 4th Gen, it’s the color version of the 4th Gen ipod. Specs here:

Here’s my ipod open and Black Gates ready to go…

Step 1. Solder and heat shrink some small leads onto the black gate capacitors…

Step 1. Solder leads onto the black gate capacitors. I used wire wrap wire – strong but thin.
These are the resistors we will remove – they are tiny – about 1/4 the size of a grain of sugar. (This picture is magnified)
Step 2. Remove the output resistors from the wolfson DAC
Step 3 – Solder one wire from each capacitor to the output of the DAC chip. (Click on image to enlarge)
Step 4. The other wire from the capacitor needs to be soldered to the headphone jack. The inductors closest to the headphone jack are removed.
Step 5 – shove it all back in and try not to break the wires! I had to remove the plastic sleeve around the dock connector to fit the capacitors in. The capacitors sit each side of the dock connector (bottom left).

Some tips:

I used a headphone lead to hold the socket while I soldered.
I used a 500W floodlight to help me see – the soldering is fine.
Actual size of resistors! I wouldn't attempt this mod unless you have had Surface Mount experience before…


This forum is a ripper – no step by step guide on the  4th gen ipod photo though!

This site has a summary of all imods.

Red wine do a mod for $250. It’s not that expensive considering the risk involved and fine soldering needed!

Mod finished – took about 1hr work plus 2hr research plus 1hr to write it up!

Bedtime and I’ll do some tests tomorrow!


12 responses to “How to imod a 4th Gen iPod photo”

  1. paul

    I’m interested to hear how perceptible the change in audio quality is.

    can u include a pic of the unit. im not sure which mine is – it’s a iPod video. is that a 5G?

  2. I can’t hear the difference. I can hear the difference between the 4th gen ipod and the other ipods, but I can’t hear the difference with the imod! Maybe I’ve hit the limitation of my home stereo? Maybe my ears are nearly 40 years old? Jill (my wife) can pick a difference – she picked the modded one as sounding ‘more resonant’ for classical music. Bit depressing I couldn’t hear it! The songs she listened to were encoded lossless though. Just loading some of my favourite CDs with lossless compression to see if that makes a difference.

    You can check your ipod model here:

  3. Nope still can’t pick any difference.

  4. Al Bain

    Can I ask a general question about ipods?

    I want to buy an ipod with a big capacity so I can put all my music collection on it. It doesn’t need to be small and good looking. I’m not.

    But since our CD player packed it in a year or so ago I’ve been using my 2nd gen 2 gig ipod which, considering that I’ve got 35 gig of music on the hard drive, is frustratingly small.

    So, what do you recommend I buy and where should I be trying to buy it from. Would a reconditioned one be the go?

    1. These guys sell real nice refurbished 5.5th gen ipod 80G for $140 including postage.
      I just bought one last year and it’s our main ipod to listen to through our stereo and in the car, then I use a little nano for running.
      The 5.5th gen is the best ipod for sound quality, plus 80G holds your entire music library, plus $140 is cheap enough that if it blows up you just buy a new one.
      You could keep an eye on ebay for a cheaper one and get it for under $100 if you had time but these come all plastic wrapped and look almost new.

  5. Al Bain

    Bought it. It’s exactly what I wanted. And way cheaper than I thought.

    Thanks for your help.

  6. MikeC

    Thanks for the time taken to show this. I’ve been tempted to send to Red Wine. I have solid soldering skills, but I see you’ve advised you noticed little difference in sound quality, correct?

    I have the 5th Gen IPod (considered the best one with SQ) and am thinking I should just let it be.

    What’s your opinion after these years have passed?


  7. Mark

    Thanks for the post. Just a few notes for those attempting this mod:
    1. The wires from the headphones are small and work great.
    2. Use Kapton tape for protecting the wires.
    3. Elna SILMIC II caps are good replacements for the Black Gates.
    4. Using a CF card and adapter in the 5G give you extra room inside for the caps.
    5. The caps will need to “burn in” for about 200 hours to get the best sound.


  8. koko

    Can this mod be done on ipod nano 2nd gen, its with same audio chip?
    what about modding 3rd nano ?

  9. John

    Hi Wayne, how would I remove the resistors and the inductors? Sorry, I am a soldering neophyte and thought this would be a nice little diversion. Thanks!

  10. Dan

    Redwine moded 4th Gen Photo iPod model A1099

    Is there a larger capacity hard drive than the 60 GB that can be installed????

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