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…
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!