Aux vs. disk

I think the disk will sound better. I haven't done the test or anything, but it seems to me that the patch cable between the iPod and the jack (not to mention the connection between the jack and the stereo head) would add extra noise. Also, you'd be processing the signal through another amplifier, as well (in the iPod). On the other hand, the difference may be negligible.

 

The processing the CD as opposed to the analog signal passing through a cable would certainly have to be better.
However, how much better and whether a human could detect the difference...

 

I get a hum from iPod when (I figure) it is reading and caching the rest of the current song, right at the beginning of every new track. This (pretty minor) high-pitched whine lasts about 3 seconds into the currently playing song but after, the audio quality is pretty good. Needless to say, this never happens with CDs or MP3 CD-Rs. I have to agree with the simple logic of added noise, too, from an additional amp (in iPod) and the added wiring (iPod to AUX input, input to stereo head). Fewer inches of wire is always better.

 

When using my IPOD Nano in the car, I've never experienced any unexpected/unwanted sound (hum, hiss, etc.) with the exception of an occasional pop if I plug it in with the IPOD on and the radio already set to AUX.
I avoid the pop by plugging the IPOD in powered down.
(I use the Nano in the car without a charger.)

I imagine different model IPODs may exhibit different results.

 

the ipod nano is a "memory stick" so it has no hard drive. I'm sure the hiss is from running the hard drive to cache up new music

 

That's what I figured.
So it's not noise from/through the AUX port and cable but simply the operating noise of the hard drive of the IPOD.
I imagine that closing the IPOD inside the armrest would reduce its noise considerably.