Definitely check out the Musical Fidelity X-10v3 tube output buffer to put a definitive end to this thread. Tube playback for ipod is easy, cheap & necessary. Hooked up in between your ipod and your preamp it makes ipod sound like a multi thousand dollar cd player
With all due respect to the enthusiasm of the poster trying to sell his MFX-10v3, my experience would not point to supporting his/her claims. Any playback using the iPod as a DAC is limited exactly to the DAC built into the ipod. That DAC is not bad for a tiny walkabout unit, but, no matter what you do to buffer the line output, nothing is going to make it resolve and define the music like a really fine DAC has the potential of doing. In my experience, output from the ipod lacks very clearly in the low end, and in resolving subtle detail. You can plaster anything you want between the iPod and your amplification source...if you are using the line-out on the ipod (and as far as I know you can do no other without interfacing a computer) you are limited to the old addage that holds very true in audio: Garbage in = Garbage out. You may be able to make the garbage smell sweeter, but it's still garbage IMO. Now I'm exaggerating here; I agree the iPod is a very convenient and impressive tool for toting around a good chunk of your music library, but it ain't gonna replace the DAC in my system any time soon. I'm sure that the tube buffer has the potential of making the iPod an easier listen, and for that reason I can understand the enthusiasm of Mattcecil to some degree. My tube OTL head amp definitely sounds better than listening straight out of the iPod with either set of headphones I use (iem's and big-ass cans). But my OTL amp will never put back detail nor low end resolution that isn't there in the first place. If you are getting better resolution and a more engaging presentation from an iPod with a tube buffer than you are with your high-end rig, I would strongly consider changing out your front end in your system...and NOT to an iPod for god's sake! Just my .02 cents.
Marco