At 1 kHz, THD+N was 0.1%. That is a little high, but still acceptable. However, notice how low the noise floor is. That's because the iPod runs on a battery, and shows why some high performance preamplifiers out there also run on batteries.
Using 1 kHz and 1.5 kHz, the A+B peak at 2.5 kHz was 66 dB below the fundamentals, and the B-A peak at 500 Hz was 70 dB below. Not bad.
When the same test tones were stored as an MP3 file (192 kb/sec), the resulting spectrum was nearly identical.
At 5 kHz, THD+N was 0.23%. Again, a bit high, but acceptable.
At 5 kHz and 6 kHz, the IMD peaks were low.
At 10 kHz, THD+N was 0.04%.
With 10 kHz and 11 kHz, A+B was 68 dB below, and B-A was - 74 dB.