I mentioned in another thread that I would post the results from the signal quality test I performed on my Dell E6500 laptop's line/headphone output. So far, all I've managed to find is a screen grab of the overall summary, and it looks like I'll need to run the test again in order to get all the details. The test was run with the Soundcard Analyzer 2.0
program, and I think I used the M-Audio Delta 66 to do the actual measurements. I remembered that when I tested the Delta 66 looped back to itself, the results were better than the laptop. (and the overall result was "excellent"). Naturally, these results have to be taken with a grain of salt, because they are the combined response of the laptop's output and the Delta's input. I forget the sample rate I used, but it would have been at least 44.1kHz. The codec chip in the laptop is capable of 24-bit/192kHz operation. Not shown in these results is the actual signal level - I have measured it at about 1.2V RMS when unloaded, and this is a good healthy level. I have measured the output impedance at approximately 70 ohms, and the signal level will drop when headphones are used. The signal fidelity may also be reduced when loaded with headphones.
If I repeat the test I'll upload the details.
It sounds very good to me. I usually listen with headphones via a headphone amp. I need to have the mixer level in Windows set to no more than 90%, in order to prevent clipping.