At this stage, I still believe the best way to determine wether you have or not a small clock unit is to be able to A/B with 44.1khz material your Hiface unit with another HiFace that you know for sure has a large clock. Differences will show up immediately if any because they are very noticeable. But of course, very few will have the opportunity to test that.
That is why an alternative method is the use of the SoX resampler in Foobar, said to be one of the best resampler available out there. That is what I have done earlier, following Xdanny suggestion, and I find it a very valid method.
Just chose some 44.1 material to play, and listen A. Then, load the resampler SoX in Foobar DSP panel to resample at 48 and listen B. Repeat as much as you want. Oh BTW, the Lavry allows to display the incoming sample rate, and I have been able to check that the resampler was indeed at work when selected. If A sounds better than B (and it does, even though someone said that the SoX resampler was absolutely transparent, it is not to my ears and in my system), you have a large clock. But if B sounds better than A (and it does as well), then you obviously have a small clock at 44.1khz.
I have done this experiment with both unit of the HiFace in my possession, the small clock unit and the large clock unit. I choosed Diana Krall, The Look Of Love, S'wonderful, for I find it a good recordings technically speaking with Diana Krall's voice very easy to isolate, and an accompanying orchestra.
With the small clock unit, the resampled version at 48khz sounds better, with Diana Krall's voice fuller and richer, with more weight and better articulation. You will also notice that the violins are more realistic sounding, with better pace and with details and intonations that you simply miss at 44.1khz.
With the large clock unit, the resampled version at 48khz sounds worst than at 44.1khz by a fair margin. Diana Krall's voice sounds thinner, more aggressive, lacking emotion. Violins in the background will make you feel unconfortable, as they stop abruptely, unnnaturally, lacking decay.
I shall say that with both units, the resampled version at 48khz sounded identical to my ears. So it really goes like this:
large clock 44.1 > large & small clock resampled SoX 48 > small clock 44.1
EDIT 08/31/2010: users reports
Users so far who have reported relevant differences either in A/B two different units, or through the SoX resampler tests:
Regal, Shamu144, Picodeloro, USG
Edited by shamu144 - 8/31/10 at 7:43am