PSU change effects

[sgrossklass]

Sometimes it can be instructive to have a sound card with only average power filtering. The appended noise spectra belong to the same combo of Aureon 5.1 Sky (output, clean spectrum) and SB Live! 24-Bit (input) in my secondary comp, at 48 kHz 24 bit and virtually identical levels. One was recorded with the old Fortron FSP250-60BT(12V) (maybe 4 years old), the other one with this replaced by a brand new FSP300-60PN(PF) - I think the difference is obvious. The primary goal for the change was fan noise reduction particularly under load, which btw succeeded.
Just for fun, there's also a spectrum showing THD.

 

[breadnbutter]

Thanks a lot for taking the time to produce these very interesting graphs.

I often found claims like "with the new PSU stereo seperation was much better and the bass was more defined" hard to judge. It would really be great if more people would back up their subjective impression (which is still valuable) with some objective measurement.

Did you also notice a difference from listening alone? The noise level seems to be very low in both cases, so I wonder if the change is audible at all.