OK guys, I have a fantastic new product to review but had to put it aside and re-do these measurements. On top of that, had a heck of a time getting the DS DAC to recognize the new firmware. A bunch of googling eventually led me to a page that said the SD card cannot be more than 8 Gigabytes! Who the heck keeps such small SD cards around anymore? Hunted everywhere in the house 'till I found an old camera with 8 Gig SD card. Put the image on it, plugged it in upside down as instructed (!) and it upgraded. Here is the screenshot:
And our dashboard:
SINAD went up by a 1 to 1.5 dB but I think that is run to run variation. The standing of DS DAC does not change by 1 dB improvement anyway.
It was said that noise was lowered in this release so let's measure our dynamic range:
Nope. Nothing is changed.
Intermodulation distortion which also measured noise indirectly shows identical release to Snowmass:
Oddly, one area where PS Audio DS DAC did well, jitter, got worse with noise floor rising with Windom:
Could be run to run variation but the noise floor is distinctly raised with output remaining the same.
Frequency response is identical to before so no change in timbre:
Linearity is as bad as before:
The exponential rise means noise and it too has remained the same in this test.
Multitone results are identical to before:
The transformer is distorting low frequencies and nothing upstream of that can change that.
Confirming the same in THD+N versus frequency:
Conclusions
As predicated, there is no change of substance in the two releases of the DAC firmware/FPGA image. The performance of this DAC is bound by its output stage/transformer. The upstream digital processing is likely way more transparent than this is so you can do all you want there but it won't make a difference. The weakest link principle applies here quite well.
The fact that people are reporting differences in what they hearing is simple to explain: they are testing it wrong. Short-term memory which is most accurate dissipates in a few seconds. No way can you remember fine detail after you power this down, upgrade and power it back up.
Now, PS Audio can back their claims easily.
1. They can perform a blind AB test with identical units running the two different firmware, allowing the tester to instantly switch between the two. Paul said that he could instantly hear the better sound the moment the DAC powered up with the new firmware so let's not have the tired argument of you need hours and days to discover the difference.
2. They can show us measurements that show before and after noise improvement.
Failing either, science, engineering and common sense indicates that the new firmware doesn't do anything to rescue the DS DAC from our bottom of the pile with respect to performance. It is a distortion factory and to my ears and others who have tested this DAC, is unpleasant.
If your experience is different, I suggest having a loved one change the firmware on you without you knowing a few days to see if you can tell which is which. The first person who can show this across at least 8 trials, will win $500 from me.