Originally Posted by bommai
Which firmware version. I thought I had the latest and I don’t have any hisses converting from dsd to pcm.
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It's the latest US version, M36.R.0338 which apparently only removes Gracenote.
I tried a 16- and 24-bit 176.4KHz PCM file from a flash drive (over two different AudioQuest HDMI cords swapped to test) and no hissing or alias noise. I also tried 88.2, 96, and 192 .wav and flac files, no issues. I only get high-frequency hiss (aliasing noise) when playing SACD that is internally converted to PCM. I'm 95% sure it didn't have this issue before as I would have noticed something as annoying as that, but could be wrong. I tried the CD layer - no issue with noise. I tried both HDMI outputs. I also confirmed that playing an SACD over the COAX has no issues (and yes, this is a rare player that plays SACD over COAX at a downsampled 16-bit 44.1, and NO it's not secretly playing the CD layer on a hybrid disc.)
What's interesting is that if I use the sample rate conversion function in my DAC to convert the 176.4 to 88.2, the aliasing noise is gone and it sounds much better, but still has some weirdness to it. I have not tried a .dsf or whatever DSD file from a USB stick yet, but will follow up. It's as if the 50k high pass cutoff filter isn't in place.
It's weird that Sony decided to use 176.4KHz instead of 88.2 like dozens of other players, and in the case of DSD>PCM conversion, the higher sample rate ISN'T better.
Here's an example on an Oppo:
"Why not 176.4KHz when converting SACD to PCM?
The hardware is capable of doing 176.4 and the licensing is not different. OPPO believes that 88.2KHz actually produces a better quality result for SACD DSD to PCM conversion. OPPO feels that even to offer 176.4 as an option would mislead people into thinking the higher rate must be better when that's simply not the case.
SACD players do not convert at a higher rate -- as measured at the Analog output. The process of producing Analog from DSD for SACD requires a 50KHz filter (just as exists in the OPPO's DACs when DSD-Direct-to-Analog conversion is in effect), which is the equivalent of a 100KHz sampling rate limit (see Nyquist Limit). 88.2 is the highest multiple of 44.1 that does not exceed 100."
To me, it sounds like the UBP-X800 with the latest firmware is not using that 50k filter cutoff. I have no way to confirm since I can't downgrade and don't have another player... I'll probably just keep this unit for Blu-Ray only and get a different SACD transport..