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Topping E50 + Tidal + OFS MQA

ExPerfectionist

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I have a question about Tidal and Master files and how they're being read by my Topping E50.

I have Tidal Hifi+ running to a WIIM Pro, connected to a Topping E50 via coax, then out to the receiver via RCA. The E50 only does full MQA over USB so I know I'm only getting a limited version of the "master" tracks (render not full decode).

*I'm not trying to get full MQA decode/unfold (I don't have a PC/streamer with USB to hook to it) and I know it's lossy so that's not my goal. I'm not here to debate that or sound quality. I'm just trying to understand the signal path and the process of what's happening to the file, and what the WIIM + E50 are actually playing. Before I got the E50, I had the WIIM Pro hooked to my Marantz SR5015 and the readout would say 96kHz and 88.2kHz on these files, not drop to 44.1 on the 88.2 files like below.


On the E50 when a "Master" track starts it shows 88.2 etc with a "PCM" then switches to a different/same number but it shows OFS and no PCM.

Some tracks start out with "96 PCM" then go to "OFS 192" which makes sense. OFS is supposed to be ‘Original Frequency Spectrum' and indicate that the OFS number is the original track, while the PCM number that shows first is what the original file actually is.

However I'm encountering a lot of Master tracks that start off at say "88.2 PCM" then go to "OFS 44.1." Which makes me think that it's an 88.2kHz stream, but the original base file is 44.1 and MQA is somehow just doubling that to give the appearance of having a higher resolution than it is. IOW being deceptive about the quality of the file.

In the WIIM app it's still reading as 24 bits 88.2kHz. And the ones that go "96 PCM" > "OFS 192" show as 24 bits 96kHz in the WIIM app.

On the non-Master tracks, the E50 keeps "44.1 PCM" on the display.

Am I understanding this correctly, that Tidal "fakes" 88.2kHz files by doubling the 44.1kHz encodes? Or is there something else going on?
 

voodooless

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Isn’t the DAC just showing the two sample rates involved: first whatever the first MQA unfold ends up to be, then what the original sample rate is?

Looks like it:
"OFS": Confirms that the product is receiving an MQA stream or file. This delivers the final unfold of the MQA file and displays the original sample rate.
 

Snoopy

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.

Am I understanding this correctly, that Tidal "fakes" 88.2kHz files by doubling the 44.1kHz encodes? Or is there something else going on?

You can call it Upsampling or unfolding it's basically like the pcm version of what DSD did with "noise" pushed it in the inaudible range. And Mqa seems to be using a fast roll-off Filter.
There is really not much more to it.

If you enjoy it , good for you.
 

mizwdev

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I've same with WiiM Mini, but there is something changed, cause when I connect my phone with usb to E50. I also get OFS, but in the past is it was really showing me MQA, so there is something changed, phone app maybe ?
 
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