MQA processing + audio output on analog RCA and SPDIF RCA


First, I’d like to say that this device is great and enjoying it, especially from line out more than headphones.
Volume control on line out would be great, and regarding headphones, I found it has a bit less power than my other headphones amp, but it’s good.

Now, I saw that there will be a new firmware that will support the SPDIF output, but I don’t understand why it should not allow to send a stream after MQA processing on this output, while it will od it one the analog RCA.
Once the MQA file is fully decoded(+rendering if any), the signal goes to the DAC to be converted from digital to analog, so it should also be able to send this signal without doing any conversion on the SPDIF output, with the exception of a MQA file with higher than 192kHz sample rate needing to be down sampled to 192kHz as it’s the maximum supported on the SPDIF output.

If that’s the case, isn’t it possible to limit the MQA processing to render up to 192kHz instead of completely not offering MQA audio (post-processing) on the SPDIF output ?

Offering this option would allow to use the Tone2 Pro as a MQA decoder+render (up to 192kHz) and send this digital signal to another DAC potentially being preferred by user, but not having MQA support.


Hi,thanks for your good suggestions.
MQA and SPDIF out can not realize together,because we use XU216-512-FB236 as processor which the resource is exhausted.So we can just realize either MQA and SPDIF out.

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Thanks for your answer.
There’s still something I don’t understand : if we can send MQA signal on the SPDIF Input (by for example using the Tidal app with “MQA passthrough” setting turned on), it’s because it doesn’t go directly to the XU216 chip, so I supposed that the SPDIF Output is also on his own, and it’s XU216 that processes it.
How is it impossible to let the XU216 do the MQA process, then send the digital signal out of it to the SPDIF Output ? Especially when it’s possible to send this digital signal to the ES9038Q2M converter

Or if the XU216 chip is still linked to the SPDIF Input and it takes load on the processor even if not used, then would it be technically possible to create a firmware that do MQA processing and SPDIF Out but without SPDIF Input usable (if we need to sacrifice on feature to get some available ressource on the XU216) ?

The other possibility, certainly simpler and without disabling the SPDIF input, would be to create a firmware with MQA renderer only + SPDIF Out (instead of MQA decoder+renderer).
It would still be very usable as a lot of app can do the decoding process (Tidal app, Roon, Audivarna, UAPP…)

Users would choose their preferred firmware based on what they need most

Hi,thanks for you good advise.I will discuss this scheme with our firmware engineer. :smiley:

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Great Eric !
You designed a device with so much potential for its size that it would be great to get possibilities to exploit all the features, even if we need to change firmware depending on the needs of everyone, and sometimes, even our own needs may change.

The last solution (in bold) would certainly free up a lot of the XU216 resources since a XU208 series chip (half processing power of a XU2016 at best) is enough to process MQA rendering.

EDIT : just thought about this again, and I don’t know if you can’t create a firmware that just activate the SPDIF Output feature when we are using Renderer only.
If the playback app send decoded MQA stream, then the XU216 of the Tone2 Pro just has to do the rendering (and not working at full resources), so it may be enough to activate the SPDIF Output, and when is doing both decoding+rendering, it would disable the SPDIF Output automatically.

Or best, the firmware can have it as option that we can select via the wheel menu :wink:
This would be perfect, having all possibilities in only one firmware !
Just some clicks and rotation and we have the features as the actual firmware (MQA decoding+rendering without SPDIF Output), and some clicks and rotation and we activate MQA Rendering only + SPDIF Output option.

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Yes,thanks for your advise!We will discuss it. :grin:

From what I understand of MQA lore, unfolds beyond the first take into consideration DAC-specific filters to achieve “temporal deblurring.” If so, digital output to a downstream DAC does make sense as there’s no way for the Tone2 Pro to know how to properly render for that DAC.

I could sort-of see this making sense if we asked the Tone2 Pro to just do the first unfold (MQA Core Decoding) and then send the 88.2/96 kHz stream out via S/PDIF for a downstream DAC to render appropriately for its filter implementation.

All of this said, the analog output of the Tone2 Pro is really, really good. I’m not sure what one would hope to achieve by digitally connecting it to a downstream DAC…at least in terms of sound quality.

Right, the analog output is really good.
Having this possibility can meanwhile help benefits of the Tone2 Pro when you have several listening systems.
You can link the Tone2 Pro to a balanced system with the analog output, link it to another amp with SPDIF digital input, or DAC with SPDIF input before the DAC send it to the amp (still with possibility to use headphones too)

Once setup is done, you have headphones and two systems ready to listen to every formats, including MQA with full decoding+rendering on both systems, or at least full on one and decoding only on the other, which is better than having no decoding at all.

Not every user have a need for that, but some can