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Khadas Tone board and tosslink adapter

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#1
Will a tosslink adapter affect the signal of the source? My source only has optical out and the tone board only allows for s/pdif connection. Will a converter harm the source signal?

Also, will the tone board play music directly from my google pixel 2 xl that only has usb audio out?

Thanks in advance.
 
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#2
From tests I've seen, Toslink is free from issues, and does transmit bit-perfect signal on modern motherboards (though there were some issues back in the AC97 codec days).

I'll be converting my motherboard's Toslink optical to Coaxial SPDIF using the Monoprice converter I got off Amazon.

Also, I recall Amir saying that Toslink to Digital Coax SPDIF does not result in any fidelity loss, and the monoprice converter was specifically mentioned in that discussion.
 
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#3
From tests I've seen, Toslink is free from issues, and does transmit bit-perfect signal on modern motherboards (though there were some issues back in the AC97 codec days).

I'll be converting my motherboard's Toslink optical to Coaxial SPDIF using the Monoprice converter I got off Amazon.

Also, I recall Amir saying that Toslink to Digital Coax SPDIF does not result in any fidelity loss, and the monoprice converter was specifically mentioned in that discussion.
Thank you so much for responding. I appreciate it.
 

WondrousHippo

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#4
From tests I've seen, Toslink is free from issues, and does transmit bit-perfect signal on modern motherboards (though there were some issues back in the AC97 codec days).

I'll be converting my motherboard's Toslink optical to Coaxial SPDIF using the Monoprice converter I got off Amazon.

Also, I recall Amir saying that Toslink to Digital Coax SPDIF does not result in any fidelity loss, and the monoprice converter was specifically mentioned in that discussion.
Any chance you have a link to that? :)
 

gvl

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#5
Toslink and Coax are different mediums but both carry S/PDIF-encoded data. It would seem the question here is not about Toslink being inferior of the 2 but if adding a Toslink to Coax converter may degrade the sound. Good question, I remember some members here reporting certain such converters being responsible for adding gobs of jitter, so they can in theory and DAC-dependent harm the signal . That said, I don't think it would matter much with the Tone board given the ESS chip runs in async mode clocked by its own crystal and has internal jitter rejection means.

As for running from Pixel, you need to try it, you will need to use an OTG cable/adapter. Even if it runs with a direct connection it will likely drain the phone's battery pretty fast, a powered USB hub in between the phone and the board should help with the battery drain and may be the only way to go if the phone rejects the board due to the board power requirements exceeding the phone's limits. You want to use a player app that can output bit-perfect data to the audio device, I think most of not all stock players send audio through the Android audio stack which affects the signal and not in good ways.
 
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#6
Any chance you have a link to that? :)
https://www.amazon.com/gp/product/B002HWZN4W - monoprice converter I purchased. It comes with a 6v, 250ma PSU.
https://www.amazon.com/gp/product/B00FMZX5RI/ - Digital Coax cable I chose.

I use the AmazonBasic Toslink cable specifically because I saw that Zeos from Zreviews liked the springiness and construction of the cable. It's precisely that sort of thing that he's useful for cuz I also wanted a 'boingy' cable :)

https://www.audiosciencereview.com/...f-wesiontek-khadas-tone-board-dac.4823/page-3 - this is the page where Amir tests the SPDIF performance of the Toneboard, and it's slightly better than USB.

https://www.audiosciencereview.com/...f-wesiontek-khadas-tone-board-dac.4823/page-4 - And here he tests the SPDIF jitter and DNR (slight improvement). He also shows the ESS IMD hump in a graph of THD+N vs Level. I'm still quite curious about this issue, so I'm following the ongoing investigation. I suppose it would present itself during quiet samples of audio (though still inaudible)?

Now I'm hunting for the discussion about Toslink to Coax Digital conversion.

FOUND: https://www.audiosciencereview.com/...s-atom-headphone-amp.5262/page-17#post-122623 - Amir talking about Toslink to Digital Coax converter in exactly my use case, monoprice was linked.

Edit: Damn, the forum search feature really works better than I expected!
 
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#7
@Archmage thanks for all the great information. I just picked up the converter for 7.36 on Amazon. I think I have some tosslink cables and coax for the digital line. Can't wait to get this up and running.
 
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#8
Toslink and Coax are different mediums but both carry S/PDIF-encoded data. It would seem the question here is not about Toslink being inferior of the 2 but if adding a Toslink to Coax converter may degrade the sound. Good question, I remember some members here reporting certain such converters being responsible for adding gobs of jitter, so they can in theory and DAC-dependent harm the signal . That said, I don't think it would matter much with the Tone board given the ESS chip runs in async mode clocked by its own crystal and has internal jitter rejection means.

As for running from Pixel, you need to try it, you will need to use an OTG cable/adapter. Even if it runs with a direct connection it will likely drain the phone's battery pretty fast, a powered USB hub in between the phone and the board should help with the battery drain and may be the only way to go if the phone rejects the board due to the board power requirements exceeding the phone's limits. You want to use a player app that can output bit-perfect data to the audio device, I think most of not all stock players send audio through the Android audio stack which affects the signal and not in good ways.
Thanks gvl. do you have a recommendation on a powered usb hub? Anker has a simple 9 port powered hub. Will the power from the hub harm my phone? Thanks.
 

gvl

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#9
Any hub will do. Your phone will be ok, you connect it to the "uplink" side of the hub as it (the phone) is the host with the OTG cable.
 

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