Сan't revive SPDIF on a Tone Board

Hello my dear friends! Faced an unsolvable problem, can’t revive SPDIF on a tonal Board in windows environment. Connect the usb original cord and other manufacturers. I put drivers from the website of the producer, deleted them and so on. The sound Card is visible in Windows, ASIO and WASAPI visible, but the sound can only be heard with an analog connection, the digital output is dead. So should I or did I miss something in the product description? Please help, I want to watch movies in 5.1 format , and here even 2.0 is not available. :upside_down_face:

Hello, From the Specs shown here, Generic Tone board version does not support SPDIF output. Only the VIM version supports SPDIF out as it passes SPDIF out from the VIMs’ GPIO.
SPDIF input is supported on both version.


Thank you very much, kind man! Another small question is whether I understood from the specification that SPDIF signal is transmitted only through 40 pin bus? With USB this signal will not receive the output?

Assuming you mean the TB’s SPDIF output, that signal is generated on the VIMs SBCs and passed thru via VIMs’ and TB’s mating GPIO connectors, to the TB’s SPDIF connector.

I have not tried feeding the TB’s SPDIF input connector with an SPDIF signal when powering over USB-C, so not sure on this feature.


Focus point of attention to the question, has anyone managed to get sound to the external DAC from SPDIF output, when connected to the computer via USB? If there are such, respond please! I’m waiting to pre-order my edge-v, I will continue to conduct research. :eyeglasses:

Unfortunately, I was unable to get a digital audio signal from the SPDIF output to TB. Tried on LE, linux & android. I want to ask the developers once again, is there such an opportunity or not? The specification States that TB has input and output SPDIF, but I can not get the result. TB was purchased to output 5.1 to a home theater receiver, not by means of hdmi.

There are two input sources for the KTB:

  • USB Input
  • SPDIF Input

Both the two input sources above will be to DAC for LINE OUT.

For VIMs users, the SPDIF can be switched to the VIMs SBC and the SPDIF output only works on VIMs SBC.

Here wanna confirm again with you that what’s the connections of your KTB? with VIMs SBC or not?

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Good day! I do not quite understand Your answer and the abbreviation “SBC VIMs”. I will try to get my wiring diagram: here have a sandwich,

until the sound get only analog RCA outputs, I want to use this sandwich as a streamer into an external DAC & 5.1 Home Theatre. If I understand you correctly, SPDIF on TB only input signal, not output? Although the specification specifies these data:

My TB VIMs edition & EDGE-V (VIM Form Factor RK3399 SBC)
Thanks, Gouwa!

SBC=Single Board Computer, the VIMs and Edge are SBCs.
Both the Edge and the VIMs have SPDIF output available on their GPIOs. Neither needs the Tone Board to output SPDIF.

Note: Only VIMs can be connected to the Tone Board by GPIO. For Edge, the Tone Board can only be connected by USB.

If the Tone Board is mounted to the VIM(as your sandwich shows), SPDIF output signal will be passed from the VIM’s GPIO through the Tone Board’s SPDIF connector.
The Tone Board itself does not produce an SPDIF signal.

For either Edge or VIM to get SPDIF output, Android Settings/Sound, it needs to be set to SPDIF.
I was unable to get this working on the VIM2, it worked on older firmware.

Edge-V’s GPIO.
SPDIF pins highlighted in yellow in this picture…

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Thank you for your support and prompt response! For starters stuck to withdraw signal through pins (13-14) from “EDGE-V” without participation Tone board, for purity experiment. The results of the experiment will write here!
It would be great if the end-to-end output of SPDIF on TB would work, without additional tricks!)

Do you meant the TOSLINK to TOSLINK showed as below:

Without a TOSLINK to COAXIAL converter as below right?


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Yes, the output source is from the VIMs SBC.

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I have checked a few things.
I have the Edge with Captain board. Using GPIO pins 13(SPDIF Sig) and 14(SPDIF GND), to my Onkyo HT-R391 I get 5.1 Dolby Digital. Works well.
I assume this will also be true on the Edge-V. Android Settings/Device Preferences/Sound/Bitstream/Audio device, set to Spdif Passthrough…

My Edge is running a Custom ATV ROM built by @mo123

The ROM is available here.

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I checked the VIM2 with SPDIF from GPIO Pins 13(SPDIF Sig) and 14(SPDIF GND), to my Onkyo HT-R391. This works, but was able to get only two channel audio. Firmware is VIM2_Nougat_V190518. Oddly, with the Tone Board mounted to the VIM2, SPDIF output did not work. I have no idea why.

User and ROM developer @superceleron has made some Custom firmwares for the VIM2. This ATV custom ROM, it is said passthrough(DTS, DTS-HD etc) works. He also offers some custom regular Android ROMS, see here.

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Thank you for your advice, but this is a very difficult decision for me, I’m trying to simplify the path of the signal. :v:

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Thank you for the work done! Indeed, the sound from the SPDIF output appeared on this build! Watched one video with sound then it disappeared for other videos and even on where he worked, I will study the problem. I am glad that the goal is achieved, and the equipment works.

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Yes, I also like to simplify the path :blush:

You connection is Coaxial or Toslink?

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My connection is Coaxial, Toslink is not a very suitable signal for me, as it has limitations in signal width and quality, although it has galvanic isolation.

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Maybe I’m allowed to jump on the thread with my question:

Im wondering if I could connect this BT unit (https://bit.ly/2PiEsPt) by using S/PDIF in on the KHADAS Tone Board?

Should be possible to attach via a cable from pin1 of the BT board to pin13 (GPIO female header) of the tone board, right?