• Registered: 2019-12-07
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Topic: Hiby R6 III DAP coax to ADI-2 DAC FS problem

Hello,

is there a way to debug why source device coax output is not detected by ADI-2 DAC FS (v1)?

I have Hiby R6 III DAP which I wish to use as a digital transport to ADI-2 DAC FS. I purchased Hiby USB-C to RCA coax cable and unfortunately anything > 48 kHz is not detected by ADI-2 DAC FS (tested with 88.2 kHz, 96 kHz and 2.8 MHz DSD).

The same combination (except DSD which is not supported) works with Schiit Bifrost DAC which I had laying around after purchasing ADI-2 DAC FS.

Hiby support says that there is probably "electric signal level mismatch" between devices as R6 III outputs at 1 V (I doubt this is the case because 44.1 kHz and 48 kHz works and ADI-2 DAC FS specification says < 0.3 Vpp is OK if I understood this correctly).

I suspect a Hiby FW bug but because they do not have ADI-2 DAC FS available I do not think this will be fixed ever by Hiby unless I can provide some hard data to them.

But there is of course also a possibility that ADI-2 DAC FS has a bug. Maybe Schiit has different coax implementation which is not so picky and accepts a signal that is not perfect or follow a standard precisely.

  • KaiS
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Re: Hiby R6 III DAP coax to ADI-2 DAC FS problem

SPDIF Coax digital audio follows a decades long established standard.
The receiver chip inside ADI-2 is one of the most used, quasi industry standard one, exist.

If ADI-2 is not broken (check with another source) the problem lies in the Hiby.

KaiS's Website

3 Reply by Tarking (edited by Tarking 2024-01-08 11:43:58)

  • Registered: 2019-12-07
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Re: Hiby R6 III DAP coax to ADI-2 DAC FS problem

I understand what you are saying. That is why I am asking help from experts in the field to find a way to debug what is wrong with the Hiby coax output because they do not want to acknowledge that problem lies in their end.

ADI-2 DAC works fine with another source (FiiO).

The price you pay apparently when one must buy a Chinese designed product.

  • Kubrak
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Re: Hiby R6 III DAP coax to ADI-2 DAC FS problem

And do you have SPDIF set correctly? Pro vs. Consumer. I do not have ADI-2, but expect it has this setting as all RME interfaces I have do have it....

5 Reply by Tarking (edited by Tarking 2024-01-08 12:11:34)

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Re: Hiby R6 III DAP coax to ADI-2 DAC FS problem

ADI-2 DAC is consumer oriented product so no such setting exists or at least I was not able to find one.

At 44.1 and 48 kHz from Hiby ADI-2 DAC shows "cons" (short for consumer) in State Overview display.

  • Registered: 2023-06-30
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Re: Hiby R6 III DAP coax to ADI-2 DAC FS problem

Kubrak wrote:

And do you have SPDIF set correctly? Pro vs. Consumer.

ADI-2 DAC/Pro SPDIF/AES input detects this flag automatically, no need to set it on the receiving side.

Fireface UCX II + ARC USB > ADI-2 Pro FS R BE > Neumann KH 750 DSP + MA 1 > KH 120 A
  • KaiS
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Re: Hiby R6 III DAP coax to ADI-2 DAC FS problem

BTW: did you check with a different cable?

Very short cables can be problematic too sometimes.

KaiS's Website

  • Registered: 2019-12-07
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Re: Hiby R6 III DAP coax to ADI-2 DAC FS problem

KaiS wrote:

BTW: did you check with a different cable?

Very short cables can be problematic too sometimes.

I cannot do that because Hiby uses a special cable i.e. from USB-C to RCA (or 3.5 mm TRS). Stupid design choice IMO because you cannot charge the device when using coax.

I will try to get Hiby to investigate this matter using another channel i.e. HeadFi forum.

It would be helpful to know what is the coax receiver chip used in ADI-2 DAC FS v1.

9 Reply by KaiS (edited by KaiS 2024-01-09 11:10:48)

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Re: Hiby R6 III DAP coax to ADI-2 DAC FS problem

Tarking wrote:
KaiS wrote:

BTW: did you check with a different cable?

Very short cables can be problematic too sometimes.

I cannot do that because Hiby uses a special cable i.e. from USB-C to RCA (or 3.5 mm TRS). Stupid design choice IMO because you cannot charge the device when using coax.

I will try to get Hiby to investigate this matter using another channel i.e. HeadFi forum.

It would be helpful to know what is the coax receiver chip used in ADI-2 DAC FS v1.

The AKM chip right above the yellow Coax connector:

https://www.audiosciencereview.com/foru … pg.162259/

https://www.audiosciencereview.com/forum/index.php?attachments/v3-jpg.162259/

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10 Reply by Tarking (edited by Tarking 2024-01-09 11:59:13)

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Re: Hiby R6 III DAP coax to ADI-2 DAC FS problem

Maybe I am blind but only AKM chip I see is AK4493 DAC.

The chip above coax connector is from National Semiconductor and I cannot find any information on it.

Unless you mean that coax receiver is integrated into AKM DAC which would make a sense.

EDIT: If I am not mistaken SPDIF receiver is not integrated into AKM DACs but need external SPDIF receiver chip e.g. AK4113, AK4118 or similar. AKM requires registration before datasheet can be downloaded.

11 Reply by Tarking (edited by Tarking 2024-01-12 14:24:24)

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Re: Hiby R6 III DAP coax to ADI-2 DAC FS problem

Problem solved... kind of.

I purchased el cheapo Nedis SPDIF coaxial to Toslink audio converter. No problem with 24/96 kHz from R6 III. This solution is not optimal however. It remains to be seen how long this el cheapo (17 €) converter lasts and what its quality is like.

I also have ifi iDSD micro connected to my living room system via Intel NUC which serves as my music server and it has coaxial SPDIF input. It also accepts 24/96 kHz from R6 III.

I opened my Schiit Bifrost DAC which also detects 24/96 kHz from R6 III and it has AKM AK4113 SPDIF receiver chip.

Three out of four coaxial SPDIF input devices I have access to seems to work with R6 III and one (ADI-2 DAC FS v1) not at 24/96 kHz. This makes one wonder if there is something wrong with my ADI-2 DAC FS coaxial input circuit.

12 Reply by KaiS (edited by KaiS 2024-01-13 08:59:29)

  • KaiS
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Re: Hiby R6 III DAP coax to ADI-2 DAC FS problem

Tarking wrote:

…makes one wonder if there is something wrong with my ADI-2 DAC FS coaxial input circuit.

To exclude ADI-2 DAC’s Coax input is broken, test with any other source than the Hiby R6 III DAP.


A Google search “Hiby R6 III DAP RME ADI-2 DAC” did not reveal any reports about incompatibility between the two.

This user owns both, maybe you can ask to test:
https://www.head-fi.org/threads/hiby-r6 … t-17864891

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13 Reply by MC

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Re: Hiby R6 III DAP coax to ADI-2 DAC FS problem

Tarking wrote:

Three out of four coaxial SPDIF input devices I have access to seems to work with R6 III and one (ADI-2 DAC FS v1) not at 24/96 kHz. This makes one wonder if there is something wrong with my ADI-2 DAC FS coaxial input circuit.

As you most probably can't nor know anyone who could measure this your only chance to find out is by sending the DAC in. If this unit's coax input is a bit in-sensitive at higher sample rates, then this can be fixed.

Regards
Matthias Carstens
RME

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  • Registered: 2019-12-07
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Re: Hiby R6 III DAP coax to ADI-2 DAC FS problem

MC wrote:

As you most probably can't nor know anyone who could measure this your only chance to find out is by sending the DAC in. If this unit's coax input is a bit in-sensitive at higher sample rates, then this can be fixed.

Thanks. I will consider this option if I hear back from Head-Fi users with similar gear working normally.

If I choose to send my unit in for inspection how should I proceed? My unit is of course out of warranty now so this option can prove to be quite expensive.

15 Reply by MC

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Re: Hiby R6 III DAP coax to ADI-2 DAC FS problem

Where are you located?

Regards
Matthias Carstens
RME

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  • Registered: 2019-12-07
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Re: Hiby R6 III DAP coax to ADI-2 DAC FS problem

MC wrote:

Where are you located?

Finland.