Topping D50 III optical input bug with 44.1kHz files

[VientoB]

The problem now exists with many source devices, not just televisions. In recent years, the problem has also been occurring more and more frequently with CD players. A bit ridiculous when you consider that it was primarily developed for these devices.

You should look at what makes sense for you: DAC or Chromecast Audio replacement.
The usual alternatives are Wiim Mini or a Raspberry Pi with streamer software, there are now many options.

If you want to keep both, you could put an AK4118 board from Aliexpress in between. This has solved the problem with TVs for some people I know, but it doesn't have to work with Chromecast Audio.

Do you have a link to discussions of this problem, because I cannot find any.

 

[MaxwellsEq]

Do you have a link to discussions of this problem, because I cannot find any.

Search LG TV on ASR.

Also search on the AKM factory fire. AKM used to sell an optical receiver that coped well with incoming junk.

@Roland68 has summarised some of his analysis of the nonsense that LG TVs in particular insert into the bitstream.

 

[VientoB]

Search LG TV on ASR.

Also search on the AKM factory fire. AKM used to sell an optical receiver that coped well with incoming junk.

@Roland68 has summarised some of his analysis of the nonsense that LG TVs in particular insert into the bitstream.

Ok. But there doesn't seem to be anything on the Chromecast Audio doing that. And would it produce the skips in quiet passages?

 

[MaxwellsEq]

Ok. But there doesn't seem to be anything on the Chromecast Audio doing that. And would it produce the skips in quiet passages?

In post 38 @Roland68 said:

Chromecast Audio only ran with interruptions at 44.1k on my Sony DSC-88 (Digital Signal Checker) workshop device, which is why I returned it.

Admittedly only a single sample, though.

 

[unpluggged]

Search LG TV on ASR.

I can't see where the OP did say that their source is an LG TV, though. And still, FWIW, my LG TV has no issues outputting audio to a miniDSP Flex and to the RME ADI-2 Pro, so it's not so unambiguous here.

 

[MaxwellsEq]

I can't see where the OP did say that their source is an LG TV, though. And still, FWIW, my LG TV has no issues outputting audio to a miniDSP Flex and to the RME ADI-2 Pro, so it's not so unambiguous here.

OP didn't say they had an LG TV. You are absolutely correct.

They actually asked about a Topping-wide issue with optical inputs.

BUT since post #1 there have been some other side threads. Lots of people have asked about OP's sources. [This is because some of us suspect some Topping devices (especially without DPLL adjustments) are sensitive to optical S/PDIF junk.] We have learned OP has Chromecast Audio. One ASR expert has experienced issues when testing Chromecast Audio S/PDIF into a definitive piece of test gear. [They also mentioned LG TVs may be egregious - and so some of the reported Topping optical issues may actually be a reflection of LG TV output.]

 

[Roland68]

Search LG TV on ASR.

Also search on the AKM factory fire. AKM used to sell an optical receiver that coped well with incoming junk.

@Roland68 has summarised some of his analysis of the nonsense that LG TVs in particular insert into the bitstream.

I can't see where the OP did say that their source is an LG TV, though. And still, FWIW, my LG TV has no issues outputting audio to a miniDSP Flex and to the RME ADI-2 Pro, so it's not so unambiguous here.

Do you have a link to discussions of this problem, because I cannot find any.

Guys, I never said anything about LG TVs.

It affects many TV manufacturers, including Samsung, LG, etc., but not always all of their TVs.
In the same way, over the last 10-15 years, more and more source devices have appeared that have problems with SPDIF when connecting to DACs. This also includes many CD/DVD/BD players.
This can be due to the quality of the signal, the signal strength and deviations/non-compliance with the SPDIF standard.

It is noticeable that these TVs work without problems with soundbars, AV devices and speakers from their own company via SPDIF.

Since these problems also appeared a few years ago with TVs and other source devices among friends, I have checked the signal strength on some devices (it was only a problem once) and the signal integrity with the Sony DSC-88. If the DSC-88 does not output the signal properly, then the standard is not being met, and that was the case almost every time a DAC did not work.

Even AVRs and Wiims have problems with these sources.
This problem affects many DACs, not just those from Topping. But since Topping has a high market share with devices like the E30, it is of course noticed more often.

These problems are mostly reported in the forum under the DAC threads.
But on Google you only need to search for "DAC", "Toslink, optical, SPDIF or coax" and terms like "failure, problem, stuttering, interruption, dropout" etc.

 

[unpluggged]

I still think we are going in the wrong direction. I don't believe TV is at play here at all, since the unstable input is manifesting at 44.1 kHz and not at 48 kHz.

 

[VientoB]

These problems are mostly reported in the forum under the DAC threads.
But on Google you only need to search for "DAC", "Toslink, optical, SPDIF or coax" and terms like "failure, problem, stuttering, interruption, dropout" etc.

I did a quick google and cannot find anything that talks about only 44.1kHz files and mainly quiet passages. Also no mention of Chromecast Audio.

 

[JustJones]

Have you tried any other source like a CD/DVD player or TV connected to the Topping by optical to see if you can replicate the problem fed by other devices? If it has problems with other devices then I would think could be the DAC if not the maybe the chromecast.

 

[antcollinet]

I still think we are going in the wrong direction. I don't believe TV is at play here at all, since the unstable input is manifesting at 44.1 kHz and not at 48 kHz.

I don't thinik that has been suggested for this case - which is a chromecast. The suggestion is the chromecast might have a non compliant output - TV's have only been mentioned as devices that sometimes have similarly non compliant outputs, and as an example where some DACS can still work with a non compliant source, but others can't. And it is not the fault of those that can't IF the source is non compliant.

 

[MaxwellsEq]

I don't thinik that has been suggested for this case - which is a chromecast. The suggestion is the chromecast might have a non compliant output - TV's have only been mentioned as devices that sometimes have similarly non compliant outputs, and as an example where some DACS can still work with a non compliant source, but others can't. And it is not the fault of those that can't IF the source is non compliant.

Excellent summary.

If you have an incompetent transmitter and an intolerant receiver you may have a problem.

Intolerance of incompetent transmission is not a fault, but it is frustrating.

 

[phofman]

IMHO an incompatibility is a general term which actually represents some very specific technical issue/s. I wonder what such presumable incompatibility with SPDIF at 44.1kHz and not 48kHz does actually represent. SPDIF is a rather simple protocol and technology, it should not be difficult to locate the actual technical issue.

An incorrect preamble? 44.1kHz and 48kHz preambles with other params fixed differ only in a few bits https://en.wikipedia.org/wiki/S/PDIF#Protocol_specifications . Error in this field would likely not cause corrupted samples.

Incorrect frequency, outside of the SPDIF specified range? It is possible, that the transmitter clock generator does not generate correct frequency or too much of a jitter for the 44.1kHz samplerate. That would be a major fault, though IMO quite unlikely. Every SPDIF receiver reports locking to the incoming stream, troubleshooting should not be difficult. E.g. using SPDIF receivers in linux which have access to all registers of the SPDIF receiver and their drivers could be modified to report more info that they currently do. Dedicated SPDIF analyzers exist (e.g. digital input in AP analyzers would likely be able to report any issue with SPDIF input in detail).

I really wonder what specific technical issue can a transmitter be affected with to output 48kHz OK for all receivers and 44.1kHz not OK for some receivers (and this not OK be represented by short dropouts discussed by this thread). Perhaps just the stream frequency being outside of specs.

Any specific technical ideas?

 

[antcollinet]

48kHz OK for all receivers and 44.1kHz not OK for some receivers (and this not OK be represented by short dropouts discussed by this thread). Perhaps just the stream frequency being outside of specs.

This is one of the things I suspect. Some devices use two clocks - one for 44.1kHz and multiples, another for 48kHz and multiples. It is possible one could be out of spec.

Or possibly (more likely) trying to derive a 44.1kHz clock from one that is a multiple of 48kHz, resulting in it being insufficiently accurate for 44.1.

 

[Rja4000]

I've done more trials and definitely can NOT reproduce the issue.

See more here.

I have a pair of Chromecast audio somewhere.
If time allows, I'll give it a try.

 

[VientoB]

I've done more trials and definitely can NOT reproduce the issue.

Fair enough, so far the voting is 2:1 though.

 

[Rja4000]

Fair enough, so far the voting is 2:1 though.

Which doesn't mean anything.

Would be nice to know who has the issue and to get more details about setup:
Exact source and circumstances, firmware version, specific DAC settings,...

 

[VientoB]

Which doesn't mean anything.

Would be nice to know who has the issue and ti get more details about setup:
Exact source and circumstances, firmware version, specific DAC settings,...

Well I agree. I have asked one of the people in the main thread but he hasn't replied to me yet.

 

[Sokel]

Maybe irrelevant because a different DAC but I tried 3 TVs (one brand new one LG,an older Samsung and an even older LG) with Khadas TB.
I tried any signal possible from 44.1kHz to 96kHz and I could constantly reproduce problems (big or small,ie from inaudible to mayhem) with a DPLL bandwidth lower than 8 (low-medium for whatever that means) for the newer ones but not the oldest TV (15+ years old)

It seems that the problem OP has here is different,as at my test amplitude of the signal didn't matter.

 

[VientoB]

Yeah I'm going to try to do a short video this evening