unpluggged
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How the TVs were connected? I mean, the KTB has no optical input...Khadas TB.
How the TVs were connected? I mean, the KTB has no optical input...Khadas TB.
Coaxial of course,SPDIF doesn't care.How the TVs were connected? I mean, the KTB has no optical input...
..and a little noise too.You do tend to get different jitter profiles with them.
Strange! Perhaps it's a poorly performing clock that's too marginal at 44kHz for the DAC to reliably extract a good clock feed.Posting an update as I seem to have possibly solved this issue by trying my other Chromecast Audio (I have two) with the D50 III. So far no drop outs with 44.1 kHz music. So it seems to be a problem with my original Chromecast Audio, but only with this DAC. Very strange that it's only with 44.1kHz music though.
I'm gonna bet it has a crystal at a multiple of 48kHz, and is trying to derive the 44.1 imperfectly from that. Whereas all the other most used sample rates (48, 96 etc can be derived perfectly.Strange! Perhaps it's a poorly performing clock that's too marginal at 44kHz for the DAC to reliably extract a good clock feed.
Probably rules that theory out then.88.2 kHz was fine, though
This indicates poor quality or a defect. You would need a suitable analyzer for analysis, but it's not worth the effort.Update.
I got a new optical cable which seems to have solved the problem. The old cable still works with my SMSL DAC but was playing up with the Topping used with both Chromecast Audios.
Very unsure why only 44.1kHz is affected though.
TOSLink uses cheap plastic fiber.This indicates poor quality or a defect. You would need a suitable analyzer for analysis, but it's not worth the effort.
Often, cheap optical fibers made of cheap plastic fibers (POF) are used instead of real glass fiber optic cables.
Polymer optical fibers, although much cheaper, are more complex and offer more sources of error during production. The transmission performance is generally poorer, and POF cables also have higher attenuation, but this shouldn't matter given the low transmission rates in the audio range.
Real glass fiber optics, on the other hand, are more expensive, stiffer, and mechanically more sensitive.
As a blanket statement, that's definitely wrong.TOSLink uses cheap plastic fiber.
Can you suggest a cable of known quality?As a blanket statement, that's definitely wrong.
The truth would be that nowadays, almost exclusively cheap plastic fiber optic cables are used, often even cheaper than POF and of very simple processing (without any quality). These plastic fibers are usually just cut and not polished.
I still own several older fiber optic cables with genuine quartz glass fibers. Some of them even came with devices.
But there are still several manufacturers of Toslink cables with genuine quartz glass fibers, with prices starting at around €/$40 per meter.
There's absolutely nothing wrong with a genuine POF Toslink cable with a polished surface.
Honestly, I can't really recommend much at the moment.Can you suggest a cable of known quality?
Given that my setup never had a problem using a Chord Mojo and SMSL DAC, would that not point to the Topping being the slightly dodgy item? Worth noting the problem has been fixed by changing the cable.I'm using very simple and cheap POF cables that are sold under the brand name "LogiLink" and I never had problems.
They are a bit stiff, but the connectors sit firmly and the surfaces do look OK.
Fibers:
Attenuation usually is not an issue except for very long fibers.
Multimode fibers like the extremely thick Toslink do add jitter (due to mode dispersion), but this is irrelevant at frequencies used for Toslink. This is why high-speed transmission links use monomode fibers.
The limiting factor for Toslink regarding speed is that it uses LEDs (not lasers) and these have considerable rise/fall times. These will cause so called "Inter-Symbol-Interference" (ISI) and thus jitter.
The performance of LEDs can vary quite a bit depending on technology.
Post #53 mentioned the cause that sounds most likely to me: clock outside specification on either sending or receiving side.
I once borrowed a DAC from a friend and it did only work without stuttering with 44.1 kHz with one specific source (my TV).
When using other SPDIF sources (among them a RME FF UC) it did not manage to achieve a stable lock.