Coax v/s Optical (toslink)

[P_M]

I searched but couldn't find anything conclusive here. Have there been any tests and measurements done to see if there is any difference in performance between rca coax v/s optical toslink cables ? It would be good to see tests comparing both upto high bandwidth (like 32 bit and 192Khz, or multiple channels) to see which type of medium stands up to the task. Or what is the limit of each medium.

 

[Vini darko]

From what I've seen seen since joining in the measuments. It's not the cables but the quality of implementation of the dac that matters.

 

[pozz]

For SPDIF over optical aka TOSLINK the limit is 96kHz. Over coax it's 192kHz. Max bit depth for both is 24 bits. IIRC this is only for stereo PCM. For multichannel I don't know.

 

[P_M]

you mean 96khz 24bit is the limit of the medium (optical connection and cable) ? And coax can go up to 192Khz ?

 

[Pat]

Sorry not true, optical can do 192khz 24 bit - I feed this rate/depth from my PC to an Emotiva PT-100 and it works great.

 

[pozz]

Yes. Those are stereo PCM limits. Multichannel will likely require compression (AC3 or something like it). I don't do HT stuff so I never looked into it.

 

[pozz]

Sorry not true, optical can do 192khz 24 bit - I feed this rate/depth from my PC to an Emotiva PT-100 and it works great.

It wasn't designed for that kind of bit rate. 48kHz tops originally if I remember right.

 

[Blumlein 88]

It wasn't designed for that kind of bit rate. 48kHz tops originally if I remember right.

No some later units were designed to do 192 khz.

 

[Blumlein 88]

In answer to the OP.
https://www.audiosciencereview.com/...l-converters-introduce-jitter.2279/post-62260

And the following post.
https://www.audiosciencereview.com/...l-converters-introduce-jitter.2279/post-62262

There is no difference in jitter from just the cable vs optical cable.

In the latter, I used a V-link USB to SPDIF converter that had both toslink and coax output. Same clock for both outputs. The resulting J-test signal was identical. In the particular gear I had there is no difference in noise or distortion (not shown in that particular post).

As to limits of the medium, that depends on details of design mainly. Most Toslink doesn't attempt to go beyond 96 khz. It can however just isn't asked to do so. ADAT Lightpipe in pro audio used the same cables, connectors etc as Toslink though a different data format. It from the beginning could do 8 channels of 48khz/24 bit. Which is the same data amount as 192/24.

The optical converters are better than the old Toshiba units, and even cheap optical cable has improved. So Toslink can be just fine for connecting, and coax doesn't offer any advantage if you don't need the super high data rates. Toslink offers the advantage of removing the chance for hum to travel between two pieces of gear.

 

[Tup3x]

I'm somewhat surprised that SPDIF has been stuck at 24-bit 192 kHz. I'd imagine that it wouldn't be much of a problem to increase the bandwidth nowadays without massive cost increase.

 

[Jimbob54]

For SPDIF over optical aka TOSLINK the limit is 96kHz. Over coax it's 192kHz. Max bit depth for both is 24 bits. IIRC this is only for stereo PCM. For multichannel I don't know.

I need to check when I get home, but I'm pretty sure my smsl m500 shows up to 192 qobuz via roon via a Cambridge cxnv2 over optical out from the cxn.

I'll try casting from qobuz app over chromecast audio optical out too, but think I've seen that at 192 also

 

[pozz]

I'm obviously behind the times.

 

[Blumlein 88]

I'm somewhat surprised that SPDIF has been stuck at 24-bit 192 kHz. I'd imagine that it wouldn't be much of a problem to increase the bandwidth nowadays without massive cost increase.

Plenty of dacs do 384 and 768 khz.

 

[vhild§]

Now that I´ve been reading about cheap dacs, it seems they don´t do coaxial or optical as well as they do usb in. As I´ll be mainly using the external dac connected to a cd player, are there any decent cheapish dacs that could be recommended for that role?

 

[cochlea]

Sorry to bring up an old thread, but when I did a search this subject seemed to be very relevant. I want to run a cable from a Bluenode 2i to an E30 dac. The run is about 30ft. Would coax or Toslink be the better choice for this? Thanks in advance for the help!

 

[Blumlein 88]

Officially Toslink is for up to 5 meters. Usually it is fine to 10 meters (33 ft) and with newer gear I have seen it work longer.

SPDIF over coax is good for at least 10-15 meters and I've used it at 15 meters (49 ft) lots of times. So I would go with a good RG6 coax.

 

[abdo123]

Toslink can break ground loops which makes it the king of transport.

 

[cochlea]

Thank you for the quick replies. I think I’ll try the coax first, and if there is a problem I’ll try the toslink.

 

[Krazywaffle]

This has proven to be a very informative thread as I have been trying to figure out which method of connection between Mac mini (music server) and Meridian 568.2mm Processor is best:

(1) Mac mini > Toslink > Meridian 568.2mm (currently used)
(2) Mac mini > USB > Singxer SU-1, Gustard U16, or Schiit EITR > SPDIF > Meridian 568.2mm (considered “upgrade”)

Given that various tests show that the implantation within the DAC/Processor is paramount I am leaning towards continuing to use Toslink as the Meridian unit uses high quality implementation and is specifically designed to de-jitter incoming digital signals and upscale everything to 24/96.

Just not sure there are actual (audible) advantages to the asynchronous connection provided by USB-to-SPDIF conversion (e.g., Singxer SU-1, Gustard U16, Schiit EITR) over a straight Toslink connection into a well-implemented DAC/Processor?

 

[BitPerfect_]

I need to check when I get home, but I'm pretty sure my smsl m500 shows up to 192 qobuz via roon via a Cambridge cxnv2 over optical out from the cxn.

I'll try casting from qobuz app over chromecast audio optical out too, but think I've seen that at 192 also

Interesting, would you please share with us the results?
Thanks,