Optical or Coax, Cheap or Expensive?

[Mehdiem]

Hi Folks. I’m currently connecting my Node Streamer to RME ADI-2 using an inexpensive optical cable bought from Amazon (FosPower). I'm wondering (1) whether optical sounds better or Coax? (2) upgrading my cable to a more expensive version (i.e AudioQuest cable) would result in improving the quality, or digital is digital, AKA 0-1, and hence it makes no difference, as long as data is transmitted?

 

[RickSanchez]

The answer to both #1 and #2 is "no". (Buying AudioQuest cables is never a good idea, for any reason.)

That said, I believe coax supports a higher bandwidth: 24-bit/192kHz if I'm not mistaken. I think optical only goes up to 96kHz. I can't imagine you could hear the difference once sample rates are that high, but I suppose if it matters to you that the full signal is making it across to your RME ADI-2 then coax is the way to go.

Other ASR members more knowledgeable than me in this area can correct me if I'm off base here.

 

[radix]

With digital, usually it either works or it does not. I would not go expensive digital cables.

If you have ground loop problems, then optical is the way to go. Otherwise, coax is just fine. Coax might work better for super high sample rates, if you use those.

 

[LTig]

@radix is correct, with almost all DACs (there may be DACs with a broken design where incoming jitter is not suppressed enough but I haven't seen one yet where jitter was so high to become audible) the type of cable has no influence on the sound as long as its bandwidth is sufficient.

That said Toslink will always work up to 96 kHz sample rate. It may work up to 192 kHz sample rate if both transmitter and receiver chip support it. The RME does. In all cases finally the length of the cable is the limiting factor. 48 kHz sample rate can work up to 10 m in my experience.

 

[Mehdiem]

@radix is correct, with almost all DACs (there may be DACs with a broken design where incoming jitter is not suppressed enough but I haven't seen one yet where jitter was so high to become audible) the type of cable has no influence on the sound as long as its bandwidth is sufficient.

That said Toslink will always work up to 96 kHz sample rate. It may work up to 192 kHz sample rate if both transmitter and receiver chip support it. The RME does. In all cases finally the length of the cable is the limiting factor. 48 kHz sample rate can work up to 10 m in my experience.

Your noted "bandwidth". How can I check the bandwidth in the specifications of the cable? For example, could a regular RCA cable function properly as a coax cable? Or the thickness matters?

 

[LTig]

Your noted "bandwidth". How can I check the bandwidth in the specifications of the cable? For example, could a regular RCA cable function properly as a coax cable? Or the thickness matters?

The bandwidth of proper coax cables is far higher than required for all digital audio transmission. It's different with Toslink cables and here I have no advice other than trying to find specifications of the maker. If in doubt for longer cables choose one using a thin glass core, most use a thicker plastic core.

 

[Digitaltrader]

That said Toslink will always work up to 96 kHz sample rate. It may work up to 192 kHz sample rate if both transmitter and receiver chip support it.

Where might I find out if the xmit/rcv chips support 192 kHz? For example my Wiim Mini to a Topping D50s? Is it as simple as checking the unit specs, or would I need to find which chips are used and then get specs on those? Thanks.

 

[AudiOhm]

Since both units have optical and coax, use both then switch between them and try both out.

As for cost, there is no evidance that a more expensive cable sounds better...

I have an Anthem pre/pro, I run all connections possible from my input devices to the pre/pro. Then switch between them and listen to the one I like best.

So far in a blind test I have no idea what cable is selected...

Ohms

 

[LTig]

Where might I find out if the xmit/rcv chips support 192 kHz? For example my Wiim Mini to a Topping D50s? Is it as simple as checking the unit specs, or would I need to find which chips are used and then get specs on those? Thanks.

Check the manual of both units you want to connect. Only then you can rely on it to work.

 

[valerianf]

The advantage of an optical cable is that you avoid any ground loop.
You can use the cheapest that you find.

 

[MRC01]

Sometimes the cables & switches quote bandwidth in terms of data, not frequency. Data bandwidth is total bits / second with some overhead for SPDIF packet overhead.
For example CD is 44100 samples * 2 channels * 16 bits = 1,411,200 bits / sec = 1.4112 Mbps
192-24 is 192000 samples * 2 channels * 24 bits = 9,216,000 bits / sec = 9.216 Mbps
And you need a bit more than that for overhead. Toslink often does work reliably at 192-24 with modern high quality gear, just not with all gear or cables. IME, the cheapest toslink cables don't work above 48-24. Good ones work up to 192-24 with equipment that supports it. Good doesn't mean super expensive.