What is the best Digital Interface for High End Audio? USB? S/PDIF? Does it Matter?

caesar

Well-Known Member
May 30, 2010
4,290
767
1,698
What is the best Digital Interface? USB or S/PDIF?

Or does it really matter whether it's USB or S/PDIF, assuming you are using a quality, high end DAC?
 

Audioseduction

Well-Known Member
Dec 6, 2010
178
8
925
FLORIDA
From my personal experience it does. I prefer ST Optical Glass Fiber myself.
 

Thetiminator

Well-Known Member
Apr 20, 2015
86
19
238
I agree that USB is far from the best interface. IME I find a USB/SPDIF converter in the chain always improves the sound.

My custom made server outputs via fibre optic (or fiber seeing that I'm speaking to the U.S) as I was assured it was the best way to go. I don't have any experience of AT&T Glass but I'd imagine it's very similar to my set up. In order from my experience:

Fibre optic
AES/EBU
Digital coax
USB
Toslink
 

edorr

WBF Founding Member
May 10, 2010
3,139
14
36
Smyrna, GA
I don't think there is a generically valid single answer to this quesiton. It is systems dependent. Based on my experience, #1 would be ethernet streaming, #2 USB. I will sound take possession of a server that has I2S card, and also have an AES/EBU source. Whatever I end up preferring may not work best in other systems.
 

Fitzcaraldo215

New Member
Nov 3, 2014
394
2
0
What is the best Digital Interface? USB or S/PDIF?

Or does it really matter whether it's USB or S/PDIF, assuming you are using a quality, high end DAC?

Wrong question. The right question concerns the DAC. Choose the DAC that you like and it will likely determine which way it can connect. Most only have one way. But, the DAC is much more important than the computer, O/S, cables or anything else.

I agree it is hard to generalize, but I prefer asynchronous USB - regular USB is almost dead these days in the marketplace, but the same USB cables are used in either case. Properly implemented, asynch USB has zero jitter.
 

Bruce B

WBF Founding Member, Pro Audio Production Member
Apr 25, 2010
7,006
512
1,740
Snohomish, WA
www.pugetsoundstudios.com
The professionals that record and master your albums use:
ST-optical
AES/EBU
MADI
Ethernet
 

jeromelang

Well-Known Member
Dec 26, 2011
433
66
935
My experiences with the TSDX and DAC2X showed me the ST Optical cables are (highly) directional, different lengths do matter (1m vs 4m lengths), and that there could even be sonic differences between 2 cables of the same brand, and the same lengths.

Could this be due to the varying air gap distances between connecting joints?

Who knows?

But I'm not very keen on applying opti-gel between the connecting joints.
 

Bruce B

WBF Founding Member, Pro Audio Production Member
Apr 25, 2010
7,006
512
1,740
Snohomish, WA
www.pugetsoundstudios.com
My experiences with the TSDX and DAC2X showed me the ST Optical cables are (highly) directional, different lengths do matter (1m vs 4m lengths), and that there could even be sonic differences between 2 cables of the same brand, and the same lengths.

Could this be due to the varying air gap distances between connecting joints?

Who knows?

But I'm not very keen on applying opti-gel between the connecting joints.


My experience has been different. I've used 1m and up to 100' with no detectable difference.
 

Phelonious Ponk

New Member
Jun 30, 2010
8,677
23
0
My experience has been different. I've used 1m and up to 100' with no detectable difference.

Do you find them to be directional? That one is a bit mysterious...

Tim
 

DonH50

Member Sponsor & WBF Technical Expert
Jun 22, 2010
3,947
306
1,670
Monument, CO
It makes sense if the electrical side is messed up inside one of the components. If length is also a factor at such low lengths I suspect the receiver in one of the components is bad. Or just dirty...
 

caesar

Well-Known Member
May 30, 2010
4,290
767
1,698
Wrong question. The right question concerns the DAC. Choose the DAC that you like and it will likely determine which way it can connect. Most only have one way. But, the DAC is much more important than the computer, O/S, cables or anything else.

...

Not really. The new CA architecture that has evolved is more complex, with decoupled tasks and dedicated boxes, such as streamers, servers, dacs, etc., which frequently outperform the laptop computer most use today.

And it’s more than just the dac you like. What if you find a better dac? What if other components in your system change breaking up synergy? What if you start to prefer a different flavor in your dac? Or what if there is a technological advance you want to take advantage of, and need to swap out some components in this new CA architecture? So depending on the digital components you choose, you don't want to get locked in.
 

Audioseduction

Well-Known Member
Dec 6, 2010
178
8
925
FLORIDA
Do you find them to be directional? That one is a bit mysterious...

Tim

No they are not. When I was in IT and installing fiber their was no such thing as directional. That's very funny!
 

jeromelang

Well-Known Member
Dec 26, 2011
433
66
935
I didn't hear a difference directionally either. I am using the garden variety orange cables you get from Fry's.


I am using the stock orange colour cables, provided by emm lab.

I also bought 2 pairs of 4 meters from that link you provided previously.

All 5 pieces are directional. Meaning they sound better connected only in one direction, and not the other.
The changes in soundstage height, width, and depth, plus soundstage perspective is unmistakeably audible.
All the 4 meter cables sounded "slow" compared to the stock, and imaging tend to be effusive and vague.

A fellow user of the TSDX / DAC2X brought over his original stock cable to my place and his cable also proved to be directional as well. (We subsequently found that he had been using it in the wrong direction...)

Both our stock cables sound slightly different, though the degree of difference is not as great as comparing between 1m vs the 4m lengths.

We were both contemplating - what if we apply the opti gel?
Will it even out the differences?

Anybody who has ever use any opti gel gel to maintain consistent refraction index please do share your experiences.

And also, does the gel ever get dried up?

If so, how to clean out the dried out jelly?????
 
Last edited:

Fitzcaraldo215

New Member
Nov 3, 2014
394
2
0
Not really. The new CA architecture that has evolved is more complex, with decoupled tasks and dedicated boxes, such as streamers, servers, dacs, etc., which frequently outperform the laptop computer most use today.

And it’s more than just the dac you like. What if you find a better dac? What if other components in your system change breaking up synergy? What if you start to prefer a different flavor in your dac? Or what if there is a technological advance you want to take advantage of, and need to swap out some components in this new CA architecture? So depending on the digital components you choose, you don't want to get locked in.

Not following you. There is always something better, but you always need a DAC. If your chosen DAC locks you into, say, USB, then so be it, temporarily. If you change your mind and later select a coax input DAC, it is not the end of the world. Get new cables and a coax output card to support that. I do not see why you are permanently locking yourself in. The advantage of computer based playback is flexibility and modifiability. You are locking yourself in just as much if you start with a coax only DAC. And, it might not be worthwhile to limit yourself to a DAC that can do both, either sound quality or cost-wise.

But, if maximum flexibility is what you want, then USB has a clear edge. My take is that there are many more USB DACS, especially Asynch USB, than coax or other interfaces, especially among newer ones.

And, I still maintain that the DAC has the greatest impact on sound. It alone converts digital data transfers to analog signal, each DAC having its own sonic signature or lack thereof. And, better DACS are more insulated from noise coming from the computer or the cables, hubs, etc. that might adversely influence the analog output. Also, there is much more available in add-on devices to shield the DAC from noise via USB than coax, if necessary, including galvanic isolation if you need it. I do not see that in coax.
 

DonH50

Member Sponsor & WBF Technical Expert
Jun 22, 2010
3,947
306
1,670
Monument, CO
I am using the stock orange colour cables, provided by emm lab.

I also bought 2 pairs of 4 meters from that link you provided previously.

All 5 pieces are directional. Meaning they sound better connected only in one direction, and not the other.
The changes in soundstage height, width, and depth, plus soundstage perspective is unmistakeably audible.
All the 4 meter cables sounded "slow" compared to the stock, and imaging tend to be effusive and vague.

A fellow user of the TSDX / DAC2X brought over his original stock cable to my place and his cable also proved to be directional as well. (We subsequently found that he had been using it in the wrong direction...)

Both our stock cables sound slightly different, though the degree of difference is not as great as comparing between 1m vs the 4m lengths.

We were both contemplating - what if we apply the opti gel?
Will it even out the differences?

Anybody who has ever use any opti gel gel to maintain consistent refraction index please do share your experiences.

And also, does the gel ever get dried up?

If so, how to clean out the dried out jelly?????

I'd love to see a BER test showing differences in directionality. Unless there is something wrong that cannot happen. That said I am not familiar with ECC on these links.

I would not use gel on TOSLINK but feel free to see if it further improves the sound and/or reduces differences among cables and directionality. And yes it can dry out. It will flake off and you have to use some sort of cleaning agent and potentially repolish the ends.
 

jeromelang

Well-Known Member
Dec 26, 2011
433
66
935
In an optical connector, where the 2 fiber are connected butt to butt, there will be a small air gap between the butt ends of the fibers.







That air gap will have a refractive index different from the fibers, and these variations in refractive index at the optical connectors will induce some reflection of the light being conducted, which in turn will give rise to increased jitter upon reception.

I believe this is what causing me to hear very audible differences whenever the directionality is changed, because what I had done probably was changing the amount of air gap at either end...!?!?!




The opti gel that I was talking about is more commonly called an 'index matching fluid' in the fiber optics industry.

What a good index matching fluid does is to fill that air gap with a substance having a refractive index closer to that of the optical fiber. Such fluids are commonly used in the telecom industry. Just do a google search.




Looks like the ST Optical interface is not such a "perfect" digital interface after all......
 
Last edited:

joaovieira

Well-Known Member
Feb 16, 2013
390
270
970
Brazil
Not following you. There is always something better, but you always need a DAC. If your chosen DAC locks you into, say, USB, then so be it, temporarily. If you change your mind and later select a coax input DAC, it is not the end of the world. Get new cables and a coax output card to support that. I do not see why you are permanently locking yourself in. The advantage of computer based playback is flexibility and modifiability. You are locking yourself in just as much if you start with a coax only DAC. And, it might not be worthwhile to limit yourself to a DAC that can do both, either sound quality or cost-wise.

But, if maximum flexibility is what you want, then USB has a clear edge. My take is that there are many more USB DACS, especially Asynch USB, than coax or other interfaces, especially among newer ones.

And, I still maintain that the DAC has the greatest impact on sound. It alone converts digital data transfers to analog signal, each DAC having its own sonic signature or lack thereof. And, better DACS are more insulated from noise coming from the computer or the cables, hubs, etc. that might adversely influence the analog output. Also, there is much more available in add-on devices to shield the DAC from noise via USB than coax, if necessary, including galvanic isolation if you need it. I do not see that in coax.

Agree. Perfect for me.
 

caesar

Well-Known Member
May 30, 2010
4,290
767
1,698
Not following you. There is always something better, but you always need a DAC. If your chosen DAC locks you into, say, USB, then so be it, temporarily. If you change your mind and later select a coax input DAC, it is not the end of the world. Get new cables and a coax output card to support that. I do not see why you are permanently locking yourself in. The advantage of computer based playback is flexibility and modifiability. You are locking yourself in just as much if you start with a coax only DAC. And, it might not be worthwhile to limit yourself to a DAC that can do both, either sound quality or cost-wise.

But, if maximum flexibility is what you want, then USB has a clear edge. My take is that there are many more USB DACS, especially Asynch USB, than coax or other interfaces, especially among newer ones.

And, I still maintain that the DAC has the greatest impact on sound. It alone converts digital data transfers to analog signal, each DAC having its own sonic signature or lack thereof. And, better DACS are more insulated from noise coming from the computer or the cables, hubs, etc. that might adversely influence the analog output. Also, there is much more available in add-on devices to shield the DAC from noise via USB than coax, if necessary, including galvanic isolation if you need it. I do not see that in coax.

It's the other components in the architecture that can lock you in, such as the music server, which may impact the ability to access your entire music library.
 

About us

  • What’s Best Forum is THE forum for high end audio, product reviews, advice and sharing experiences on the best of everything else. This is THE place where audiophiles and audio companies discuss vintage, contemporary and new audio products, music servers, music streamers, computer audio, digital-to-analog converters, turntables, phono stages, cartridges, reel-to-reel tape machines, speakers, headphones and tube and solid-state amplification. Founded in 2010 What’s Best Forum invites intelligent and courteous people of all interests and backgrounds to describe and discuss the best of everything. From beginners to life-long hobbyists to industry professionals, we enjoy learning about new things and meeting new people, and participating in spirited debates.

Quick Navigation

User Menu

Steve Williams
Site Founder | Site Owner | Administrator
Ron Resnick
Site Co-Owner | Administrator
Julian (The Fixer)
Website Build | Marketing Managersing