Dedicated PCI/PCIE digital audio transport

[DonH56]

Asynchronous USB DACs do use the DAC's internal clock, isolated from the incoming data stream, to provide much lower jitter.

S/PDIF or AES (the "pro" version of S/PDIF) systems capture the clock from the incoming data stream, which is generally much noisier.

AES is balanced. See e.g. https://en.wikipedia.org/wiki/S/PDIF

External USB DACs offer superior performance because they can more readily isolate the device from the power and ground noise of the system as well as buffer the data to use an independent "quiet" clock inside the DAC itself.

Professional AES systems sometimes use a master clock source to maintain synchronicity among multiple recording and playback modules since multiple tracks must all stay in sync during recording and playback (mixing, mastering, etc.) Here is an example of one such master clock unit: http://www.apogeedigital.com/products/big-ben It is great but costs about $1500.

There's a reason you are having trouble finding a consumer unit like that; it is not required to achieve outstanding performance, will have poorer performance than consumer USB DACs unless you pour a lot more money into it, and there is simply no market for it. Eventually you may find what you seek, but most of us are not aware of such and are not really interested in looking since we have better solutions, so cannot help your quest.

 

[Blumlein 88]

I get it guys, USB is much better because of the clock at the DAC. DBT experiments show no difference between connections. I've heard this stuff before several times. I'm also familiar with things like level matching, subjective bias, audibility threshholds for electronics. That most electronics including DACs, amps, and things like that easily exceed audibility threshholds and what really matters is the room acoustics, and speakers. etc.


Now one thing of interest is....is there a way to not use the DACs clock? Is such a thing even possible? I've heard of "world clocks". How do they work? Do they offer a benefit in terms of actual jitter performance?
Also is there such a thing as a balanced digital output? From what I gather AES is not balanced.

Okay, AES/EBU on XLR cables is balanced. I think it carries a 5 volt peak to peak signal. SPDIF over coax is unbalanced and is .5 volts peak to peak. Both along with Toslink are part of the AES3 standard.
https://en.wikipedia.org/wiki/AES3

Word clocks were developed to allow multiple digital devices to synch onto the same master clock. The clocks in digital audio devices vary slightly in speed. Even a few parts per million can lead to enough difference that mixing such devices will leave them out of synch with each other. Not good for mixing audio tracks. So a word clock uses a 75 ohm coax to distribute a master clock which all the slave devices use so that each sample occurs at the same time on all devices. Word clocks won't even have audio data they are just a stream for synchronized timing of sample rates.

Now some have pushed the idea that distributing a super accurate low jitter word clock to other devices will give them super low jitter. Without getting into the grimy details this is not usually true. Even with a word clock a PLL will have to keep the local device using the distributed clock. PLLs can work extremely well, but most of the time a local clock crystal right next to the DAC will have lower jitter than a PLL recovered clock off a word clock input. Here is an article with tests of the idea. Good explanation of word clocks too in that article.

https://www.soundonsound.com/techniques/does-your-studio-need-digital-master-clock

One of the results of that testing is that even very inexpensive devices have lower jitter using a local crystal based clock next to the DAC than using a word clock from a highly accurate master clock. The reason being effects of distributing the clock and the need to use PLL's with external clocking.


Now trying to be nice. Not suggesting this isn't the place for you. Yet honestly I am lost for your aims here. You say you know about blind testing, bias, thresholds etc. We have given you good reason the device you are asking about isn't going to be available. Plus why it would be technically inferior to USB. So it is unclear how we might be of help to you. Or why you wish to avoid USB connections.

I think most of us have been there where we listen, we hear, we experience something like USB doesn't sound good. It is a real experience. Yet some objectivity and distancing from our fallible subjective experiences we can learn those experiences mislead us. You still can't get over how you feel from those experiences sometimes. Or at least not easily. So is this a case where you heard USB not sound good and despite all the evidence otherwise you simply have this feeling something is wrong with it? If so okay. Maybe you can learn from us or maybe you don't wish to do so. That too is okay. We just need to be honest with each other so we can communicate effectively.

Despite some audiophile nervosa to the contrary, USB is a fabulous way to connect digitally because it gives lowest possible jitter. Because it isolates the digital device from the PC extremely well (except for a few very poorly designed devices). The success of that is why much pro gear has migrated to this solution. You also have thunderbolt and ethernet in some devices too. They all share the benefit of putting the clocking in the hands of a local crystal clock. The timing of the data stream has been divorced from the actual clocking of the DAC and that is a very good thing.

 

[March Audio]

Now trying to be nice. Not suggesting this isn't the place for you. Yet honestly I am lost for your aims here. You say you know about blind testing, bias, thresholds etc. We have given you good reason the device you are asking about isn't going to be available. Plus why it would be technically inferior to USB. So it is unclear how we might be of help to you. Or why you wish to avoid USB connections.

.

Garbulky, I can only re-iterate the above. We have told you all we can. The information is verifiable elsewhere. I think we are all a bit a bit of a loss as to what else we can tell you, or help you with. We dont understand your negative attitude to USB.

 

[garbulky]

Okay, AES/EBU on XLR cables is balanced. I think it carries a 5 volt peak to peak signal. SPDIF over coax is unbalanced and is .5 volts peak to peak. Both along with Toslink are part of the AES3 standard.
https://en.wikipedia.org/wiki/AES3

Word clocks were developed to allow multiple digital devices to synch onto the same master clock. The clocks in digital audio devices vary slightly in speed. Even a few parts per million can lead to enough difference that mixing such devices will leave them out of synch with each other. Not good for mixing audio tracks. So a word clock uses a 75 ohm coax to distribute a master clock which all the slave devices use so that each sample occurs at the same time on all devices. Word clocks won't even have audio data they are just a stream for synchronized timing of sample rates.

Now some have pushed the idea that distributing a super accurate low jitter word clock to other devices will give them super low jitter. Without getting into the grimy details this is not usually true. Even with a word clock a PLL will have to keep the local device using the distributed clock. PLLs can work extremely well, but most of the time a local clock crystal right next to the DAC will have lower jitter than a PLL recovered clock off a word clock input. Here is an article with tests of the idea. Good explanation of word clocks too in that article.

https://www.soundonsound.com/techniques/does-your-studio-need-digital-master-clock

One of the results of that testing is that even very inexpensive devices have lower jitter using a local crystal based clock next to the DAC than using a word clock from a highly accurate master clock. The reason being effects of distributing the clock and the need to use PLL's with external clocking.


Now trying to be nice. Not suggesting this isn't the place for you. Yet honestly I am lost for your aims here. You say you know about blind testing, bias, thresholds etc. We have given you good reason the device you are asking about isn't going to be available. Plus why it would be technically inferior to USB. So it is unclear how we might be of help to you. Or why you wish to avoid USB connections.

I think most of us have been there where we listen, we hear, we experience something like USB doesn't sound good. It is a real experience. Yet some objectivity and distancing from our fallible subjective experiences we can learn those experiences mislead us. You still can't get over how you feel from those experiences sometimes. Or at least not easily. So is this a case where you heard USB not sound good and despite all the evidence otherwise you simply have this feeling something is wrong with it? If so okay. Maybe you can learn from us or maybe you don't wish to do so. That too is okay. We just need to be honest with each other so we can communicate effectively.

Despite some audiophile nervosa to the contrary, USB is a fabulous way to connect digitally because it gives lowest possible jitter. Because it isolates the digital device from the PC extremely well (except for a few very poorly designed devices). The success of that is why much pro gear has migrated to this solution. You also have thunderbolt and ethernet in some devices too. They all share the benefit of putting the clocking in the hands of a local crystal clock. The timing of the data stream has been divorced from the actual clocking of the DAC and that is a very good thing.

Thanks for that info. I used to be very interested in getting an asynch usb dac for that reason. Previously my DAC was the XDA-1 and I didn't have SPDIF out. So my option was a USB output which wasn't asynch. I wasn't a fan of it but it was what I had. I did later encounter and try several DACs that use USB asynch.
Like the Geek Pulse Infinity, XDA-2, Emotiva DC-1 (which I use).

So to answer your question as to my aims. My aim in the thread was really to find what I mentioned. But as mentioned, looks like there is no such thing. So that is an answer. I appreciate everybody's help here in trying to find it. Also I don't think it was in vain. I feel like I learned stuff about world clocks, and that AES is balanced - which is different from what I was told. So that's good.

As I've mentioned, I am a subjective person and I recognize that I am in a science forum. I grant that's kind of confusing.

I don't plan on debating why I am not following a more objective way of doing things here. I think that would be bad form. I'm in a science forum after all!

Either way I don't think I would have anything useful to say on the subject for this forum if I did. I doubt I'm on the technical level to talk about that stuff either.

I'm not here to tell the audio science review what to do or how to think. And neither am I here to be told the same thing either. Some people enjoy schooling others. I'm not that student - especially if it's about things I didn't ask for. One of the most baffling things I am told is that I don't hear what I hear because of x reason. I tend to find little usefulness to those comments.

I'm just here to participate, learn stuff that's of interest to me, and have a good time. So I hope that makes sense. I'm getting the impression that maybe my presence is maybe a negative here. I don't know. It's my first time on a audio science forum.

I joined because I found it refreshing that somebody was making measurements and pointing out things they needed improvements. I've become a little bored of the standard that's being pursued in the higher end stuff. So I'm interested if somebody is pursuing high performance. So I'll read their stuff.

Hope that answered your questions and told you a little bit about me.

 

[garbulky]

Garbulky, I can only re-iterate the above. We have told you all we can. The information is verifiable elsewhere. I think we are all a bit a bit of a loss as to what else we can tell you, or help you with. We dont understand your negative attitude to USB.

No problems. I appreciate people's help trying to find my unicorn! The forum members have told me all that I was looking for regarding my question. Maybe it's time has passed and so never shall exist. Now I guess I'm just chit chatting in the thread.
My "negative" attitude to USB is because my approach is subjective. If I don't like it, I don't like it. It's just not something I'm interested in.

 

[Wombat]

No problems. I appreciate people's help trying to find my unicorn! Maybe it's time has passed. Now I guess I'm just chit chatting in the thread.
My negative attitude to USB is because my approach is subjective. If I don't like it, I don't like it. It's just not something I'm interested in.

So be it.

 

[March Audio]

As I've mentioned, I am a subjective person and I recognize that I am in a science forum. I grant that's kind of confusing.

I don't plan on debating why I am not following a more objective way of doing things here. I think that would be bad form. I'm in a science forum after all!

.

Actually no I dont think its confusing, they are not mutually exclusive. We all have subjective opinions, however what is recognised on this forum is the frailty of subjective observation that is performed without controls.

Your current subjective opinion appears to be that usb produces inferior sound. Whilst Im sure you can find defective usb implementations (did someone mention Schitt?) the simple fact is that there is nothing wrong with usb objectively or subjectively. This really can be demonstrated to be the case. Your subjective view has no basis, which is the bit people I think are struggling with.

Some people say they like the sound of record decks, thats fine they do sound different for many objective measureable technical reasons. Properly implemented usb doesnt sound different to properly implemented spdif. This forum ddoesnt indulge in audiophile folkelore, fairy stories or unsubstantiated marketing bs from manufacturers that may claim otherwise.

 

[garbulky]

Actually no I dont think its confusing, they are not mutually exclusive. We all have subjective preferences. However what is recognised on this forum is the frailty of subjective observation that is performed without controls.

Your current subjective opinion appears to be that usb produces inferior sound. Whilst Im sure you can find defective usb implementations (did someone mention Schitt?) the simple fact is that there is nothing wrong with usb objectively or subjectively. This really can be demonstrated to be the case. Your subjective view has no basis, which is the bit people I think are struggling with.

Some people say they like the sound of record decks, thats fine they do sound different for many objective measureable technical reasons. Properly implemented usb doesnt sound different to properly implemented spdif. This forum ddoesnt indulge in audiophile folkelore, fairy stories or unsubstantiated marketing bs from manufacturers.

I got no issue with any of this. I also agree that subjective listening is prone to all kinds of issues.

 

[March Audio]

I got no issue with any of this.

So really I would respectfully suggest you try to look at things a different way. Get someone to assist you with a blind test comparing usb and spdif inputs on your dac. If you can reliably and repeatedly tell the differenc when you dont know which is playing fair enough, but I am confident that wont be the outcome.

 

[garbulky]

So really I would respectfully suggest you try to look at things a different way. Get someone to assist you with a blind test comparing usb and spdif inputs on your dac. If you can reliably and repeatedly tell the differenc when you dont know which is playing fair enough, but I am confident that wont be the outcome.

I haven't done a blind test. But I have done level matched sighted tests. I am certain I would fail a blind test on almost anything to do with electronics. The level matched sighted tests were hard enough that I could barely tell a difference for most of them. Though I did with some.

 

[garbulky]

@BE718
Sorry to add, let's just assume I would fail a blind test. I'll admit that right away.

 

[March Audio]

I haven't done a blind test. But I have done level matched sighted tests. I am certain I would fail a blind test on almost anything to do with electronics. The level matched sighted tests were hard enough that I could barely tell a difference for most of them. Though I did with some.

So why all the angst regarding usb? It would solve your connection issue It might even perform slightly technically better even if that improvement is not audible

 

[garbulky]

So why all the angst regarding usb? It would solve your connection issue It might even perform slightly technically better (even if that improvement is not audible)

There's no angst. It doesn't sound as good to me.

 

[March Audio]

There's no angst. It doesn't sound as good to me.

But you just suggested you can barely tell the difference sighted and are certain you would fail blind.

In other words you have just articulated the sighted test result is not to be trusted. Yet you still have an issue with usb. It seems an unfounded concern in that case. Your conclusion about usb is biased.

 

[garbulky]

But you just suggested you can barely tell the difference sighted and are certain you would fail blind.

In other words you have just articulated the sighted test result is not to be trusted. Yet you still have an issue with usb. It seems an unfounded concern in that case.

You're not wrong here for the most part.
Well, I didn't really want to say this because it is a science forum and I feel like I'm pissing in the cheerios. But I don't make my decisions according to those tests. Also I'm not really concerned about USB.
I feel like we are going around in circles. I'm just repeating the same thing in different ways.

 

[March Audio]

Well, Im going to try and say this respectfully. You acknowledge that sighted comparisons are problematic and that you think you would fail a blind test. A blind comparison is just a subjective comparison with a major source of bias removed. You are still relying on your subjective judgement. You also ignore technical information and the subjective evidence and information others provide that show there is nothing wrong with usb.

Your position is therefore just dogma.

 

[garbulky]

Well, Im going to try and say this respectfully. You acknowledge that sighted comparisons are problematic and that you think you would fail a blind test. A blind comparison is just a subjective comparison with a major source of bias removed. You are still relying on your subjective judgement. You also ignore technical information and the subjective evidence and information others provide that show there is nothing wrong with usb.

Your position is therefore just dogma.

I don't know if that's what this is. I think it's more me going with what I like and want while fully acknowledging that my method is flawed in all kinds of ways.

My method is listening to it over hopefully a long period of time and seeing if I like it. No level matched. No real side by side comparisons. Though I do perform some side to side comparisons and yes sometimes they do come in to my decision making if the differences are really pronounced to the negative. As in well f*** that for a bag of chips type of impression.

Lots of flaws to it. Your ears get "broken in due to time". You forget what you heard before. Auditory memory is very short and therefore can be unreliable. The level's are not matched so loudness can easily be picked over a softer sound. Etc.

Nothing is perfect. But my method still hasn't failed to bring me enjoyment and fulfillment in my audio listening. More importantly it's the one I choose

It seems that you choose DBT listening for decisions. But has there been any DBT tests that show that when listening to regular music - not tones - that there is any audible difference between the mainstream digital audio connections regardless of clocks and jitter performance in normal jitter conditions? Because if there isn't who cares what method I use or what I think doesn't sound good in whatever flawed manner. I'm using BNC right now so it should be identical in audible sound whether I think somethings sounds good or not.

 

[Wombat]

I'm saying I want this.
You're telling me, but no you really want this.
I say I don't like it.

I don't know if that's what this is. I think it's more me going with what I like and want while fully acknowledging that my method is flawed in all kinds of ways.

My method is listening to it over hopefully a long period of time and seeing if I like it. No level matched. No real side by side comparisons. Though I do perform some side to side comparisons and yes sometimes they do come in to my decision making if the differences are really pronounced to the negative. As in well f*** that for a bag of chips type of impression.

Lots of flaws to it. Your ears get "broken in due to time". You forget what you heard before. Auditory memory is very short and therefore can be unreliable. The level's are not matched so loudness can easily be picked over a softer sound. Etc.

Nothing is perfect. But my method still hasn't failed to bring me enjoyment and fulfillment in my audio listening. More importantly it's the one I choose

It seems that you choose DBT listening for decisions. But has there been any DBT tests that show that when listening to regular music that there is any audible difference between digital audio connections? Because if there isn't who cares what method I use or what I think doesn't sound good in whatever flawed manner. I'm using BNC right now so it should be identical in audible sound whether I think somethings sounds good or not.

That is fine as a personal approach. An honest answer.

Others with a similar approach feel a need to add some authority to it by putting forward nonsensical arguments. Accordingly, there will be push-back on this forum.

 

[March Audio]

It seems that you choose DBT listening for decisions. But has there been any DBT tests that show that when listening to regular music - not tones - that there is any audible difference between the mainstream digital audio connections regardless of clocks and jitter performance in normal jitter conditions? Because if there isn't who cares what method I use or what I think doesn't sound good in whatever flawed manner. I'm using BNC right now so it should be identical in audible sound whether I think somethings sounds good or not.

No, Im just aware of the pitfalls of sighted listening which is what you have based your decisions upon. I cant bring you an example right now of a DBT that shows difference between connections - but I'm not sure what that would demonstrate to you if I did. You could simply perform this comparison yourself if you had genuine interest in the result

The point here is you are the one seeking to spend money on a new card because you apparently want "better clocks" - this is a technical improvement, one which you believe will provide a corresponding subjective improvement. However the technical solution to that problem is to use a USB connection which would utilise the DACs internal clock. Yet you dont want this.

So if you want what you want, regardless of any other evidence or advice - "More importantly it's the one I choose " - then yes it very much sounds like dogma. One has to shrug ones shoulders and walk away and leave you to it

 

[Purité Audio]

Ultimately you must listen to what you like, a little technical knowledge is useful in that it at least saves you from the more flagrant BS.
Keith