M
mpw
Guest
if so then why have the USB as an input at all ?
I know its a design and marketing question but still..
regards
I know its a design and marketing question but still..
regards
Dac shootout. Hex vs Vega vs Yggdrasil
- Thread starter prem
- Start date
Because consumers want it as a convenience feature, even if it doesn't sound as good as the no compromise input. For me, the primary format is still CDs but I still wouldn't buy a current gen DAC without a USB input. I may only use it for passive listening but its still a very relevant feature. I am sure there are others in the same boat.
well put. too much effort needed to make digital sound right, sometimes i wonder how much time is wasted in doing this than listening to music in comparison to playing a cd. technology is evolving very quickly and hence when one is buying some high priced electronics, one aspect should be kept in mind with respect to upgradation options available in it or not.
other option is to buy no so expensive gear so that when one upgrades it does not pinch pocket too much, atleast for people having small to medium size pockets.
Hi Prem
This is about the optical.I have tried entry level coaxial vs entry level optical (MX/bluerigger) from my marantz CD player to the metrum , but though the optical had a blacker background (possibly due to the galvanic isolation) the highs sounded harsher than the coaxial.
Now Im in the process of upgrading the cable and am confused between the two.(JPS labs/lifatec). Any suggestions?
cheers
M
mpw
Guest
i agree jai - in part.
Schiit has always stuck its neck out in the market and thumbed its nose at conventional thinking ( or packaging ??
) .By that logic - in their top pf the line DAC - things had better be good including the USB otherwise if customers want to use USB as a convenience feature they are better off with a "normal usb dac " or something,,
so why not be upfront about it ( by a company which claims to be upfront about many things ) and not offer the USB option as at this price level - the customer is looking for good sound as well as convenience ??
regards
square_wave
Well-Known Member
AES/EBU is the professional standard for digital audio according to the audio engineering society. Why is this not standard in audio gear ? Is there some cap of bit rate / resolution?
regeHA
Well-Known Member
There really is no fixing USB with PC as source, at least not from a galvanic isolation point. Its used to power so many external devices like USB hubs, HDDs, pen drives, mobiles, etc.
Jitter is not so much of an issue these days. Galvanic isolation/clean power needs to be addressed at the DAC and not at the source PC or even the USB interface. I really don't see a scenario where USB will be data only and no power... its too much of an industry standard that powers so many external devices, its not going to change.
Anyways other than the high res crowd I don't see USB outperforming Toslink or Coaxial for RBCD content and 99% of folks listen to RBCD or lower resolution like MP3. USB is more of a convenience where everyone has a USB cable, but not necessarily a quality digital cable for audio. Even I started with USB when using external DAC... as I had so many USB cables lying around the house. Once I heard things differently with even budget optical cables like Monoprice there was no going back to USB and then glass optical takes things to an even different level.
Jitter is not so much of an issue these days. Galvanic isolation/clean power needs to be addressed at the DAC and not at the source PC or even the USB interface. I really don't see a scenario where USB will be data only and no power... its too much of an industry standard that powers so many external devices, its not going to change.
Anyways other than the high res crowd I don't see USB outperforming Toslink or Coaxial for RBCD content and 99% of folks listen to RBCD or lower resolution like MP3. USB is more of a convenience where everyone has a USB cable, but not necessarily a quality digital cable for audio. Even I started with USB when using external DAC... as I had so many USB cables lying around the house. Once I heard things differently with even budget optical cables like Monoprice there was no going back to USB and then glass optical takes things to an even different level.
I think we are comparing 2 different topics with different contexts here
USB: Is a means of sending out digital files from a computer to a DAC or streamer (for lack of a better word..it can be a specialized audio computer)
SPDIF/Opt/AES : Is a means of giving a PCM/DSD data as input to a DAC from any Audio device
You can still give a USB input to a streamer and connect that to a dac via SPDIF/Opt
-but if you do not have a streamer then you have no other way other than USB of giving the input to a DAC from a computer,
Of course am only talking in terms of the technology and not in terms of sound quality as based on the components we can use different options to do the same eg -using a converter separately to convert to a SPDIF is the same (in theory) as the USB input of a dac which does the same internally ..although not into SPDif but I2S
BTW not even talking of the computer Sound card which does a spdif output as thats just an inboard converter,
USB: Is a means of sending out digital files from a computer to a DAC or streamer (for lack of a better word..it can be a specialized audio computer)
SPDIF/Opt/AES : Is a means of giving a PCM/DSD data as input to a DAC from any Audio device
You can still give a USB input to a streamer and connect that to a dac via SPDIF/Opt
-but if you do not have a streamer then you have no other way other than USB of giving the input to a DAC from a computer,
Of course am only talking in terms of the technology and not in terms of sound quality as based on the components we can use different options to do the same eg -using a converter separately to convert to a SPDIF is the same (in theory) as the USB input of a dac which does the same internally ..although not into SPDif but I2S
BTW not even talking of the computer Sound card which does a spdif output as thats just an inboard converter,
panditji
Well-Known Member
Rob Watts of Chord does consider the USB input to be the best sounding as Chord DACs have galvanic isolation ... Schiit Audio do not think highly of USB but Chord DACs do sound very good through the USB input....
Panditji, at least from the various threads I have read, I think Rob Watts clearly prefers optical.
This is not to say his USB implementation is not good.
Its not that Schiit is bad. Majority who own Schiit hear it through the USB. Its just that my personal preference is optical
This is not to say his USB implementation is not good.
Its not that Schiit is bad. Majority who own Schiit hear it through the USB. Its just that my personal preference is optical
Below is what Rob Watts has to say
"Yes I have said many times that I prefer optical.
I have not done this listening test for many years - I just use optical always and that's that - I thought I would re-do the listening test. In this case, whilst listening between optical and coaxial, I disconnected the input as well as switched the source button.
Optical was indeed as I listened before - it is noticeably warmer, smoother, with better timbre variations on individual instruments and better instrument separation. Now it also sounds softer, as it is less hard and on a superficial basis is less impressive - the hardness can easily be confused with more detail resolution and impact. But it's a lot more natural.
Now optical gets a lot of bad press - more jitter etc. In the case of Hugo, the jitter levels does not matter, as everything gets re-timed against a low jitter clock, so source jitter is completely removed. Incidentally, the AP test equipment actually measures lower jitter levels on optical than the coaxial inputs, so the jitter story is, in this instance, false.
The benefits of optical is that it isolates the Hugo from the sources' ground injected RF noise. Now anybody reading my posts will say that I am a bit of a timing freak, but I am also a noise floor modulation freak too. RF noise, when it is mixed inside the active analogue electronics, creates inter-modulation distortion which results in the noise floor moving up and down with the analogue signal. I have measured this effect, so I know it is real, and reducing RF noise results in measurable reduction in noise floor modulation. Also I have seen on digital simulation extremely small levels of noise floor modulation, which when removed produces a very audible effect. So the ear/brain is somehow extremely sensitive to this problem.
So how does noise floor modulation account for the observed sound quality changes? Firstly, better instrument separation. Now imagine two instruments playing in a system that has noise floor modulation. You will get noise floor modulation that is a sum of both instruments. Now when the brain has to separate the sounds out, it has now 3 signals to worry about - the two instruments, plus the noise floor modulation which is a combination of both instruments. This confuses the brains processing to be able to tell instruments apart, and hence degrades the brain's perception of the instruments as being separate entities, because you have noise singing along as a combination of the two instruments. This confusion also makes it difficult for the brain, which then will give you listening fatigue.
How does it explain timbre variations? Now imagine listening to one instrument - a saxophone - something rich and smooth sounding. Now noise floor modulation is white noise pumping up and down with the signal level - it has the timbre of hiss, that is very bright sounding. Now add some noise floor modulation, and you are mixing into the sound of the sax something that sounds quite bright. The brain can't tell the difference between the sax, and the noise floor modulation which is proportionate to the sax signal level. So it lumps the timbre together, the rich sound of the sax becomes brighter and less like a sax. We actually end up with all instruments sounding bright, so timbre variations are suppressed.
How does it explain it sounding softer? Well, if you have noise floor modulation, you get more noise with the music peaks, and this often occurs at the initial starting transient - so you get a burst of noise on peak transients, which artificially enhances the sound - it's the MSG of sound quality."
"Yes I have said many times that I prefer optical.
I have not done this listening test for many years - I just use optical always and that's that - I thought I would re-do the listening test. In this case, whilst listening between optical and coaxial, I disconnected the input as well as switched the source button.
Optical was indeed as I listened before - it is noticeably warmer, smoother, with better timbre variations on individual instruments and better instrument separation. Now it also sounds softer, as it is less hard and on a superficial basis is less impressive - the hardness can easily be confused with more detail resolution and impact. But it's a lot more natural.
Now optical gets a lot of bad press - more jitter etc. In the case of Hugo, the jitter levels does not matter, as everything gets re-timed against a low jitter clock, so source jitter is completely removed. Incidentally, the AP test equipment actually measures lower jitter levels on optical than the coaxial inputs, so the jitter story is, in this instance, false.
The benefits of optical is that it isolates the Hugo from the sources' ground injected RF noise. Now anybody reading my posts will say that I am a bit of a timing freak, but I am also a noise floor modulation freak too. RF noise, when it is mixed inside the active analogue electronics, creates inter-modulation distortion which results in the noise floor moving up and down with the analogue signal. I have measured this effect, so I know it is real, and reducing RF noise results in measurable reduction in noise floor modulation. Also I have seen on digital simulation extremely small levels of noise floor modulation, which when removed produces a very audible effect. So the ear/brain is somehow extremely sensitive to this problem.
So how does noise floor modulation account for the observed sound quality changes? Firstly, better instrument separation. Now imagine two instruments playing in a system that has noise floor modulation. You will get noise floor modulation that is a sum of both instruments. Now when the brain has to separate the sounds out, it has now 3 signals to worry about - the two instruments, plus the noise floor modulation which is a combination of both instruments. This confuses the brains processing to be able to tell instruments apart, and hence degrades the brain's perception of the instruments as being separate entities, because you have noise singing along as a combination of the two instruments. This confusion also makes it difficult for the brain, which then will give you listening fatigue.
How does it explain timbre variations? Now imagine listening to one instrument - a saxophone - something rich and smooth sounding. Now noise floor modulation is white noise pumping up and down with the signal level - it has the timbre of hiss, that is very bright sounding. Now add some noise floor modulation, and you are mixing into the sound of the sax something that sounds quite bright. The brain can't tell the difference between the sax, and the noise floor modulation which is proportionate to the sax signal level. So it lumps the timbre together, the rich sound of the sax becomes brighter and less like a sax. We actually end up with all instruments sounding bright, so timbre variations are suppressed.
How does it explain it sounding softer? Well, if you have noise floor modulation, you get more noise with the music peaks, and this often occurs at the initial starting transient - so you get a burst of noise on peak transients, which artificially enhances the sound - it's the MSG of sound quality."
regeHA
Well-Known Member
This only highlights the problem with computer based audio solutions. Having both, a PC and a streamer seems like a moot point.
Unless the goal is DSD or using software like HQP for DSD, a PC is better left out of the equation. Most devices like Aurender and Auralic will outperform the PC even with USB, and they also perform the duties of source, transport and streamer in a single unit.
I'm myself using a NAS and Pi, but these days most of my listening is via CCA on Tidal. At $20 per month and having a catalog of nearly 25 million songs in lossless quality, it hands down beats everything else. Even conservatively it will take a long time for the $20 per month to cover the cost of any source/transport and the purchase of audio CDs and/or music downloads.
Here's another quote from Rob Watts
"To eliminate the RF and signal correlated noise on USB you need galvanic isolation. The downside to galvanic isolation is that it draws power from the source - which is not something we can do with a mobile product. All Chord desktop DAC's have USB galvanic isolation now.
That said, mobile sources are much lower noise - they have very efficient processors, unlike a PC, and there is no ground, so circulating currents are much less, so it is a much smaller problem with mobile. If you can do it, use the optical, as this usually sounds the best and is completely isolated. Optical has a undeservedly poor reputation, as it sounds much smoother and darker than other inputs, and this is just a feature of lower noise floor modulation - its smoother with better instrument separation and focus - but lack of glare is often confused with a lack of detail resolution. Listening tests must be done with a lot of care, as it is easy to draw the wrong conclusions!"
"To eliminate the RF and signal correlated noise on USB you need galvanic isolation. The downside to galvanic isolation is that it draws power from the source - which is not something we can do with a mobile product. All Chord desktop DAC's have USB galvanic isolation now.
That said, mobile sources are much lower noise - they have very efficient processors, unlike a PC, and there is no ground, so circulating currents are much less, so it is a much smaller problem with mobile. If you can do it, use the optical, as this usually sounds the best and is completely isolated. Optical has a undeservedly poor reputation, as it sounds much smoother and darker than other inputs, and this is just a feature of lower noise floor modulation - its smoother with better instrument separation and focus - but lack of glare is often confused with a lack of detail resolution. Listening tests must be done with a lot of care, as it is easy to draw the wrong conclusions!"
true..just wanted to bring out the point the USB is basically for the Output from a PC
i myself use an aries mini. i have both the lifatec glass and the ASI coax after several A/Bs the ASI is more resolving with better separation but the Lifatec is more organic
I dont use the PC either as managing the PC and optimising it is a real Chore.
panditji
Well-Known Member
My apologies Prem, got confused with somebody else's opinion on the CHord USB input....
Hi panditji, no apologies needed please. We are all trying to learn here.
I particularly like the way Rob explains why he prefers the optical and how one can easily get carried away by the other more impressive sounding digital inputs
I particularly like the way Rob explains why he prefers the optical and how one can easily get carried away by the other more impressive sounding digital inputs
Hi Prem: I guess what you excerpted is from Hugo pages on Head-fi while on the 2qute pages (pg 34), here is what Rob has to say:
"Indeed.On 2 Qute the galvanically isolated USB does sound slightly better than Toslink, but it is very small difference.
Rob"
So I guess we are probably equally fine using either of this, atleast for 2qute.:thumbsup:
"Indeed.On 2 Qute the galvanically isolated USB does sound slightly better than Toslink, but it is very small difference.
Rob"
So I guess we are probably equally fine using either of this, atleast for 2qute.:thumbsup:
Kvm, I haven't seen that. Thanks for the update.
I just saw that thread. It's in year 2015. The second quote I have linked to in the thread is from 2016. So maybe he feels optical is still better because in the second link he clearly talks about galvanic ally isolated USB
Anyways I guess it's not a big deal.
I just saw that thread. It's in year 2015. The second quote I have linked to in the thread is from 2016. So maybe he feels optical is still better because in the second link he clearly talks about galvanic ally isolated USB
Anyways I guess it's not a big deal.
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i agree jai - in part.
Schiit has always stuck its neck out in the market and thumbed its nose at conventional thinking ( or packaging ??
By that logic - in their top pf the line DAC - things had better be good including the USB otherwise if customers want to use USB as a convenience feature they are better off with a "normal usb dac " or something,,
so why not be upfront about it ( by a company which claims to be upfront about many things ) and not offer the USB option as at this price level - the customer is looking for good sound as well as convenience ??
regards
There is a difference between not good and not the best solution. I'm assuming that the USB input, while not sounding as good as the ideal input, doesn't sound outright bad. As long as they are not claiming that the USB is as good as it gets (as some manufacturers do), I don't see a problem with having a USB input that isn't as good as the others. Speaking as a consumer, I would rather have a "not as good" USB input on a DAC I like than buying a second, USB only DAC.
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