Understanding USB

[mansr]

10 minutes ago, Speed Racer said:

Because it is not true!

Sure, if by better you mean more expensive.

[GUTB]

39 minutes ago, mansr said:

Sure, if by better you mean more expensive.

 

By better we typically mean sounds better.

 

Even if you don’t want to go through the minor trouble of buying and returning to test your belief system, could you at least make it out an audio show and listen for yourself? Audio shows aren’t the best venues for real listening but some DACs and some rooms are very impressive. Go listen to an Optologic, a Wavedream, Yggdrasil, etc, and come back with your findings. 

[mansr]

7 minutes ago, GUTB said:

Even if you don’t want to go through the minor trouble of buying and returning to test your belief system, could you at least make it out an audio show and listen for yourself? Audio shows aren’t the best venues for real listening but some DACs and some rooms are very impressive. Go listen to an Optologic, a Wavedream, Yggdrasil, etc, and come back with your findings

At a show, it's highly unlikely that they'd be using the same amps and speakers. Any comparisons made there are meaningless.

[unbalanced output]

On 19/10/2017 at 4:40 PM, Fitzcaraldo215 said:

Or, if you do the comparison properly - blind or double blind - you may be surprised that there is no worthwhile difference. 

 

One can obviously spend even more time arguing with naysayers, but it's better to spend time doing something more productive in life. 

[Ralf11]

6 hours ago, unbalanced output said:

 

One can obviously spend even more time arguing with naysayers, but it's better to spend time doing something more productive in life. 

 

it's better to believe than to test

[beerandmusic]

On 10/18/2017 at 7:02 PM, GUTB said:

USB is an awful audio transport medium -- it's just the only option for very high-rez audio. USB was not designed for audio in mind. It's 5v line is very noisy. There is no power quality requirement, no shielding requirement and no manufacturer standard for cable impedance. The el-cheapo USB cables are designed to work reliably up to 5-6 feet, and anything more is out the window. Infested with dirty power, conducting EMI, impedance mis-matching, etc -- who cares. High quality USB cables are at least built to ensure a reliable 90 Ohms, isolation of the 5v line from the data lines, and good shielding against EMI.

 

A robust USB chain however must include some means to filter out noise from getting into the cable to begin with. The use of linear PSUs and various connector filters on the motherboard is one way (I use a PP OCXO USB controller externally powered off a 5v battery). USB conditioners and isolators are another way.

 

1. A linear PSU will generate much lower ripple than even the best low-ripple ATX power supplies. Also, linear PSUs are less likely to cause ground loops.

2. Elimination of electrical noise from the motherboard's power rails through SATA filters, elimination of fans and the like. I just power my SSD externally into a separate power circuit to completely eliminate SSD power noise from ever getting into the audio circuit. Also there is not a single fan anywhere in my audio PC.

3. Tuning of the OS for dedicated audio use -- reduces self-noise generated by the computer running uneeded tasks.

4. Use of an audiophile-grade USB controller either externally powered like mine, or internally powered from a clean source. Audiophile-grade USB controllers have advanced clocks that will ensure a very high quality transmission. A pristine clock edge means less work for the DAC controller.

5. Isolation of USB from the DAC altogether through various methods -- optical bridging, LAN bridging, DDCs, etc.

 

These tactics should go together to form a strategy. It takes time, learning, and some cost, but the gains are large and should not be overlooked. To see immediate gains right away, start with a USB filter / isolator and once you experience the SQ boost and then realize what you thought you knew about digital audio is false you will be emotionally prepared to take the plunge.

 

 

I don't believe ANY of this usb chain stuff is necessary if your dac has optoisolation.  I tend to beieve Mike Moffat over you...it also makes perfect logical sense if you stop and think about it.

 

Maybe this stuff works well for a DAC that isn't designed well to handle noise.

[unbalanced output]

How many DACs with built-in optoisolation are out there? You're probably aware that it's limited to 192/24.

[unbalanced output]

15 hours ago, Ralf11 said:

 

it's better to believe than to test

 

It's better to test than to argue

[GUTB]

48 minutes ago, unbalanced output said:

How many DACs with built-in optoisolation are out there? You're probably aware that it's limited to 192/24.

 

I can't think of a single one.

[sbgk]

a recent and interesting discussion that discusses usb sync vs async from the hardware and software side from a windows driver perspective.

https://www.freelists.org/post/wdmaudiodev/Windows-Clock-Compensation 

just click next by date

[Fitzcaraldo215]

6 hours ago, unbalanced output said:

 

It's better to test than to argue

Agreed.  

 

You have done your tests leading you to your conclusions.  I have done my own comparative testing leading me to conclude the Regen, which you value, does not provide preferable sound into my galvanically isolated DAC.  A friend independently concluded the same thing, as I later found out.  He sold his.  Mine gathers dust, unused.  So, what else is new other than the old YMMV?

[unbalanced output]

12 hours ago, Fitzcaraldo215 said:

Agreed.  

 

You have done your tests leading you to your conclusions.  I have done my own comparative testing leading me to conclude the Regen, which you value, does not provide preferable sound into my galvanically isolated DAC.  A friend independently concluded the same thing, as I later found out.  He sold his.  Mine gathers dust, unused.  So, what else is new other than the old YMMV?

 

Point is, even if it doesn't fit the bill for you, your friend or me, it doesn't mean it doesn't work well in other setups. 

 

18 hours ago, GUTB said:

 

I can't think of a single one.

 

Naim NDS and that's maybe it. 

[GUTB]

14 hours ago, Fitzcaraldo215 said:

Agreed.  

 

You have done your tests leading you to your conclusions.  I have done my own comparative testing leading me to conclude the Regen, which you value, does not provide preferable sound into my galvanically isolated DAC.  A friend independently concluded the same thing, as I later found out.  He sold his.  Mine gathers dust, unused.  So, what else is new other than the old YMMV?

 

Can you describe your audio chain? I’d like to understand why/how you benefit from noise filtration but not from other conditioning of the signal.

[beerandmusic]

On 10/21/2017 at 10:08 AM, unbalanced output said:

How many DACs with built-in optoisolation are out there? You're probably aware that it's limited to 192/24.

 

Yea, and i was a hard cord DSD guy.  I just believe that a "USB" DAC should be designed to compensate for "usb".  Also why i said I would probably never buy another dac unless Schiit or some other DAC manufacturer comes out with a DAC that properly compensates for USB noise, supports DSD, has multiple DAC chips, and is less than $1500, and I can still get $1K for my now used gungnir.

 

[beerandmusic]

On 10/21/2017 at 10:57 AM, GUTB said:

 

I can't think of a single one.

referring to Schiit yggi and gungnir with usb gen5.

Kind of ridiculous in my mind to have to chain toys instead of properly designing a DAC.

I hope others follow suit of managing noise issues without needing a chain of "toys" or stupid cables....surprised it has taken this long.

[hdo]

20 minutes ago, beerandmusic said:

I hope others follow suit of managing noise issues without needing a chain of "toys" or stupid cables....surprised it has taken this long.

 

 It is stupid thing to chain toys between dac and computer usb as they are likely to do harm than do good. USB communication requires good timing. Adding toys in between can do negative effects on timely communication. Indeed, it is stupid to chain useless devices.

[fas42]

20 minutes ago, beerandmusic said:

referring to Schiit yggi and gungnir with usb gen5.

Kind of ridiculous in my mind to have to chain toys instead of properly designing a DAC.

I hope others follow suit of managing noise issues without needing a chain of "toys" or stupid cables....surprised it has taken this long.

 

This is sorta the whole problem with current audio ... systems, which are almost always a hodge podge of boxes and cables, are not "properly designed" - so, "noise issues" are rampant. Why it's taking so long to fix the situation is that, firstly, the people who have the necessary technical skills don't recognise or accept that there is a problem; and secondly, the measuring equipment to put numbers to what's going on are not on every test bench, or the correct methodology for deriving useful data is not known.

[Speed Racer]

56 minutes ago, beerandmusic said:

referring to Schiit yggi and gungnir with usb gen5.

 

Schiit is not using optoisolation. They use a transformer design.

[beerandmusic]

9 hours ago, Speed Racer said:

 

Schiit is not using optoisolation. They use a transformer design.

Ok, I just quoted someone else that said they used optoisolation.  I don't really care what dac designers do, as long as they engineer some solution into the dac so that toys are not needed.  After all they are USB DACs, so they should design them to work with any usb shortcomings....  I am glad that Schiit has, and a few others using galvanic isolation, and I hope any new mid-fi dac or above take same into consideration.  I am sure we are not far off from having quality dsd dacs which engineer noise toys into the dac.  I have been screaming for this for over a couple years now.

 

 

[Fitzcaraldo215]

9 hours ago, beerandmusic said:

Ok, I just quoted someone else that said they used optoisolation.  I don't really care what dac designers do, as long as they engineer some solution into the dac so that toys are not needed.  After all they are USB DACs, so they should design them to work with any usb shortcomings....  I am glad that Schiit has, and a few others using galvanic isolation, and I hope any new mid-fi dac or above take same into consideration.  I am sure we are not far off from having quality dsd dacs which engineer noise toys into the dac.  I have been screaming for this for over a couple years now.

 

 

Galvanic isolation is real, not a toy.  Many external USB gizmos are indeed toys with either no effect or negative effects.  What we want is solid engineering. Some DACS offer that now.  

 

Some do not, but many toys, cables, etc. are of no help.  They may even change the sound, but they do not necessarily make it better.  Some users may be fooled by that.  

[beerandmusic]

37 minutes ago, Fitzcaraldo215 said:

Galvanic isolation is real, not a toy.  Many external USB gizmos are indeed toys with either no effect or negative effects.  What we want is solid engineering. Some DACS offer that now.  

 

Some do not, but many toys, cables, etc. are of no help.  They may even change the sound, but they do not necessarily make it better.  Some users may be fooled by that.  

i coined the phrase "usb toys" as it has been my long time belief that it should be built into the DAC, and have stated so after the first such toys came out.  I am not saying they are toys because they do or do not work....just that it is a contraption thet should be engineered into the dac.

[Speed Racer]

Using "toys" suggest they do nothing useful. Some do. I like the term "decrapifiers"......

[Fitzcaraldo215]

1 minute ago, Speed Racer said:

Using "toys" suggest they do nothing useful. Some do. I like the term "decrapifiers"......

If only that is what they all did with no ill effects.  I do not believe that is always the case.

[Samuel T Cogley]

Currently using an iFI iGalvanic 3.0 with an iDAC2.  My casual, non-blind testing suggests the audio noise floor is lower with the iGalvanic.  Also, quality, but mass market USB3 cables on both ends of the iGalvanic seem to make the biggest difference.  Curiously, the USB3 cable that iFI supplied with the iGalvanic is crap.  After substituting a better cable, issues with the OS complaining about the device drawing too much USB power have discontinued.

[One and a half]

5 minutes ago, Samuel T Cogley said:

Currently using an iFI iGalvanic 3.0 with an iDAC2.  My casual, non-blind testing suggests the audio noise floor is lower with the iGalvanic.  Also, quality, but mass market USB3 cables on both ends of the iGalvanic seem to make the biggest difference.  Curiously, the USB3 cable that iFI supplied with the iGalvanic is crap.  After substituting a better cable, issues with the OS complaining about the device drawing too much USB power have discontinued.

Consider it's possible that during packing, the white ties binds the cable too much in the packaging, breaks or creates a high resistance joint, or worse perhaps in your case, a short to the shield. I haven't experienced any such drama with the stock iGalvanic 3.0 cables, the system works, but cabling does affect the SQ, subjectively.