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What is wrong with usb connection ?


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Hi !

sorry for the uneducated question, but i really wonder what is wrong with usb connection for audio purpose.

I see that an effective usb link between pc and usb dac needs isolators, reclockers, regenerators, filters ... it seems to me that usb standard is at least not optimum for the purpose.

For instance ... i have read that one nice feature of usb solution is that allows for asynchronous data transfer.

And then i hear that usb links are affected by jitter issue ?

I have seen people using even 8-9 devices in series to connect the pc to an usb audio dac

Is all this perfectly acceptable ?

Is there any chance that for instance Thunderbolt is a better option ? or Ethernet ?

Thanks a lot for any advice.

Regards, gino

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I have not found much wrong with it. These devices prey upon FUD in my opinion.

And always keep in mind: Cognitive biases, like seeing optical illusions are a sign of a normally functioning brain. We all have them, it’s nothing to be ashamed about, but it is something that affects our objective evaluation of reality. 

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I have not found much wrong with it. These devices prey upon FUD in my opinion

 

Hi and thank for the reply.

Still their success cannot be based only on bad sensations.

I look at the systems ... they are usually very very resolving. Differences in sound can be spotted quite easily.

I tend to think that noise from the PC can be an issue like any other interference.

And also that a cable can create jitter issues.

I wonder if any other kind of connection could be preferrable.

Thanks again, gino

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Intona Industrial fixes most USB issues, it's a great solution as it makes a very noticeable improvement in my and many others systems. If there is only one box to get then Intona gets my vote.

 

There is also this box coming out soon that looks quite interesting : 2016 Singxer SU-1 USB digital interface with XMOS XU208 CPLD DSD256 DOP - Professional Audio Store - Shenzhenaudio.com

Source:

*Aurender N100 (no internal disk : LAN optically isolated via FMC with *LPS) > DIY 5cm USB link (5v rail removed / ground lift switch - split for *LPS) > Intona Industrial (injected *LPS / internally shielded with copper tape) > DIY 5cm USB link (5v rail removed / ground lift switch) > W4S Recovery (*LPS) > DIY 2cm USB adaptor (5v rail removed / ground lift switch) > *Auralic VEGA (EXACT : balanced)

 

Control:

*Jeff Rowland CAPRI S2 (balanced)

 

Playback:

2 x Revel B15a subs (balanced) > ATC SCM 50 ASL (balanced - 80Hz HPF from subs)

 

Misc:

*Via Power Inspired AG1500 AC Regenerator

LPS: 3 x Swagman Lab Audiophile Signature Edition (W4S, Intona & FMC)

Storage: QNAP TS-253Pro 2x 3Tb, 8Gb RAM

Cables: DIY heavy gauge solid silver (balanced)

Mains: dedicated distribution board with 5 x 2 socket ring mains, all mains cables: Mark Grant Black Series DSP 2.5 Dual Screen

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Galvanic isolation is the only thing that needs to be fixed, and this is based on personal experience. Practically elevated my system to another level with the reduction in noise floor.

 

Jitter is pretty much non-existent today, that's definitely FUD.

Next to the Word of God, the noble art of music is the greatest treasure in the world - Martin Luther

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Well lots of suggestions about jitter. Not much measured improvement. The asynchronous USB usually provides for some amount of buffering. Data is transferred and then a local clock provides clocking. USB isn't like SPDIF where the clocking is embedded within the data stream. The idea jitter can be altered comes from thinking the local clock can have jitter caused by noise and noise can travel over USB from the PC. While noise can do this various methods of isolation minimize this effect on better designed devices.

 

One also should realize jitter as an audible issue in hugely overblown. Most of it is imagination. Take a look at my thread about 16 times jitter being audible. Sound samples there were played over a USB DAC and recorded by USB ADC. Then repeated 8 times. Jitter and noise would be building up higher with each pass thru. Yet I think you will find sound quality was far from destroyed. The original file is there for comparison.

And always keep in mind: Cognitive biases, like seeing optical illusions are a sign of a normally functioning brain. We all have them, it’s nothing to be ashamed about, but it is something that affects our objective evaluation of reality. 

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I have not found much wrong with it. These devices prey upon FUD in my opinion.

 

This statement is a minority on this site, to be blunt and fails to deliver. Then again jitter reduction is for the imagination like this?

 

Jitter reduction Panasonic SV-3700.jpg

 

Your comeback will be oh, this is for S/PDIF output so doesn't apply since we're talking about USB. Hello, it's the same instrument that accepts USB, so you'd think the manufacturer would bypass this jitter reduction technique for USB cause it's FUD?

AS Profile Equipment List        Say NO to MQA

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Intona Industrial fixes most USB issues, it's a great solution as it makes a very noticeable improvement in my and many others systems. If there is only one box to get then Intona gets my vote

 

Hi thanks for the helpful advice. A galvanic isolator if i understand well.

This is indeed what i am trying to understand. Which is the main issue with usb connection.

 

 

very beautiful. But it could be that the Intona is still necessary for best performance.

I do not think that this interface provides also galvanic isolation.

I have already some usb to spdif converters to try. However i miss a serious isolator like the Intona.

I would prefer a version that gives the possibility to inject clean 5VDC downstream the isolator. Some of the above mentioned converters need 5VDC on the usb port to function.

But it is important to me establish that galvanic isolation is a must.

Now the problem could be the added jitter caused by the isolator.

Thanks again, gino

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Galvanic isolation is the only thing that needs to be fixed, and this is based on personal experience. Practically elevated my system to another level with the reduction in noise floor.

Jitter is pretty much non-existent today, that's definitely FUD

 

Thanks a lot indeed. I see a broad agreement on this subject. I will start studying devices like the Intona from what i understand one of the best isolator around.

Kind regards, gino

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Well lots of suggestions about jitter. Not much measured improvement. The asynchronous USB usually provides for some amount of buffering. Data is transferred and then a local clock provides clocking. USB isn't like SPDIF where the clocking is embedded within the data stream. The idea jitter can be altered comes from thinking the local clock can have jitter caused by noise and noise can travel over USB from the PC. While noise can do this various methods of isolation minimize this effect on better designed devices. One also should realize jitter as an audible issue in hugely overblown. Most of it is imagination.

 

Hi and thanks for the very valuable input. Given that we have established the importance of a good galvanic isolation, jitter comes after that. And i am trying to understand the entity of the issue.

 

Take a look at my thread about 16 times jitter being audible. Sound samples there were played over a USB DAC and recorded by USB ADC. Then repeated 8 times. Jitter and noise would be building up higher with each pass thru.

Yet I think you will find sound quality was far from destroyed. The original file is there for comparison

 

i will look for it for sure. Yes this should be the acid test. Jitter is a mistery to me. Never understood completely.

I also read that some high jitter signals can sound nice ?

Thanks a lot again, gino

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This statement is a minority on this site, to be blunt and fails to deliver.

Then again jitter reduction is for the imagination like this?

 

[ATTACH=CONFIG]25812[/ATTACH]

 

Your comeback will be oh, this is for S/PDIF output so doesn't apply since we're talking about USB.

Hello, it's the same instrument that accepts USB, so you'd think the manufacturer would bypass this jitter reduction technique for USB cause it's FUD?

 

Hi and thanks a lot for the very interesting graphs. Really impressive.

I have a question about the picture.

If i understand well the chain in the 1st case is SV-3700 > dac

In the 2nd case is SV-3700 > MC-3+USB > dac

I guess that the connection used is AES/EBU ?

This MC-3 is doing a great job indeed.

 

MUTEC - Professional A/V and High-End Equipment - MC-3+ USB

 

Beutiful unit. I wonder if it provides also galvanic isolation from the pc.

Thanks a lot again, gino

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I have not found much wrong with it. These devices prey upon FUD in my opinion.

 

Amazing isn't it?.....a protocol that works for millions transferring trillions of bits reliably and accurately for both residential and commercial users......yet not suitable for audiophiles on its own!

 

.........and they wonder why the gene pool gets smaller every year!

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This statement is a minority on this site, to be blunt and fails to deliver. Then again jitter reduction is for the imagination like this?

 

[ATTACH=CONFIG]25812[/ATTACH]

 

Your comeback will be oh, this is for S/PDIF output so doesn't apply since we're talking about USB. Hello, it's the same instrument that accepts USB, so you'd think the manufacturer would bypass this jitter reduction technique for USB cause it's FUD?

Thanks for speaking on my behalf, but I prefer to do that. I would say you show what is labeled as a high jitter source. You then put a reclocker and show less jitter. While the device has USB on the title USB isn't being used here. So your point was? Yes their are high jitter devices though very few probably less than two percent have jitter as high as your example. That would include the phone I am sending this upon. Usually even inexpensive DACs will have jitter closer to the 2nd graph just by simply plugging in a direct USB cable.

And always keep in mind: Cognitive biases, like seeing optical illusions are a sign of a normally functioning brain. We all have them, it’s nothing to be ashamed about, but it is something that affects our objective evaluation of reality. 

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Thanks a lot indeed. I see a broad agreement on this subject. I will start studying devices like the Intona from what i understand one of the best isolator around.

Kind regards, gino

 

The USB cable carries both data and power. Plug in your smartphone via USB to the PC and it starts charging. If you can cut open the USB cable and cut out the strand that carries power, you'll have a USB cable that carries only data. That's exactly what the tools achieve to do.

 

I went from a PC to a Raspberry Pi to wireless streaming from the Pi and achieved a huge sonic upgrade. Since then I've moved my media to a NAS that's located in a different room and the content itself is streamed wirelessly to a number of endpoints.

 

Many ways to skin this cat, if you have the DIY chops you can "surgically" enhance your USB cable. I'm squarely lacking in such skills. That leaves the option of tools like USB Regen and Intona USB Isolator and higher up the $$$ chain the Berkeley Alpha USB.

 

In terms of SQ you will achieve lower noise floor - think of it as electrical hum that's not heard, but still discolors the sound. Benefits with lowered noise floor will range from more detail and dynamics to darker blacks.

 

Of course most modern equipment should address this out of the box, and most audio products indeed do, but PCs are not built to isolate electrical noise, hence the noise comes as part of the package when using computers as a source, especially USB. Using something like Toslink does not carry electrical noise, that takes care of things to a great extent.

 

Jitter was a major concern a while back... but most modern devices address it and its not an issue with modern gadgets - at least I've not "seen" or "heard" it, but then audiophiles as a norm are always looking to tweak and/or improve something and hence its a lot easier to sell them black gold.

 

Just my 2 cents...

Next to the Word of God, the noble art of music is the greatest treasure in the world - Martin Luther

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Amazing isn't it?.....a protocol that works for millions transferring trillions of bits reliably and accurately for both residential and commercial users......yet not suitable for audiophiles on its own!

 

.........and they wonder why the gene pool gets smaller every year!

 

I suspect that Gordon Rankin and others, including the guy that designed the original Benchmark DAC know a wee bit more than both of you ! Why did they go to all that trouble with the Benchmark DAC (your DAC perhaps?) if USB had no problems ? The original claim was that it eliminated Jitter. Yes, I heard one not long after it was released and it was nothing special either.

By today's standards it's quite mediocre.

 

How a Digital Audio file sounds, or a Digital Video file looks, is governed to a large extent by the Power Supply area. All that Identical Checksums gives is the possibility of REGENERATING the file to close to that of the original file.

PROFILE UPDATED 13-11-2020

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sorry for the uneducated question, but i really wonder what is wrong with usb connection for audio purpose.

 

There's nothing uneducated about asking a good question!

 

I see that an effective usb link between pc and usb dac needs isolators, reclockers, regenerators, filters ... it seems to me that usb standard is at least not optimum for the purpose.

For instance ... i have read that one nice feature of usb solution is that allows for asynchronous data transfer.

And then i hear that usb links are affected by jitter issue ?

 

There are so many wrong answers in this thread already... You should get a much better answer from someone like John Swenson, but here's my very summarised take on it:

 

You can see here by your own observations something which is inherent to USB: it initially was built for data transfer, and not real-time audio playback. Some people still think that since USB can transfer data reliably, then there cannot be any issue in a real-time audiophile setup. This isn't the case (there is no data re-send in the real-time audiophile use case).

 

Now, a great enhancement was made by Gordon Rankin when he worked on the asynchronous protocol so that the DAC instead of the computer becomes the clock source.

 

While this is great for adapting USB To audiophile purposes, the usual cable is a weak point, as well as the power and ground lines, if the DAC is not totally and perfectly isolated from such issues (most are not but some DAC designers have started working hard on this problem and releasing well-designed DACs which appear to be impervious to these issues, also this is where the add-on devices have found a market).

 

The USB signal although 'digital' usually travels on a normal USB cable as a purely analogue signal with voltage levels as well as ramp up and down times. This means that during transfer in the usual cable, this signal is subject to signal integrity issues (you have a few alternatives here: use the add-on devices, find an extremely well-implemented DAC, use a digital USB Cable (Corning Optical), use very short analogue USB cables or better made ones or use hard USB-USB connectors, use alternate computer->DAC connections like Ethernet or Ethernet + Optic Fibre).

 

Now, to determine the actual bit values at the USB receiving end, this requires extra processing at the interface sub-system, thus requiring bursts of power/current. This extra processing to deal with signal integrity issues can create noise near the DAC chip, affecting its D/A conversion and hence SQ.

 

This is where these new add-on devices can be helpful: some enable a regeneration of the signal before the DAC chip, and/or a re-clocking. Some devices also break the power and ground lines from the computer, thus providing the DAC from isolation from the noisy server and clean power to the DAC. What the Regen does additionally is also optimise/lower the noise profile of its own signal integrity circuits

 

One could also mention issues with noise re-injected into the mains by equipment power supplies (you'll see why in the next point), as well as EMI/RFI internally and in the air. Here, we know that SMPS can cause a lot of direct and indirect damage to SQ and hence people have found it beneficial to replace SMPS by Linear PSUs.

 

I have seen people using even 8-9 devices in series to connect the pc to an usb audio dac

Is all this perfectly acceptable ?

 

The thing is, how much more noise are we introducing with so many devices in a chain? What is our overall cost when we get all these devices, interconnects, new linear power supplies and how does that overall cost compare to a new, better isolated DAC? Personally, I think 8 or 9 devices is way too many devices: I'd rather simplify the chain.

 

It makes much more sense IMO to wait for the devices to become integrated in new DACs or explore alternatives like Ethernet renderers and Ethernet input DACs. Alternately, with DIY, we could build or own by putting our DAC circuit with a Regenerator/Reclocker and clean power in the same chassis and perhaps use a Corning Optical (or else add some additional circuits for the Ethernet route, either doing Ethernet to USB within that chassis on a very short connection (hardware connector ideally) or bypass the USB portion altogether if the DAC circuit allows.

 

Is there any chance that for instance Thunderbolt is a better option ? or Ethernet ?

 

Ethernet has the advantage of already having little isolation transformers at each end in the jacks, so that's one good thing. However, even Ethernet has its own noise profile, so that some have found better results with intermediate conversions with Optic Fibre (see jabbr's thread on network isolation).

 

All this shows that USB is still being adapted to audiophile purposes as we speak.

 

If this weren't the case, all existing DACs would be totally impervious to these issues.

Dedicated Line DSD/DXD | Audirvana+ | iFi iDSD Nano | SET Tube Amp | Totem Mites

Surround: VLC | M-Audio FastTrack Pro | Mac Opt | Panasonic SA-HE100 | Logitech Z623

DIY: SET Tube Amp | Low-Noise Linear Regulated Power Supply | USB, Power, Speaker Cables | Speaker Stands | Acoustic Panels

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The USB cable carries both data and power. Plug in your smartphone via USB to the PC and it starts charging. If you can cut open the USB cable and cut out the strand that carries power, you'll have a USB cable that carries only data. That's exactly what the tools achieve to do.

 

Hi and thanks a lot for the kind and very helpful information.

I forgot to check if the outer shell of the connectors are connected together, i guess trhough the shield.

Also the shield must be cut for complete isolation ?

 

I went from a PC to a Raspberry Pi to wireless streaming from the Pi and achieved a huge sonic upgrade. Since then I've moved my media to a NAS that's located in a different room and the content itself is streamed wirelessly to a number of endpoints.

 

this is very interesting and i wonder if wireless streaming could give a better sound that a usb cable connection.

I know it sounds weird but still ...

 

Many ways to skin this cat, if you have the DIY chops you can "surgically" enhance your USB cable. I'm squarely lacking in such skills. That leaves the option of tools like USB Regen and Intona USB Isolator and higher up the $$$ chain the Berkeley Alpha USB.

In terms of SQ you will achieve lower noise floor - think of it as electrical hum that's not heard, but still discolors the sound. Benefits with lowered noise floor will range from more detail and dynamics to darker blacks.

Of course most modern equipment should address this out of the box, and most audio products indeed do, but PCs are not built to isolate electrical noise, hence the noise comes as part of the package when using computers as a source, especially USB. Using something like Toslink does not carry electrical noise, that takes care of things to a great extent.

Jitter was a major concern a while back... but most modern devices address it and its not an issue with modern gadgets - at least I've not "seen" or "heard" it, but then audiophiles as a norm are always looking to tweak and/or improve something and hence its a lot easier to sell them black gold.

Just my 2 cents...

 

thanks a lot again for the very interesting adivce. Toslink would be indeed an effective barrier against noise and disturbs.

But i read that the quality of toslink port is usually very poor and affected by jitter.

That would be a very nice solution to achieve galvanic isolation (actually i heard many times of optocouplers used in isolators),

I will study the option anyway

Thanks a lot, gino

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this is very interesting and i wonder if wireless streaming could give a better sound that a usb cable connection.

 

Wireless can be very noisy compared to a wired connection like Ethernet.

Dedicated Line DSD/DXD | Audirvana+ | iFi iDSD Nano | SET Tube Amp | Totem Mites

Surround: VLC | M-Audio FastTrack Pro | Mac Opt | Panasonic SA-HE100 | Logitech Z623

DIY: SET Tube Amp | Low-Noise Linear Regulated Power Supply | USB, Power, Speaker Cables | Speaker Stands | Acoustic Panels

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The only advice I can give about the quality of USB is to listen to it. Don't try to listen for faults. Just listen. If any possible faults lie in the protocol or the cable but they don't make themselves apparent enough through casual or semi-focused listening, it's not a big enough deal to waste the time, money and energy trying to fix.

If I am anything, I am a music lover and a pragmatist.

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There's nothing uneducated about asking a good question!

 

 

 

There are so many wrong answers in this thread already... You should get a much better answer from someone like John Swenson, but here's my very summarised take on it:

 

You can see here by your own observations something which is inherent to USB: it initially was built for data transfer, and not real-time audio playback. Some people still think that since USB can transfer data reliably, then there cannot be any issue in a real-time audiophile setup. This isn't the case (there is no data re-send in the real-time audiophile use case).

 

Now, a great enhancement was made by Gordon Rankin when he worked on the asynchronous protocol so that the DAC instead of the computer becomes the clock source.

 

While this is great for adapting USB To audiophile purposes, the usual cable is a weak point, as well as the power and ground lines, if the DAC is not totally and perfectly isolated from such issues (most are not but some DAC designers have started working hard on this problem and releasing well-designed DACs which appear to be impervious to these issues, also this is where the add-on devices have found a market).

 

The USB signal although 'digital' usually travels on a normal USB cable as a purely analogue signal with voltage levels as well as ramp up and down times. This means that during transfer in the usual cable, this signal is subject to signal integrity issues (you have a few alternatives here: use the add-on devices, find an extremely well-implemented DAC, use a digital USB Cable (Corning Optical), use very short analogue USB cables or better made ones or use hard USB-USB connectors, use alternate computer->DAC connections like Ethernet or Ethernet + Optic Fibre).

 

Now, to determine the actual bit values at the USB receiving end, this requires extra processing at the interface sub-system, thus requiring bursts of power/current. This extra processing to deal with signal integrity issues can create noise near the DAC chip, affecting its D/A conversion and hence SQ.

 

This is where these new add-on devices can be helpful: some enable a regeneration of the signal before the DAC chip, and/or a re-clocking. Some devices also break the power and ground lines from the computer, thus providing the DAC from isolation from the noisy server and clean power to the DAC. What the Regen does additionally is also optimise/lower the noise profile of its own signal integrity circuits

 

One could also mention issues with noise re-injected into the mains by equipment power supplies (you'll see why in the next point), as well as EMI/RFI internally and in the air. Here, we know that SMPS can cause a lot of direct and indirect damage to SQ and hence people have found it beneficial to replace SMPS by Linear PSUs.

 

 

 

The thing is, how much more noise are we introducing with so many devices in a chain? What is our overall cost when we get all these devices, interconnects, new linear power supplies and how does that overall cost compare to a new, better isolated DAC? Personally, I think 8 or 9 devices is way too many devices: I'd rather simplify the chain.

 

It makes much more sense IMO to wait for the devices to become integrated in new DACs or explore alternatives like Ethernet renderers and Ethernet input DACs. Alternately, with DIY, we could build or own by putting our DAC circuit with a Regenerator/Reclocker and clean power in the same chassis and perhaps use a Corning Optical (or else add some additional circuits for the Ethernet route, either doing Ethernet to USB within that chassis on a very short connection (hardware connector ideally) or bypass the USB portion altogether if the DAC circuit allows.

 

 

 

Ethernet has the advantage of already having little isolation transformers at each end in the jacks, so that's one good thing. However, even Ethernet has its own noise profile, so that some have found better results with intermediate conversions with Optic Fibre (see jabbr's thread on network isolation).

 

All this shows that USB is still being adapted to audiophile purposes as we speak.

 

If this weren't the case, all existing DACs would be totally impervious to these issues.

 

+1 Very well explained :) Thanks !

Alain

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Hi and thanks a lot for the kind and very helpful information.

I forgot to check if the outer shell of the connectors are connected together, i guess trhough the shield.

Also the shield must be cut for complete isolation ?

 

Ah, like I said I'm squarely lacking in any DIY or surgical skills. Wouldn't even know where to begin... so I'd simply buy the solution.

 

this is very interesting and i wonder if wireless streaming could give a better sound that a usb cable connection.

I know it sounds weird but still ...

 

In my case it did. May not do if for you.

 

That's why I recommend folks test it for themselves with a $35 Raspberry Pi. It's cheap and takes less than 20 mins to set it up. If it works for you then go ahead and get a $600 NAS + HDDs, if it doesn't you have not lost much in the way of $35, and you can always repurpose it for Kodi, VPN server, etc.

 

For me it did so I went a NAS, and a gigabit wireless AC network. It's been the best upgrade for me and just north of $1000 has been money well spent in terms of improvement in SQ. It raised the bar on my existing equipment so much so that I'm really digging in and enjoying all of my music again.

 

thanks a lot again for the very interesting adivce. Toslink would be indeed an effective barrier against noise and disturbs.

But i read that the quality of toslink port is usually very poor and affected by jitter.

That would be a very nice solution to achieve galvanic isolation (actually i heard many times of optocouplers used in isolators),

I will study the option anyway

Thanks a lot, gino

 

I use wireless and then Toslink to DAC. For me it beats both USB and coaxial and I like to think of it as achieving galvanic isolation x 2 i.e. at both ends with wireless and then Toslink (again light for data).

 

It may not work for everyone, but it did for a couple of friends who tried with the Pi and after seeing DLNA beats USB, HDMI, etc. are now going the route of a NAS.

 

MinimServer is the popular choice here... so keep that in mind if you ever decide to give it a try with the Raspberry Pi for yourself.

Next to the Word of God, the noble art of music is the greatest treasure in the world - Martin Luther

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There's nothing uneducated about asking a good question!

There are so many wrong answers in this thread already...

You should get a much better answer from someone like John Swenson, but here's my very summarised take on it:

You can see here by your own observations something which is inherent to USB: it initially was built for data transfer, and not real-time audio playback. Some people still think that since USB can transfer data reliably, then there cannot be any issue in a real-time audiophile setup.

This isn't the case (there is no data re-send in the real-time audiophile use case).

Now, a great enhancement was made by Gordon Rankin when he worked on the asynchronous protocol so that the DAC instead of the computer becomes the clock source.

While this is great for adapting USB To audiophile purposes, the usual cable is a weak point, as well as the power and ground lines, if the DAC is not totally and perfectly isolated from such issues (most are not but some DAC designers have started working hard on this problem and releasing well-designed DACs which appear to be impervious to these issues, also this is where the add-on devices have found a market).

The USB signal although 'digital' usually travels on a normal USB cable as a purely analogue signal with voltage levels as well as ramp up and down times. This means that during transfer in the usual cable, this signal is subject to signal integrity issues (you have a few alternatives here: use the add-on devices, find an extremely well-implemented DAC, use a digital USB Cable (Corning Optical), use very short analogue USB cables or better made ones or use hard USB-USB connectors, use alternate computer->DAC connections like Ethernet or Ethernet + Optic Fibre).

Now, to determine the actual bit values at the USB receiving end, this requires extra processing at the interface sub-system, thus requiring bursts of power/current. This extra processing to deal with signal integrity issues can create noise near the DAC chip, affecting its D/A conversion and hence SQ.

This is where these new add-on devices can be helpful: some enable a regeneration of the signal before the DAC chip, and/or a re-clocking.

Some devices also break the power and ground lines from the computer, thus providing the DAC from isolation from the noisy server and clean power to the DAC. What the Regen does additionally is also optimise/lower the noise profile of its own signal integrity circuits

One could also mention issues with noise re-injected into the mains by equipment power supplies (you'll see why in the next point), as well as EMI/RFI internally and in the air. Here, we know that SMPS can cause a lot of direct and indirect damage to SQ and hence people have found it beneficial to replace SMPS by Linear PSUs.

The thing is, how much more noise are we introducing with so many devices in a chain? What is our overall cost when we get all these devices, interconnects, new linear power supplies and how does that overall cost compare to a new, better isolated DAC?

Personally, I think 8 or 9 devices is way too many devices: I'd rather simplify the chain.

It makes much more sense IMO to wait for the devices to become integrated in new DACs or explore alternatives like Ethernet renderers and Ethernet input DACs. Alternately, with DIY, we could build or own by putting our DAC circuit with a Regenerator/Reclocker and clean power in the same chassis and perhaps use a Corning Optical (or else add some additional circuits for the Ethernet route, either doing Ethernet to USB within that chassis on a very short connection (hardware connector ideally) or bypass the USB portion altogether if the DAC circuit allows.

Ethernet has the advantage of already having little isolation transformers at each end in the jacks, so that's one good thing. However, even Ethernet has its own noise profile, so that some have found better results with intermediate conversions with Optic Fibre (see jabbr's thread on network isolation).

All this shows that USB is still being adapted to audiophile purposes as we speak.

If this weren't the case, all existing DACs would be totally impervious to these issues

 

Hi ! thanks a lot for the very kind and valuable explanation.

i start to understand better the challenge of building a very good usb connection for audio peripherals.

What i do not understand is why so few dacs provide isolation, given that isolation is an almost mandatory requirement.

And then there is the added jitter.

I will study better your answer but i have already now a question about Ethernet.

 

Yesterday i connected a usb dac/headphone amp to the pc through an usb extender on rj45 Ethernet cable.

It consists in two boxes:

- one sender to be connected to the pc with a usb cable

- one receiver that has usb ports and a dc socket for a power supply.

In the between the rj45 cable (flat type / 3 meters).

The sender is using usb bus power while the receiver has its own 5VDC smps.

I swear the sound in the headphone was better.

Less noise and more details.

Am i hearing things ?

Is it possible that this extender actually blocks some electric garbage coming from the pc ?

or can it have some positive effects keeping the jitter low ?

Thanks a lot again, gino

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Ah, like I said I'm squarely lacking in any DIY or surgical skills.

Wouldn't even know where to begin... so I'd simply buy the solution.

In my case it did. May not do if for you.

That's why I recommend folks test it for themselves with a $35 Raspberry Pi. It's cheap and takes less than 20 mins to set it up. If it works for you then go ahead and get a $600 NAS + HDDs, if it doesn't you have not lost much in the way of $35, and you can always repurpose it for Kodi, VPN server, etc.

 

Hi again ! i am a little scared of OS other than win 7 ... i am not very expert with pc.

I have always used win 7 as OS and found it quite ok all considered and usually drivers are available for win 7.

 

For me it did so I went a NAS, and a gigabit wireless AC network. It's been the best upgrade for me and just north of $1000 has been money well spent in terms of improvement in SQ. It raised the bar on my existing equipment so much so that I'm really digging in and enjoying all of my music again

 

i have already a little NAS that i use with positive results. I like the idea of having a storage with all my cds loaded in.

 

I use wireless and then Toslink to DAC

 

sorry ... do you mean that you go from the Raspberry to the Dac with toslink ? sorry if i had missed it.

 

For me it beats both USB and coaxial and I like to think of it as achieving galvanic isolation x 2 i.e. at both ends with wireless and then Toslink (again light for data). It may not work for everyone, but it did for a couple of friends who tried with the Pi and after seeing DLNA beats USB, HDMI, etc. are now going the route of a NAS.

MinimServer is the popular choice here... so keep that in mind if you ever decide to give it a try with the Raspberry Pi for yourself.

 

I have always found toslink more rounded and less aggressive than coax. I should have kept it longer in the system.

I will do it again with more patience and care. The advantages are too interesting to overlook them.

Also i wonder if a "usb wireless extender" exists. I am searching for this.

Thanks a lot again, gino

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