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Length of usb cable ?


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Hi everyone.

Have a question, I am thinking about changing my cd player, the Meridian 588 to something better, this is my system.

Meridian 588 cd player

DK Design VS.1 Reference MK2 Integrated amp.

Amphion xenon speekers.

I am interested in using my MacBook Pro with a usb cable to my hopefully new dac in not so far future, how long can the usb be?

Thanks.

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Hi everyone.

Have a question, I am thinking about changing my cd player, the Meridian 588 to something better, this is my system.

Meridian 588 cd player

DK Design VS.1 Reference MK2 Integrated amp.

Amphion xenon speekers.

I am interested in using my MacBook Pro with a usb cable to my hopefully new dac in not so far future, how long can the usb be?

Thanks.

 

Conventional wisdom says 5M, but this company makes them up to 15M. They say the cable is impedance balanced enough to work. Perhaps if you use a supplementary power source, such as the iFi micro iUSBPower, that would help. Maybe superdad or JohnSwenson will weigh in on this.

 

http://stores.ebay.com/sjofnhifi?_dmd=2&_nkw=USB

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The official maximum length of cable is 5M. According to the spec it has nothing to do with the cable quality, but is a timing issue of sending a command to the device and getting a reply back in a certain period of time. If the device responds faster than the amount of time allocated in the spec then you could get away with a longer cable, but you could not guarantee it would work with all devices.

 

John S.

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I see, have been looking at a Primare dac30 to connect to both my Meridian and my laptop, it would be nice to not have to get up from the chair to change tune all the time;-)

Therefore the question about the length of usb.

Answers are much appreciated.

 

I recall quite a few years ago, that a maximum run of USB needed a powered hub in the middle (maybe one at the end too ?). I acquired 2 long cables and hub(s). to connect my laptop in one room with my audio system in another. But I went in a different direction and never did set up that long run.

 

Perhaps the intermediate hub(s) alleviate the timing issues John S. mentioned ??

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When higher PCM rates above 96Khz and USB Audio Class 2 for OSX were pioneered a 'few years ago' now (!), the cable length limit was a dilemma for sure. The problem was as John Swenson replies, whether the device and the host 'click'. Some USB cables at the time were fitted with ferrite cores, made things worse for longer or shorter cables depending if a 192Khz signal was transmitted.

5m is about it these days, with 2m or shorter, the better, no ferrites. As to the choice of cable...whatever appeals to you is fine. Far too many pages devoted to differences of opinion as far as cables go, whether speaker, interconnect or power, the topics go on forever with no conclusion. I will say though, look for a cable that's durable and has connectors that don't readily corrode for long term use. There's gold and there's gold plating same with nickel.

 

S/PDIF is about the same limitation, AES3 (or its newer numbers) to 100m.

 

At this point in time, there are some movements forward regarding audio transmissions. Merging Technologies are about to release (maybe by RMAF 2015???) their NADAC, a DAC that uses Ravenna protocol over Ethernet, overcoming short cabling restrictions while using existing Ethernet networks. So far only one DAC we know of using Ravenna, fingers crossed maybe more.

AS Profile Equipment List        Say NO to MQA

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The official maximum length of cable is 5M. According to the spec it has nothing to do with the cable quality, but is a timing issue of sending a command to the device and getting a reply back in a certain period of time. If the device responds faster than the amount of time allocated in the spec then you could get away with a longer cable, but you could not guarantee it would work with all devices.

 

John S.

 

Hi John

Have you ever compared the waveforms going into the differential receiver with both a 1M cable length and a 5m USB cable length ?

 

Regards

Alex

 

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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Hi John

Have you ever compared the waveforms going into the differential receiver with both a 1M cable length and a 5m USB cable length ?

 

Regards

Alex

 

I don't really have good enough equipment to do a really good job of that. Other people have and can see significant differences as the cables get longer. Of course it depends on the cable, really good ones have much less degradation with long cables.

 

John S.

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I recall quite a few years ago, that a maximum run of USB needed a powered hub in the middle (maybe one at the end too ?). I acquired 2 long cables and hub(s). to connect my laptop in one room with my audio system in another. But I went in a different direction and never did set up that long run.

 

Perhaps the intermediate hub(s) alleviate the timing issues John S. mentioned ??

 

Yes, the timing loop is from host to device to host, in the case of a hub the timing loop is from host to hub to host, and from hub to device to hub. You can stack hubs (usually up to 5 hubs) each of which has a a 5 meter length limit. BUT all these hubs need to be self powered not bus powered, you are not allowed to plug a bus powered hub into another bus powered hub. Theoretically the last hub in the chain can be bus powered.

 

Thus you cannot chain the "active" cables (which have a bus powered hub at the end) so the max with these is 10M.

 

There are other limitations too, a bus powered hub is only allowed to power 100mA to any device. Thus if you have a bus powered DAC which tells the computer it will use 300mA, and you plug it into a bus powered hub, the computer will not connect to it, even if that is the only thing plugged into the bus powered hub.

 

John S.

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I don't really have good enough equipment to do a really good job of that. Other people have and can see significant differences as the cables get longer. Of course it depends on the cable, really good ones have much less degradation with long cables.

 

John S.

 

Leaving aside for a moment the maximum length of cable that will "work" what are the sound quality benefits of cable length?

Perhaps jitter induced by reflections may be a factor.

A few manufacturers favour a very short USB link which I assume means any reflections of the signal caused by less than perfect termination will be so close in time to the original as to not matter.

Others feel that at least 6 feet of cable is needed to attenuate and space reflections away from the original so that they can be ignored.

I wonder if anyone has compared 6 inches to 6 ft of the same cable between computer and DAC?

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82ft 25M USB 2.0 A Male to A Female Active Extension / Repeater Cable (Kinect & PS3 Move Compatible Extension) - Monoprice.com

 

This one is 82 ft. (25 meters), and they are available in shorter lengths. I have used them. They do 192/24 with no issues. Buy some, use them, they work problem solved.

 

For the past 4 months I have been using a quiet desktop server to feed my main system via USB. I have a 33 ft Monoprice active extender on that connection, and it sounds just fine. This let me position the computer away from the rest of the stereo in a more convenient location.

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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Does anyone have an opinion on this sort of solution and if it adds jitter or other artifacts to 192/24 and DSD files?

 

82ft 25M USB 2.0 A Male to A Female Active Extension / Repeater Cable (Kinect & PS3 Move Compatible Extension) - Monoprice.com

 

This one is 82 ft. (25 meters), and they are available in shorter lengths. I have used them. They do 192/24 with no issues. Buy some, use them, they work problem solved.

 

For the past 4 months I have been using a quiet desktop server to feed my main system via USB. I have a 33 ft Monoprice active extender on that connection, and it sounds just fine. This let me position the computer away from the rest of the stereo in a more convenient location.

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Does anyone have an opinion on this sort of solution and if it adds jitter or other artifacts to 192/24 and DSD files?

 

I have used these on and off for a few years. Recently full time in my main rig. Also have used the 50 ft version.

 

At one time I did lots of null measurements with these compared to a one meter USB cable. I was not able to find anything they changed in the resulting analog output of the DACs I had on hand. The limits of my measures would have shown jitter once it reached 300 picoseconds or more. Noise at around the 20 bit level. Whatever it did was below this level. I believe it contributes close to nothing to an audio signal.

 

Jitter is from timing variations, and the stream of data over USB has no timing information. The timing takes place at the other end in the DAC itself. Noise on the USB has some slight chance to effect the accuracy of the clock in the DAC. Any such noise is at a very low level on these active extenders. Better DACs will isolate such noise from the clock itself for the most part.

 

If you don't believe it, at these prices, just give one a try. Trust me, what it does is little to nothing. If you have need of one it will work. If you think it is a slight negative you have lost $33 or less. You'll find it doesn't hurt a thing.

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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