Usb extenders on rj45 cable.

Hi!
sorry if i jump in with a weird question.
Yesterday i connected a usb dac/headphone amp to the pc through an usb extender on rj45 Ethernet cable.
It is made with 2 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).

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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 ?
Thanks a lot, gino
 
Last edited:

Ben Mah

Member
Paid Member
2012-05-18 6:36 pm
Vancouver
Yes, you could be hearing an improvement. There have been many USB improvement devices out lately, and the latest trick is to isolate the usb source through ethernet.

PS Audio has actually just announced a similar device called LANRover, which is an USB extender as is your device. Speculation is that it is based on an oem Icron usb extender that has LAN capability.
 
Yes, you could be hearing an improvement.
There have been many USB improvement devices out lately, and the latest trick is to isolate the usb source through ethernet.

Hi and thanks a lot for the very kind and valuable advice.
I have read a lot about various accessories used on the usb connection between pc and audio peripherals.
They can be grouped in two main families depending on their function:
1) galvanic isolators
2) usb signal re-clockers/regenerators

If i understand rightly, in the first case the goal is to impede the pc noise to reach the usb dac
In the second case the goal is to provide the usb dac with a stronger and cleaner signal (i.e. with a better S/N ratio).
Many people swear about their efficacy.

About the usb extenders over rj45 cable

As usual i started cheap and made a wrong selection.
These ones i have are usb 1.1 only compatible. And they work with one usb dac but they causes clicks on another better quality.
So i have bought these ones instead now

USB 2 0 RJ45 Extender Repeater with Power Adapter Up to 100M 330ft | eBay

Description:
This USB extender can easily send the USB signals via Cat.5/5e/6 cable up to 100 meters (196 ft) at data rate of High Speed (480Mb/s) , Full Speed (12Mb/s) and Low Speed (1.5Mb/s). Without any configuration or software driver, this USB extender allows you to extend your USB device or hub up to 100m from your computer, which overcomes the typical USB cable limitation.It is suitable for USB cameras, printers,web cams ,key board/mouse extensions, and any other USB device.

so speed should not be an issue. A very good way to check is to connect a web cam at the receiver end and see for any lag or problem of fluidity in the images. The better the connection the more fluid the images.
Very simple test and very very telling about the quality of the connection.
With my current ones the image is very lagging ... a lot indeed actually.

Next step would be to powered the 1st box, the sender, with an external power supply to isolate it and so everything downstream of it from the pc power.
I am very curious to listen.

Unfortunately and as usual the best professional extenders come not cheap.
Geffen is a very good brand because they have a huge experience in video transmission. They are very expensive but very very high quality.
What amazes me is that extenders can transmit a usb signal up to 150 meters distance !!! just compare this with the 6 meters max of a usb cable.

PS Audio has actually just announced a similar device called LANRover, which is an USB extender as is your device.
Speculation is that it is based on an oem Icron usb extender that has LAN capability

Yes i read something. But i am not very interested in lan devices. I have just one main audio/video source that is my pc. For the other rooms i can live with lesser systems without the least problem.
Only for the living room i would like something better.

On Youtube there are many videos about these extenders

https://www.youtube.com/watch?v=LutDe6YcsQw

https://www.youtube.com/watch?v=b4HcwX8d56M

https://www.youtube.com/watch?v=fmOwy9ysvr8

Thanks a lot again.
Regards, gino
 

Ben Mah

Member
Paid Member
2012-05-18 6:36 pm
Vancouver
Yes i read something. But i am not very interested in lan devices. I have just one main audio/video source that is my pc. For the other rooms i can live with lesser systems without the least problem.
Only for the living room i would like something better.

I mentioned the lan capable usb extender because I read some forum posts on Head-Fi.org that lan capable extenders provide better isolation than non-lan capable extenders. Whether or not that is true, I don't know and I am not going to explore that.

I am thinking of going down a different path by getting rid of the usb connection between computer and dac, with an I2S output capable single board computer such as an Odroid C2 to connect to my dac, which has Iancanada fifo, clock, and reclocking.
 
I mentioned the lan capable usb extender because I read some forum posts on Head-Fi.org that lan capable extenders provide better isolation than non-lan capable extenders. Whether or not that is true, I don't know and I am not going to explore that.

Hi ! i see. I am still curious about this conversion from usb to Ethernet.
I will look in internet and i will open the sender and peep inside.

I am thinking of going down a different path by getting rid of the usb connection between computer and dac, with an I2S output capable single board computer such as an Odroid C2 to connect to my dac, which has Iancanada fifo, clock, and reclocking

Interesting. I have some units that accept I2S. Problem could be that there is not a standard pinout. I would like to see what i can get from USB.
Some people swear of very good sound also from usb dacs.
Thanks again, gino
 
You can also use active USB extenders - I mean the ones that are one long cable with repeater boxes moulded onto the cable every 10m or so. The extender box on the cable is actually a USB hub. I have a 20m one of these and when connected between my mac mini and Audiolab CDQ DAC it sounds better than with a short cable. This is because the USB packets are being buffered and the retransmitted by the hubs.

I also have a USB galvanic isolater - with the DAC side powered from a separate linear pss, to avoid noise from the mac mini 5v rail.

The 20m USB cable with its two built in hubs makes a much bigger improvement than the galvanic isolator to sound quality. I would not have believed this before trying it.
 

easp

Member
2016-05-29 9:35 pm
I don't see any of the small isolation transformers required for Ethernet...

In the second case the goal is to provide the usb dac with a stronger and cleaner signal (i.e. with a better S/N ratio).

A stronger and cleaner signal to a USB DAC? That's just silly. About all you can hope for is a reduction of jitter, which is probably already at or near the limit of perceivable, and completely irrelevant if you are using async DAC in the first place.

Many people swear about their efficacy.

Yes, and I've seen people swear that using an optical USB extender to connect the hard disk to their music server, which then just pushes out data over ethernet to a separate device with a DAC, really improves the low end. Or that a cryotreated electrical outlet makes a huge difference, even when plugged into a regular electrical outlet. People can convince themselves, and others, of all sorts of nonsense. It's still nonsense.