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Redundant 5v USB connection-bad or inconsequential?


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My DAC (NAD M51) still works fine fed from USB if I cut the 5v power leg on the cable (red wire). Does this suggest that, even with a regular USB cable, the computer's 5v supply is not utilized in the circuit at all, and having no potentially detrimental effect?

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My DAC (NAD M51) still works fine fed from USB if I cut the 5v power leg on the cable (red wire). Does this suggest that, even with a regular USB cable, the computer's 5v supply is not utilized in the circuit at all, and having no potentially detrimental effect?

 

In my experience, unless the USB +5V supply is required for "handshake" or powering reasons, it is best to keep it out of the USB cable due to coupling of the noisy SMPS +5V USB wire into the data lines, which are in a typical USB cable not screened from each other, and rely on the noise rejection of being a twisted pair, just as in analogue telephony cables.

 

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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Without damaging the USB cable you can put a tiny bit of plastic in the connector to block pin 1 (5v). I have used a bit of the plastic used in the collar of a dress shirt.

 

But don't forget that noise can come in through the signal ground (pin 4) and the connector ground shield as well.

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  • 2 weeks later...

To follow up on my last post, I received the Elijah Audio ISOLATE Cu USB cable, and have 25 hrs. on it so far. I think this is a great solution if your DAC, like my NAD M51, does not require external 5v USB power. It certainly makes more sense than buying an expensive twin-lead USB like the Light Harmonics, and leaving the power leg unplugged and dangling.

 

This cable is custom-made from cryo-treated Audience wire, braided, and encased in several layers of natural cotton insulation. The connectors are attached with Cardas Eutectic solder.

The cable has no 5v power lead or pins for it in the connector plugs. And, similar to the Mapleshade USB cable, no shielding, which can potentially be a conduit for computer noise.

 

This cable is a keeper. On my rig, the ISOLATE sounds beautiful, even smoother than my Kimber Kable silver USB, which is now going bye-bye on ebay.

 

The 1.0 meter Elijah cost me $180 plus shipping. Shorter ones are less. Contact Michael at Elijah--he's very responsive. He was able to make my cable and send it out in just a few days. Shipping from Australia to New Jersey cost $20 and took just over a week.

 

Elijah Audio

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Congrats!

 

I am currently using an Audioquest Diamond USB with both Power and Ground taped for no contacts on the computer side. It works great. Also using an Aubisque before Nad M51. I am still experimenting since I felt that Ifi Iusb were to many connections before the converter.

 

Keep us updated if you find improvements by lifting the ground also?

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You need the ground for device identification and operation. If you cut the ground (black wire) you will then be relying on the potentially noisier shield for this function, as the 0 volts and shield connections are normally connected internally in the device itself .

 

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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Anyone had any experience with the Mytek & the Elijah Isolate CU usb cable? Or any other powerless usb?

macmini M1>ethernet / elgar iso tran(2.5kVa, .0005pfd)>consonance pw-3 boards>ghent ethernet(et linkway cat8 jssg360)>etherRegen B-side(js-2)>ghent ethernet(et linkway cat8 jssg360) >ultraRendu A-side(clones lpsu split>lps1.2)>uspbc>iso regen(clones lpsu split>lps1.2)>curious regen link>rme adi-2 dac(js-2)>cawsey cables>naquadria sp2 passive pre> 1.naquadria lucien mkII.5 power>elac fs249be + elac 4pi plus.2> 2.perreaux9000b(mods)>2x naquadria 12” passive subs.

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