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Does anyone here make any special efforts to block the power in their digital USB cables?
It is said that most Dac's don't need or use incoming USB +5v however if received the +5v could hurt the sound quality.
Any experience with these or changes in SQ when blocking +5v in the USB cable?
Thank you
J.
Follow Ups:
In the old days when I used a iBook as a source, I used a USB cable that eliminated the 5v line. It fed a modified usb to spdif converter and It was the best sound I got out of that laptop.
My experience is getting rid of any noise (not the audible kind, but the stuff that goes for a ride on wires from component to component) helps digital sound more natural and relaxed.
. . . there should be nothing to receive the 5V line at the other end.I've had two DACS (LKS and Musetec) that provided the 5V internally to their USB to I2S board. I tried blocking the 5V as per Abe, and it made no difference at all.
This sort of arrangement has two advantages. First the 5V provided to the incoming board can be as clean as the designer wishes and designs for. In the case of the Musetec it is provided by a bank of super capacitors.
Second, the data lines on the USB cable are thought by some to be compromised by the 5V running through the cable. Hence the various designs in some cables separating the 5V line from the rest.
Edits: 09/01/24
"It Should Not Hurt Sound Quality Because . . . . there should be nothing to receive the 5V line at the other end."It depends on the DAC. Many DACs -do- need the 5V while some do not.
Some DACs -require- the 5V Vcc over USB continuously or momentarily while others don't need it at all. That's one of the reasons for experimenting by blocking the 5V line in the USB-A connector. If the DAC stops working after blocking the 5V then you have just determined that your DAC -requires- the 5V over USB to function. If that is the case you can then break the 5V line and inject your own 'clean' 5V to see if it helps SQ. YMMV.
In my experience I've owned DACs that required the 5V over USB and others that did not. There was no correlation to suggest improved SQ from DACs that did not require the 5V. In fact, I had an Ayre DAC that did not require the 5V over USB at all but my PS Audio DAC does. It sounds ever so slightly more to my liking so I kept it. Sold the Ayre DAC long ago.
Edits: 09/02/24 09/02/24
It's called handshaking. All DACS need that pin 4 ground for the handshake even if they don't use the 5V from the USB cable. There are those who disconnect the ground after the connection is made. They claim improved SQ. Others have the ground connected via a resister--a half-way measure.Of course fine DACS have been made which need the 5V on the USB cable as wll as those which don't. But there can be no doubt that a good engineer can improve his product assuring a cleaner 5V line than can likely be provided through the USB cable.
Edits: 09/02/24 09/02/24
Second, the data lines on the USB cable are thought by some to be compromised by the 5V running through the cable. Hence the various designs in some cables separating the 5V line from the rest.
I can see this being the case to some extent.
J.
I wrote about this in 2016 at the link below. I didn't notice a SQ difference but some DACs don't even 'look at' the 5v coming off the USB cable. Others require it constantly in order to work. Others might need the 5v just briefly to initialize.You can completely cut the USB 5v to some USB DACs and leave it at that or....
If the DAC needs it, you can supply your own 'clean' 5v by making a break in the USB cable 5v line then injecting your own 5v. There are pre-made USB cables for this purpose.
You can also experiment with galvanic isolation which was a hot topic here several years ago. But honestly most modern DACs incorporate galvanic isolation internally.
Edits: 08/31/24
Thanks Abe,
Fortunately none of my Dacs need the +5v so I just used a small piece of electrical tape via a toothpick to block the +5v pin.
I had a lengthy discussion with a Luxman rep at an audio show here in Fukuoka a couple of months ago. I was inquiring about their new Dac which is supposed to be released this Oct. he made it clear that their Dac does not accept incoming +5v for this very reason.
I'll probably write a small review once it comes in, hope sooner than Oct.
J.
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