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Vladimir's picture
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USB DAC Power Tweak
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Here is a cheap and easy tweak to get much better sound from your standalone DAC if its connected to your PC with USB cable.

Snip your USB cable +5V line from your PC to your standalone DAC if the DAC has its own power supply (charger).

 

If it hasn't buy USB hub with its own power supply, connect the DAC to the USB hub and your PC to the hub and then snip the 5V rail in the PC > Hub USB cable.

I can hear you all screaming at me. 

You don't have to cut the red 5V wire (red Vcc aka Vbus) to detach it. You can make a small piece of tape (electricians tape or any sticky tape) and put it over the pin that takes up 5V from your PC. This way when you plug the USB connector to your PC slot it wont have contact to the 5V power line.

 

In my case sound has improved, I just added the small piece of electricians tape over the 5V pin, so the tweak is reversable. Cutting the actual 5V red wire is a more permanent solution which you can do if you like the results. USB cable is cheap so nothing to worry about really.

Here is the full advanced tweak.  http://www.tnt-audio.com/clinica/221_diy_usb_e.html+

 

How to defuse an atomic bomb?

 

 

Carefully. 

 

Have fun now! 

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RE: USB DAC Power Tweak

Here's mine. 

 

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RE: USB DAC Power Tweak

For best performance from any music device (Including a DAC) always connect directly to the computer, never through a hub. (Any one that uses pro audio equipment will tell you this)

Disconnecting the +5v wire will make no difference to any decent USB music device, so if you can hear a difference stick your DAC on eBay and buy a decent one. (Check out pro audio shops rather than Hi Fi shops)

Hope this helps

Bill

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RE: USB DAC Power Tweak

abacus wrote:

For best performance from any music device (Including a DAC) always connect directly to the computer, never through a hub. (Any one that uses pro audio equipment will tell you this)

Disconnecting the +5v wire will make no difference to any decent USB music device, so if you can hear a difference stick your DAC on eBay and buy a decent one. (Check out pro audio shops rather than Hi Fi shops)

Hope this helps

Bill

 

I use 7m USB cable and without a hub I have droputs. I bought my DAC from a pro audio shop. It's actually an audio interface, not a "hi-fi DAC". 

Next naysayer please. 

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RE: USB DAC Power Tweak

Vladimir wrote:

I use 7m USB cable and without a hub I have droputs.

The USB 2.0 spec only accounts for a maximum cable length of 5 m. I actually found a couple of vendors that recommend not using cables longer than 3 m. This is important to avoid losing frames in the cable. The more frames that are lost due to collision, the worse the audio quality.

Arcam irDac • A19 • P38 • Kef R100

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RE: USB DAC Power Tweak

No problems whatsoever since I got the hub. The dropouts were power related, not data. On long or short lead, the sound quality is the same, tested many many times with 0.5m, 3m, 5m and 7m cables.

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RE: USB DAC Power Tweak

Vladimir wrote:

No problems whatsoever since I got the hub. The dropouts were power related, not data. On long or short lead, the sound quality is the same, tested many many times with 0.5m, 3m, 5m and 7m cables.

I thought that you had just put tape on the power lead of the cable because you did not need it… :grin: Jokes aside, I think it would be more likely that the dropout had to do with the data than with the power, but since it doesn't happen anymore, all is well.

And if the audio through the 7 m cable sounds the same to you as through a 3 m cable, and you find that interrupting the USB power line improves things, that's all that matters.

:cheers:

Arcam irDac • A19 • P38 • Kef R100

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RE: USB DAC Power Tweak

I stopped having data dropouts with my 5m and 7m cable once I introduced the hub. Didn't tweak that combo for a year and worked great.

The USB cable from the PC goes to the Hub first, then to the DAC. The external power supply of the Hub provides the needed 5V for the DAC to work. I measured from my laptop the 5V are actually barely 4.4V or less and not stable. 

Sending 5V to a DAC that already uses its power supply is unneccessary introduction of noise. The cheaper the DAC, the bigger the benefit from the tweak.

There is a part two in this tweak. No charger at all, just use batteries as power source. Mwahahaha!  

 

 

 

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RE: USB DAC Power Tweak RE: USB DAC Power Tweak

Vladimir wrote:

I stopped having data dropouts with my 5m and 7m cable once I introduced the hub. Didn't tweak that combo for a year and worked great.

The USB cable from the PC goes to the Hub first, then to the DAC. The external power supply of the Hub provides the needed 5V for the DAC to work. I measured from my laptop the 5V are actually barely 4.4V or less and not stable. 

Sending 5V to a DAC that already uses its power supply is unneccessary introduction of noise. The cheaper the DAC, the bigger the benefit from the tweak.

There is a part two in this tweak. No charger at all, just use batteries as power source. Mwahahaha!  

 

 

 

 

This is actually a proven tweak  for cheap USB powered DAC Smile 

The dropout is most likely happen to due the insufficient power of the USB port that most user facing Biggrin  

Solutions that most users practised are using Y USB cable, powered USB hub or powered pci usb card. 

From my experience, after u modified using battery as power source, try plugging ur USB cable to the hub and also straight to the PC. Sound should sound different.

Which sound the best is actually up to personal preferences imho.  Smile Although, some said plugging straight to the PC sound better. But, during my case last time, plugging straight to the PC sound harsh and non relaxing.

However, after changing my USB cable, now I prefer plugging straight to my PC. Have fun tweaking around as I found any small changes do make sound different I-m so happy

 

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RE: USB DAC Power Tweak

If you are only getting 4.4V then it is the interface in the Laptop that is substandard, however try what most USB external HDD manufactures do and use 2 USB outlets to increase the available current available. (A hub can introduce timing issues, however if you have no option but to use one then make sure the hub isolates the USB ports from each other, and keep the lead from computer to hub as short as possible)

Hope this helps

Bill

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RE: USB DAC Power Tweak

Nope. No timing issues here, everything is synced and responsive.

 

Thanks Bill

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