USB powering

[docvale]

I have learnt about a USB power supply from iFi Audio (a spin-off company from AMR), conceived for USB powered DACs.

I have seen interesting graphs, showing that this device lowers the noise pushed by the USB output from, for example, a MacBook Pro.
If it is clear that it might improve the performance of a DAC which is just powered by USB (e.g., HRT Streamer, Audioquest Dragonfly), I was wondering if it might be beneficial for higher end DACs.
So my question:
Does a DAC that has its own power supply need also its USB input to be powered by the computer?

 

[DasguteOhr]

Hello Valerio,

easy to proof isolate Pin 1 of your USB-A Connector(Computer),if its work your Dac powered
the USB-Chip,if not you have no Signal.
See LinK Post 10#
http://www.computeraudiophile.com/f...dding-usb-cable-power-dac-external-psu-15714/

It sounds much better with the Isolated Pin..Sorry for my English.

LinK to Accu-Pack and Isolated Cables

http://www.elijahaudio.com/

Best Regards,
Stephan

 

[Phelonious Ponk]

I have learnt about a USB power supply from iFi Audio (a spin-off company from AMR), conceived for USB powered DACs.

I have seen interesting graphs, showing that this device lowers the noise pushed by the USB output from, for example, a MacBook Pro.
If it is clear that it might improve the performance of a DAC which is just powered by USB (e.g., HRT Streamer, Audioquest Dragonfly), I was wondering if it might be beneficial for higher end DACs.
So my question:
Does a DAC that has its own power supply need also its USB input to be powered by the computer?

It needs USB input to get the data. Does it need the USB pin that carries bus power? No.

Tim