Hiss and clicking noises as a USB DAC.

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1

Hello all,
Just a quick tip, i’ve been using UptoStream mini, Pro, Amp Mono and Amp 2.1.
I was always a little deceived by some faint background noises when my PC was connected via USB to the boards.
This affected the sound even if streaming via Wifi.
I realized that if i disconnected the USB cable, some noises disappeared.
Since i power my Amp boards via a the 24v input, i tried to modify a USB cable to only have the DATA connectivity, cutting the voltage (+ and -, red and black) of the cable.
This works wonderfully !!
So to prevent noises, get rid of the USB power if you can, try to move the WiFi / Bluetooth antennas around or disconnect them if you do not need them.

Just my 2 cents :slight_smile:

Pierrot

2

This is a common problem with all audio equipment, and it sounds like a ground loop in your setup.

Removing the ground on the USB cable sounds like a bad idea. Yes, it’s a differential signal, but this is not the proper solution.

My assumption is that you have a setup like this and you have a ground loop along the red line:

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image801×432 5.66 KB

If this is the case, the proper solution would be to install a ground loop isolator, or an isolation transformer between the DAC and the AMP.

An isolation transformer allows the signal to pass, but does not allow any current to pass. Amazon Search.

3

Thank you mclrkdev, but here i’m using the AmpMONO as a dac for the PC…
The PC is feeding the stream to the Arylic amp via USB.
I’ll try with the GND on, leaving the power cable out.

Yet it works fine right now, i guess the differencial nature of the D+ and D- signal is what makes it work right now.