[twylight]

With no source my new portable usb/dac/amp has audbile noise cranked past 40%

Other devices I own do not do this. Is this normal behavior? This include being on itunes with 50% level, 50% on PC, cranked past 40percent on usb dac amp with the music paused - I can hear noise.

I dont want to post the brand in case this is normal behavior. I can hear it with sure 530, 4x, 2x and some old as dirt sony full size closed cans.

With or without anything connected to it.

Thoughts?

 

[qusp]

yes with the music paused on some setups this does seem to be normal behavior. mostly with USB, USB is possibly the worst and noisiest form of digital signal around as it is easily contaminated by dirty power supply from within the computer.

the D10 via optical is totally silent with my SE530 right up to 100% on pause. Just tested it now

 

[twylight]

how about with nothing plugged in - ie no USB source - just the phones and the unit on...I would say it sounds like 'hiss' more than anything else - not grounding /EM noise (ive heard those before on other rigs)

 

[bakhtiar]

My iBasso D10 and nuforce IM are dead silent on USB-DAC mode, during pause, even at MAX volume.

Quote:

With or without anything connected to it.

So, even you are not connected to PC, you heard the noise? Then something is wrong with the amp.