I2soverusb - popping noise at startup

[lordearl]

I've recently assembled a USB DAC with JLSOUNDS I2soverusb board with an I2S implementation of an AD1865 DAC.

The sound is perfect but when the DAC is 'engaged' by the PC/USB device there is a loud thump.

I have checked a few tests now - MOODE, VOLUMIO and USB AUDIO PLAYER PRO.

I can confirm each time the popping noise only happens when the player is 're-set'. For example, if the USB AUDIO PLAYER PRO app is closed and then re-opened, and the connection to the DAC is refreshed, there is a large pop. Or if I restart Volumio or Moode, it will give the loud popping noise. This happens whether using AC power or on battery of the computer.

I don't have a USB isolation device to break the ground to test, but I don't think it relates to a grounding issue.

Would adding a mute circuit assist in this case, or is there another work-around (apart from leaving the PC and DAC on 24/7!)?

 

[Markw4]

Don't have that problem here, but I2SoverUSB does have MUTE that you can check with a scope, or maybe even a DVM if you can set it not to auto-range. It might be asserting MUTE until it has stabilized. Have to check though.