USBridge & ISO-DAC

I’m running Volumio (2.348 as is required I believe) on the Allo Sparky SBC with the Allo USB board - this is the USBridge package.

My Metrum DAC plays fine and is discovered as UAC2. My Ciunas Audio ISO-DAC which has an Amanero USB receiver is not recognised. I’ve performed Factory Resets in the hope that Volumio would recognise the DAC at initial startup but it only offers HDMI as an option so it’s not seeing the DAC.

The ALSA message I see is: Error: Failed to open “alsa” [alsa]; Failed to open ALSA device “hw:1,0”; No such file or directory

Does the DAC need alternative firmware or can something be done at the Volumio end?

Hi, I’m the manufacturer of the ISO-DAC that Clive is having an issue with & I thought I would participate here in trying to solve this issue.
Let me explain the hardware configuration that might be relevant to this. The ISO-DAC consists of a USB isolator + USB hub + USB DAC in a single case. All these elements are powered up at the same time which is no problem for any other computer i.e. the USB is recognised & a little later the USB DAC is enumerated.

I’m no ALSA expert but one thing occurs to me - is it possible that the USB enumeration of the hub needs to happen before the USB DAC (as would be the case for most USB hub setups)?

Today I tried an experiment with another DAC. I used a Regen (hub/regenerator) into the USB of the Metrum DAC - this dac worked fine on its own.

Switch on sequence:

Regen - USBridge - Metrum (once SBC booted) - this works

Regen & Metrum pre-started then USBridge - same ALSA error as ISO-DAC

The error was bad enough for me to need the do a Factory Reset as it wouldn’t play even after a reboot with the “good” startup sequence.

It seems USBridge or more likely Volumio can’t cope with a hub and dac unless they are powered on carefully in sequence. This isn’t a problem with a PC.

Reported the same type issue , issue was ISO dac connected on USB 3.0 port of Sparky.

This dac detected properly on USBridge port. ( USB HOST marked on USBridge case).

Please ensure the DAC connected to the USBridge Port.