Is my issue with Roon, or my Rpi or dietpi?

Turns out I can unplug the hub from power and the whole thing still works. Like I said…I have no idea why it works, but it does.

Heh… It wouldn’t - the Mojo has an internal battery and always runs from that. Input current only serves to charge the internal battery. But the power of our brain far exceeds that of the real world sometimes :slight_smile:

I don’t understand why you would have a split cable to begin with - the Mojo has 2 USB connections right?
One is exclusively for audio, marked with the USB symbol, while the other is exclusively used for charging the internal battery, is marked with a battery symbol and has an LED underneath showing the state - charging, charged, and different colours showing the remaining charge in the battery.

Note that each port is exclusively used for designated function, in particular, you cannot power the Mojo via the cable carrying the audio signal.

So, where does a split cable come in, if you have a different source for audio and for power (rPi and battery), and a different endpoint for audio and power (two ports on Mojo), respectively? I’m thinking of a Y split cable here, but if you have something else, I have misunderstood the whole thing.

Just run one cable from the rPi to the audio port, and another cable from your PSU of choice to the battery port.

As noted above, the Mojo never runs off the power supply, so you could use a wind turbine or a hamster for all it cares; it will not make a difference. On this topic, the manual specifically states that because of this if you use a weak power supply while playing music, the Mojo may take an extremely long time to fully charge.

Hi. This has nothing at all to do with the battery or providing power to the Mojo. Many dacs (not all) require a 5v signal over the incoming usb data stream to handshake with the source computer. Using a split usb cable is an attempt to keep computer generated noise ( a pi in this case) away from the incoming data stream and the dac. In my situation I am using a battery to generate the 5 volts. If you are using a dac that does not need to see 5v, you can either tape over the proper pin on your usb cable or buy a cable with that pin and wire removed. Noise is always the enemy. In my opinion of course.

I have a few questions you should feel free to ignore; remember I am not the enemy…
Why would there be noise? How is this noise affecting the digital signal over the USB bus? If you connected a hard drive, would this noise corrupt your files? What anti-noise measures does the posh cable, costing about half the price of the Mojo, might have? Have you seen this noise measured, or picked out reliably in blind listening tests? How low must be a noise floor before you cannot hear it?