Nucleus - No Audio Devices Appearing (Hegel H390)

Core Machine (Operating system/System info/Roon build number)

Nucleus Core, SN: 54B2038BD321

**Network Details

ASUS Bridge, ethernet hardwired Nucleus and Hegel H390 integrated amplifier

Audio Devices (Specify what device you’re using and its connection type - USB/HDMI/etc.)

Nucleus Core + Hegel H390 (USB)

Have used my Nucleus Core for about a month. All of a suuden, it doesn’t recognise my Hegel amp anymore. Tried to restart the Nucleus Core, my internet and my Hegel amp., but the issue persists. The Nucleus apparently no longer “sees” my Hegel amp.

When I hook up my Hegel amp with my Apple laptop PC, it immediately finds the amplifier and plays, so I am quite convinced the issue at hand relates to the Nucleus Core.

Can you help?

Many thanks and best regards, Anders

Hello @Anders_Trojel,

Welcome to the forum and apologies for the delay in getting back to you here due to the holiday weekend.

Can you please confirm if you are able to see any other audio devices in Roon Settings -> Audio and the Hegel is the only device missing or are others missing as well? Could you please share a screenshot of your Roon Settings -> Audio tab?

Hi again. I’m only using my Hegel H390 as audio device with my Nucleus Core. How can I upload a screen shot pic from my iPhone in this menu?

Best regards,


Hello @Anders_Trojel,

You can upload screenshots by clicking the “image” button on our forum:
Image Upload

Thanks, here’s the screenshot.

Launch /Applications/Utilities/System Information

On the left sidebar, click on USB

Do you see the Hegel in the list of attached USB devices?

I’m doing this from an iPad. Where in the settings menu do I find the submenu you are eluding to? Can’t see launch/applications tab anywhere.

Sorry, I saw “Safari” in one of your screenshots and assumed Mac. Unfortunately, with the Nucleus, you can’t log in to see the USB device enumeration. I assume you can submit logs to Roon for them to review what USB devices its seeing.

So what exactly do we do now? My Nucleus Core is not working after only one month of use. Really hoped you guys would be able to help me get this sorted. How am I supposed to send USB data from my Nucleus to Roon?

Hello @Anders_Trojel,

Thanks for the screenshot. Since no audio devices are appearing at all, I suspect that this is a deeper issue than just the Hegel.

I have gone ahead and activated diagnostics mode for your Nucleus and what this action does is automatically upload a log-set to our servers next time the Nucleus is online.

Can I please ask that you reboot your Nucleus and let me know once you have done so, and I will check for this diagnostics report?


Hi Noris,

Roon Nucleus rebooted, online and connected with Hegel amp. Hope your remote test works out.

Best regards,


Hello @Anders_Trojel,

Thanks for letting me know the Nucleus has been rebooted, I can confirm that the diagnostics report has been received.

Sometimes, errors like the one you saw can be spurious, but unfortunately in this case there are signs of low level corruption in your database.

This type of error is extremely rare for us and not one that we see often. Our database infrastructure is designed specifically to prevent this type of corruption, and we don’t take this class of issue lightly.

We’ve traced a few reports like this in the past to hard drive integrity issues but generally speaking, this means that Roon is reading information from your hard drive that is different from what was originally written, and the database is now unable to load properly.

What’s Next?

If you’ve been making regular backups, my advice would be to install Roon fresh on your Core machine, and roll back to one of your backups. You can use these instructions to do so:

  • Stop RoonServer from running in Nucleus’s WebUI
  • Navigate to your Roon’s Database Location
  • Find the folder that says “RoonServer”
  • Rename the “RoonServer” folder to “RoonServer_old”
  • Restart the RoonServer in the WebUI to generate a new Database
  • Restore from backup at least a week before issues started

If the database loads properly, your edits, playlists, tags, etc should be intact, and we can confirm everything is performing properly once it’s been restored.

If you do not have any backups, unfortunately you will need to start with a fresh database.

Again, this class of issue is extremely rare for us and you have our apologies for the trouble here.

Thanks for your guidance, Noris. Just to clarify, I’m not using a Mac or Windows PC to manage any databases related to the Nucleus Core. I’m only using an iPad and my iPhone as “remote control”. The only database I’m using is an external hard disc with my music files in various formats.

In view of the above, how do I reformat the Nucleus Core without using a PC as my

Many thanks & BR.


Hi @Anders_Trojel,

Can you please try to open up your Nucleus Web UI and perform a Database Reset?

ROCK Database Reset

Thank you, this seemed to work. After also reinstalling my Roon App the Nucleus has found my Hegel amp again and it’s now playing.

1 Like

Hi @Anders_Trojel,

Glad to hear that the fresh database helped resolve the issue here!
If you run into any further difficulties, please do feel free to reach out to us once more, thanks!

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