Rhythmic noise issue from Nucleus Rev B with Anthem STR preamp/DAC via USB (ref#RMVYQP)

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1

Select your Nucleus model from the list below

· Nucleus Rev B

I'm having trouble with my Nucleus hardware

· Other

Select the option that fits best

· The Nucleus boots up and I can connect to it in the Roon app without issue, but I have a question about configuration/storage/attached devices

Describe the issue

I use a Nucleus (Rev B) as a streamer, connected by USB directly to an Anthem STR preamp/DAC, which I recently purchased. When the system is powered, I hear rhythmic, digital-like noise at the speakers and subs. I traced the noise source to the Nucleus. When the room is quiet, I hear the same soft noise pattern inside the Nucleus' case as is being amplified to the speakers (sort of like a repeating HDD access noise pattern). The noise at the speakers stops when I disconnect the USB cable or turn off the Nucleus. I've tried different USB cables and both Nucleus USB ports with no effect.

Could there be a problem with the Nucleus that is causing this noise to leak across the USB cable? The previous DAC and preamp components were Benchmark Media units. I used the Nucleus connected to the BM DAC for a year and never noticed any such noise at the speakers. During my troubleshooting, I discovered the Benchmark preamp seems block/suppress this noise from reaching the analog outputs. So I hadn't noticed it before.

I contacted Anthem support and they indicated there is no setting in the Anthem that could explain the noise bleeding to the analog outputs.

2

Can you insert a Raspberry Pi 4 connected by ethernet (or WIFI) with USB to your DAC to eliminate the direct connection from the Nucleus? That’s how I have mine set up.

3

Some DAC USB receiver implementations aren‘t especially immune to EMI, so yes!

It‘s easier and without any IT administration efforts to use real galvanic USB isolators, like the ones tested by Archimagos Musings.

From my own experience, I can vouch for the Intona units.

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4

Thanks for the advice, @Marin_Weigel and @Jim_F. After reading the Archimagos articles, I ordered a Topping HS02 USB isolator. I’ll follow up after trying it.

If that doesn’t work, I may need to get a proper streamer and relegate the Nucleus to Roon server duties on it’s own network cable from the router. My last resort.

5

Your Nucleus should definitely be connected to your network by ethernet regardless.

6

Hi @rhythmjunky ,

Yes, this does sound like electrical noise, let us know how the USB isolator solution goes!

7

Quick follow up. The Topping HS02 USB isolator stopped the noise that was leaking through the Nucleus-to-DAC USB cable. I no longer hear it amplified at the speakers/subs. So, that’s a major plus.

I have not listened enough to tell if the isolator degrades fidelity in any way. The Archimagos articles seem to imply fidelity should not be affected, either for the good or bad. I’ll let my ears be the judge over the coming weeks.

Thanks again for the suggestions.

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