Your DAC does not seem to use USB power, is most likely asynchronous USB (uses XMOS receiver), so IMO any highspeed isolator (real isolator, not some USB filters marketed as "audiophile isolators") including inexpensive ones from aliexpress (e.g. https://www.aliexpress.com/item/1005008091400900.html) would do.
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Buzz when GPU is loaded
- Thread starter MKreroo
- Start date
Conclusion from my tests.
I can generate the worst type of "fart sounds" like my kids call it, by moving on a 3D object in Fusion 360 CAD software.
The Sbooster Vbus2 USB Isolator, that I found at a local hifi store for $30, did nothing!
A 10 meter power cord connected to the Wavebourn Edelweiss 3 Power Amp (tube headphone amp) managed to reduce the annoying "fart sounds" substantially, but this option is not very WAF. It seems any outlet at least 5 meters away from the computer is better than any USB Isolator. Sorry to burst your dream bubble!
I can generate the worst type of "fart sounds" like my kids call it, by moving on a 3D object in Fusion 360 CAD software.
The Sbooster Vbus2 USB Isolator, that I found at a local hifi store for $30, did nothing!
A 10 meter power cord connected to the Wavebourn Edelweiss 3 Power Amp (tube headphone amp) managed to reduce the annoying "fart sounds" substantially, but this option is not very WAF. It seems any outlet at least 5 meters away from the computer is better than any USB Isolator. Sorry to burst your dream bubble!
So, you test one half-baked isolator, which is not even on our “recommended list” (thanks @staticV3
), and you then conclude that they all must not work 
staticV3
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Shocking:
No way
I retract my “half-baked” and replace with “criminally insane”
At least the specs list exactly what you get:
Nothing more, nothing less
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What?! I actually bought this in a reputable hifi store called Stereofil AS, in Oslo. In hifi there is no shame.
www.stereofil.no
Fern & Roby - nytt merke i butikken! - STEREOFIL AS
Fern & Roby er en entusiastdrevet boutique-produsent av høyttalere, platespillere og platespillertilbehør. Alle produktene lages i Richmond, Virginia og bygges med en unik blanding av håndarbeid og state-of-the-art produksjonsutstyr.
www.stereofil.no
Welcome to reality…
If the cheapest real USB isolator on aliexpress costs over 30USD, it's very unlikely a local hifi shop would have it for 30USD too.
That device does nothing to the ground wire, it just breaks the 5V line to allow external power for the USB device.
That device does nothing to the ground wire, it just breaks the 5V line to allow external power for the USB device.
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Looks like your DAC has TRRS (balanced out). I take it your speakers are powered? If they are do they have XLR? If so get a TRRS to XLR and see if CMNR cabling solves this for you.
Years ago I had an EMU 1212M PCIe sound card with 1/4 TRS outputs. To settle an argument I purposefully created TRS to XLR where I floated the shield at the output (1/4" TRS) and left if connected on the XLR (into amp). You could hear hard drive seek and reads.
When I would connect the shield pristine silence.
Years ago I had an EMU 1212M PCIe sound card with 1/4 TRS outputs. To settle an argument I purposefully created TRS to XLR where I floated the shield at the output (1/4" TRS) and left if connected on the XLR (into amp). You could hear hard drive seek and reads.
When I would connect the shield pristine silence.
The buzz is mostly a problem with headphones. I power headphones and midrange and tweeter horns with a single ended 3 watt 6N15N/6N18N/EL84 tube amp.
Bass is handled by a DIY 25W V-FET class A power amp and DIY B1 Triode preamp from Nelson Pass. I am only using 20% volume on the bass (quad of sealed Seas Excel Nextel 10") so 25W is fine for my use. I have yet to find a DAC with Sub outputs, so on my Gustard X16, I just make use of both types of outputs for biamping. One pair of outputs with normal RCA cable and one pair of outputs using a XLR to RCA adapter cable. I don't hear a difference when switching them over.
My previous Feliks Espressivo OTL headphone amp had shielding on the input caps and there was less noise with this brass shielding than after I removed it to try to upgrade the caps (see ripped brass shielding in the picture below). The new Duelund caps got lost in the post office and I sold the Feliks. It only worked good with 300 ohm headphones anyway.
In my attempts to remove the buzzing GPU "fart sounds" (the technical terminology) I have now tried to disconnect the USB cable between the Windows PC and DAC - and everything went silent, no more GPU "fart sound". But there was also no music.
The Sbooster VBus2 was snake oil and is going to be returned, as it had no effect.
The 10m power cable between headphone amp and kitchen did reduce the GPU "fart sounds" by 50%, but the cable was quickly found by wife and removed. However, it does indicate polluted ground/ground loop that starts at the GPU, and spreads to the power outlet and also via the USB cable and continues all the way to the kitchen, albeit with a diminished strength.
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Do you hear the noise in your headphones, or also in your sub? IIUC your sub amp is powered by class II power adapter - no ground loop.
The extra resistance of the power cable PE wire made more ground currents flow through your MB ground trace (the correct path), and less through your ground loop (which partly contains the audio return path between your DAC and class I tube amp).
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Also you may consider using coax cable instead of twisted pair for connecting the cinches in your class-A amp. Twisted pair is for balanced connections, for singled-ended lines the standard is a coaxial cable. It may not make any audible difference though as you have a fully shielded enclosure anyway.
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