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Any solution to avoid PC interferance?

March Audio

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#21
Quite likely, although you need to power the toneboard from a different USB supply (try just a phone charger) than the PC
I am replying to myself, must be going mad.

Just wanted to edit the above as I wasn't paying attention. An optical spdif would provide isolation. Electrical spdif wouldn't. The toneboard is electrical so not a solution in this instance.
 
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#22
I had a lot of USB noise from my Mac mini 2012.
And maybe also EMI noise, and ground issues from the outlets in the house.
The tube amp was picking but vibrations of my 4-drive NAS
My Oppo portable amp was a pass through of the usb noise.
It was a nightmare

I did many things to try to fix:
- one way was to use a raspberry pi as a Dlna receiver, connected via WiFi. That works great but may not suit you.
- used a better cable to the tube amp, coax with shielding etc... works quite well for EMI bit not perfect.
- I’ve tried the iFi defender 3. Works well enough with an external Power supply but not perfect. Without a power supply it reduces some of the noise but it’s not sufficient.
- I have a powered USB. Doesn’t help completely.
- I have a dedicated lower tier Furman power strip for the audio gear. Seems to help a bit.
- the most dramatic change and now my solution was to change the DAC. I have a SMSL SU-8 v2. It removes all noises.
Most likely thanks to its good power supply plugged to the furman. The Oppo lets the USB 5V go through without filtering it seems. It doesn’t use its battery if plugged to the computer. Or something...

I am a happy camper like that. Didn’t have to change the Mac mini.

Maybe you can extract something from my experience.
 

March Audio

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#23
@March Audio

And are you sure an USB isolator would solve my problem? I just contacted Ciúnas Audio about their USB isolator (assuming it's an USB isolator like the Intona) and his answer was:
"No it won't solve your ground loop problem - I don't isolate the ground, I isolate the USB data lines themselves as this is how excellence in sound is achieved. You should solve the ground loop separately. Sorry, I can't be of much help but I have struggled with ground loop issues in Italy before & am afraid it was a nightmare"

I am not sure about what he means by that and if it would apply to all USB isolators.

What do you think?
Well I wouldn't provide a guarantee ;) but it's very likely. There is a way to test this to be sure, but I am uncomfortable relating it for safety reasons.

I am not famiar with the Cuinas product, but it sounds just like a USB hub. It's clearly not an isolator. Speaking generally not specifically about the Cunas, there are unfortunately many "USB cleaning" products out there that do nothing useful.

The specific thing you are looking for is galvanic isolation. The intona completely isolates the data lines, power lines and ground.
 
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Nobunaga
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Thread Starter #24
Well I wouldn't provide a guarantee ;) but it's very likely. There is a way to test this to be sure, but I am uncomfortable relating it for safety reasons.

I am not famiar with the Cuinas product, but it sounds just like a USB hub. It's clearly not an isolator. Speaking generally not specifically about the Cunas, there are unfortunately many "USB cleaning" products out there that do nothing useful.

The specific thing you are looking for is galvanic isolation. The intona completely isolates the data lines, power lines and ground.
Now that you mention it, i don't see galvanic isolation for the Quinas.

I have to admit that i am not a big fan of the Intona, it looks butt ugly and it's a bad bang for the buck. True, that it measured well in the tests and about others we don't know.

For instance, i found this one https://www.delock.de/produkt/62982/merkmale.html which offer 3x higher galvanic insolation and costs 100USD less

Or this one here for the same price as the Intona https://shop.alldaq.com/Schnittstel...143382.html?MODsid=k5grhvgmm9v9dlr8hhempssmr1 but offers USB 3.0

What do you guys think about these two?
 
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digitalfrost

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#25
Looks like a classic "ground loop" issue to me. The PC is earth-grounded which means USB gound is at earth potential, and your tube amp also is earthed which means audio ground is earth ground, therfore theses grounds are connected two-fold, one time via the RCA cable shield and one time via the protective earth connections.
In the old times, most amplifiers were Class II appliances, meaning they did not have a wired safety ground. I've ran 2-pin amplifiers for a very long time via unbalanced connections from my PC. But more and more amplifiers that you can buy today use the dreaded 3-pin connection.

I've added a digital interface to my PC, from there I go into DACs via SPDIF, the DACs themselves only have 2-pin et voila, everything is fine again. A lot of effort to fix something that wasn't really broken. That said, unbalanced connections are such bullshit, especially in times where computers are ever more prevalent.
 

March Audio

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#26
Now that you mention it, i don't see galvanic isolation for the Quinas.

I have to admit that i am not a big fan of the Intona, it looks butt ugly and it's a bad bang for the buck. True, that it measured well in the tests and about others we don't know.

For instance, i found this one https://www.delock.de/produkt/62982/merkmale.html which offer 3x higher galvanic insolation and costs 100USD less

Or this one here for the same price as the Intona https://shop.alldaq.com/Schnittstel...143382.html?MODsid=k5grhvgmm9v9dlr8hhempssmr1 but offers USB 3.0

What do you guys think about these two?
They both look like they should do the job
 
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#27
The cheap $10 ebay usb isolator worked perfect for me, the only downside is it drops the USB speed down and the DAC will max out around 96khz, however it is totally clean now noise wise which is better. It looks like the iFi iDefender does the same thing but does USB 3.0 speeds, will have to try it out sometime as it's not too crazy at $50.
 

KSTR

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#28
In the old times, most amplifiers were Class II appliances, meaning they did not have a wired safety ground. I've ran 2-pin amplifiers for a very long time via unbalanced connections from my PC. But more and more amplifiers that you can buy today use the dreaded 3-pin connection.
Now, even with all Class-II gear you can run into ground loop issues when the balancing currents are significant, which is the the case with pretty much all switch-mode power supplies.
 
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