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Topping E30 powersupply/USB noise

OP
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CTheCurious

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most likely. It is all in your head ;)
But if not you can measure it wit REW or something and show us...

You can try grounding the USB hub "Ground".

But over all very disappointing to hear another "high end" product being so susceptible to noise from the USB port.
And also sad There is no testing for this USB port "isolation" in the reviews.

No one hears the difference between SINAD of 115 and 120dB but this problem is kind of obvious and annoying for many customers.
Yet it would be very easy and cheap for the manufacturer to make the DAC (mostly) immune to noise form the usb port.

Selling an Separate USB isolator is a strange after thought.
This could and shuld be included in the devices for cents.





The same Conclusion he had for USB isolatos
and for cables...
don't know how he can make this conclusion if he was not able to reproduce the problem many experience.

You don't need an "linear" power supply You need an Low noise power supply with low common mode capacitance or High impedance.
It just happens to be many linear power supply's are low noise and have high impedance to mains.

As OP is experiencing the DAC is clearly not doing well with noise coming from the USB port.
A USB Isolator with an Low noise power supply would help.

Better RCA cables would maybe Help.

Are the USB ports properly grounded to the PC case? is this a DIY pc or from a big manufacturer (who actually dose EM compliance testing)

Nice argumentation, the usb ports were on a basic usb hub powered by a DC powersupply, so I don't think i can do much there, I think I could try to ground the PC USBs and connect the dac to them. I changed the powersupply to a phone chargher and connected the toslink, the noise isn't there at all, so now I just have to check the USB.
 
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half_dog

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I think the problem has a simple solution and it doesn't include more grounding paths. Sometimes when you have some devices connected between them and each one is grounded using their own power plug this can cause ground loop.
Configuration:
I plugged my DAC to 2 USB, obviously 1 for power and 1 for data, on a USB hub that has it's own powersupply and is connected to my PC. The output of the E30 goes to a DarkVoice 336S.
In this case I believe your desktop and Darkvoice are grounded and E30 with the USB HUB are in between this chain. It's not rare in to get noise in this situation and a simple solution is to float one of the ground connections - exactly what A30 Pro does. Using a plug adapter which has no ground pin you can lift off DarkVoice leaving it "floating". In reality it won't be because (in this specific scenario) it will be grounded by the rest of the chain (pc>USB HUB>E30>DarkVoice). When you use optical connection and a power supply like a phone charger or a powerbank, the only equipment which is grounded is the amplifier, hence there is no ground loop.
Sorry if I didn't explain well, I'm not a native English speaker.
 
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CTheCurious

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I think the problem has a simple solution and it doesn't include more grounding paths. Sometimes when you have some devices connected between them and each one is grounded using their own power plug this can cause ground loop.

In this case I believe your desktop and Darkvoice are grounded and E30 with the USB HUB are in between this chain. It's not rare in to get noise in this situation and a simple solution is to float one of the ground connections - exactly what A30 Pro does. Using a plug adapter which has no ground pin you can lift off DarkVoice leaving it "floating". In reality it won't be because (in this specific scenario) it will be grounded by the rest of the chain (pc>USB HUB>E30>DarkVoice). When you use optical connection and a power supply like a phone charger or a powerbank, the only equipment which is grounded is the amplifier, hence there is no ground loop.
Sorry if I didn't explain well, I'm not a native English speaker.
Yup, I guess that is a good point too. Since the 2 circuits, the PC and the Amp, were interconnected with each other, passing by the DAC first, the loop would be interrupted if one of the grounds is removed.

In fact the reason why I don't have a loop noise, now that I plugged the phone charger and the toslink, is because the DAC doesn't connect the 2 circuits grounds anymore.

So remove the ground from 1 circuit should be a possible solution, yet it can be dangerous for the device.
 

half_dog

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So remove the ground from 1 circuit should be a possible solution, yet it can be dangerous for the device.
Yep! I think it's not a big deal for DarkVoice because it will be grounded by E30's RCAs (supposing it being connected via USB). Amps like L30, Atom etc which have no ground pin work this way... Their ground reference are on the equipment up them at the audio chain.
 

fritobugger

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On a somewhat related note, if someone owns the SMSL P2 Linear Power Supply, it works with the E30 on port 2 set to 5V
 

Purified_Water

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JayGilb

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Purified_Water

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Many of the lower priced isolation transformers will roll off bass frequencies.
Thanks for pointing that out. I had some time to compare between having the ground loop isolator and not. The isolator ends up killing all of the sub bass on my headphones.
 
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