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RME User Forum → ADI-2 & 2/4 Pro series, ADI-2 DAC series → Topping HS02 USB2.0 Audio Isolator
Hi,
Has anyone got experience of using an USB isolator please?
I stream from my laptop to the ADI-2 DAC and wonder if there's any benefit in isolating noise from the laptop?
Thanks
Don
Is there noise from the laptop?
Not that I'm aware of, but I suppose an improvement is possible?
The general option I've heard on audio forums is that a computer is a poor source.
I suppose I'm trying to get real world evidence that whether this is a problem and if this isolator or similar would potentially lower the noise floor, "a blacker background" 
If you don't hear any noise, then there is nothing to improve.
Not that I'm aware of, but I suppose an improvement is possible?
The general option I've heard on audio forums is that a computer is a poor source.
I suppose I'm trying to get real world evidence that whether this is a problem and if this isolator or similar would potentially lower the noise floor, "a blacker background"
ADI-2 itself does not benefit from an USB Isolator, no matter how polluted the USB bus might be.
It’s constructed it in a way that this type of disturbance stays out, literally.
This includes headphones directly plugged into it.
What can make a difference under certain circumstances is equipment connected further down, like a power amp or active speakers.
If they exhibit “computer noise” - this is the real world evidence you’re looking for - an USB Isolator can solve that.
The common downside of USB Isolators is:
As they isolate the USB ground/shield interconnect, there is the chance that high enough voltages between devices can built up to kill the USB interfaces of both ADI-2 and the computer.
Specifically plugging / unplugging USB is most critical.
So if there is nothing to solve, don’t buy yourself into trouble.
BTW: I wouldn’t give a penny on the “common knowledge” distributed in audiophile forums.
The stock ADI-2 2-prong PSU will generate a static noise on the ground if the device isn't grounded through USB. Audible and annoying with iems, but that would advocate against using an isolator.
MC himself praises the Intona isolators here:
https://audiosciencereview.com/forum/in … ost-339078
A ground loop could theoretically form if the RME PSU is plugged into an outlet with a different ground potential than the laptop, but then plugging both in the same outlet is a much easier fix.
The common downside of USB Isolators is:
As they isolate the USB ground/shield interconnect, there is the chance that high enough voltages between devices can built up to kill the USB interfaces of both ADI-2 and the computer.
Specifically plugging / unplugging USB is most critical.
This statement is only valid for the very cheap isolators that just cut ground/shield and +5 V. Real isolators do not cause this kind of issue.
Many thanks for all the replies to my question.
I don't think that an isolator is needed in my system, as there's no static noise or ground loop problem.
Kind regards
Don
KaiS wrote:The common downside of USB Isolators is:
As they isolate the USB ground/shield interconnect, there is the chance that high enough voltages between devices can built up to kill the USB interfaces of both ADI-2 and the computer.
Specifically plugging / unplugging USB is most critical.This statement is only valid for the very cheap isolators that just cut ground/shield and +5 V. Real isolators do not cause this kind of issue.
How to find out which one is “real”?
MC wrote:KaiS wrote:The common downside of USB Isolators is:
As they isolate the USB ground/shield interconnect, there is the chance that high enough voltages between devices can built up to kill the USB interfaces of both ADI-2 and the computer.
Specifically plugging / unplugging USB is most critical.This statement is only valid for the very cheap isolators that just cut ground/shield and +5 V. Real isolators do not cause this kind of issue.
How to find out which one is “real”?
Tests by people that know what they are talking about?
KaiS wrote:MC wrote:This statement is only valid for the very cheap isolators that just cut ground/shield and +5 V. Real isolators do not cause this kind of issue.
How to find out which one is “real”?
Tests by people that know what they are talking about?
Who should that be and where to find them?
@MC / Matthias Carstens does at least have some insight and more than enough technical knowledge.
But would he - or someone else - give a warranty?
Don’t get me wrong:
I just want to vote for not easily plug an isolator just because having read some random forum claims about audio quality improvements.
An USB Isolator is a tool that can solve exactly one problem:
Break hum loops caused from double grounding, source and destination.
But good ones cost a penny.
Even the better ones have their problems, read the numerous reviews about fried audio cards and interfaces, just an example:
https://www.amazon.de/gp/customer-revie … B0849J33T9
The ifi Defender is the exact kind of GND cut-off isolator that can destroy USB inputs, and I pointed that out several times already. A real galvanic isolator - also pointed out earlier - these days starts below 40 bucks - and works and doesn't destroy anything.
Since Analog Devices and TI started shipping their new isolator chips capable of true USB 2.0 High Speed performance last year, prices have gone down significantly. This unit for example had cost 39 bucks only:
https://www.amazon.de/gp/product/B0CSYNSZ3K/
Same as this one:
https://www.amazon.com/DSD-TECH-SH-G01B … 0CBJYGBL3/
The Hifime isolator I mentioned several times as well:
https://hifimediy.com/product/hifime-hi … olator-v2/
then the Topping HS02, the Cesys ISO-U20 and so on. Lots of working solutions available far below the former 'at least 200 bucks' price range.
EDIT
The chips used are
Analog Devices: ADUM3165, 3166, 4165, 4166. The old version without 480 mbps mode is ADUM3160 and 4160. AD here surely did a bad job in naming them so they can be easily identified and not confused with the former versions.
Texas Instruments: ISOUSB211. The old version without 480 mbps mode is ISOUSB111.
Both chips have been tested at RME and work a treat. Completely transparent (not detected as device), no drivers, just insert them into the USB path.
The effective amount of reducing leakage current and ground loop effects is given by the coupling capacity between USB 'input' and 'output', in pF (picofarad). While the chips itself stay far below 10 pF, the layout of the PCB, but even more the typically added power module (to transport input power to the output galvanically isolated) can add significant capacity. For example the Topping HS02 has 1 nF (1000 pF) coupling capacity due to the included Mornsun DC/DC converter, making it not suitable for laboratoy measurement tasks.
That’s good news/info, I’ll keep this posting bookmarked for later reference.
Added some more details to post #12.
Extremely helpful! Thank you very much.
Added some more details to post #12.
Thank you for this information.
RME User Forum → ADI-2 & 2/4 Pro series, ADI-2 DAC series → Topping HS02 USB2.0 Audio Isolator
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