Enhancing USB Audio: My Experience with ADUM3160 USB Isolator on WiiM Ultra

[vbutani]

I recently conducted an experiment with my setup that yielded noticeable improvements.

Since the WiiM Ultra has only one USB port, I use a TP-Link USB hub to connect both my USB drive and a DDC. Although my DDC already features galvanic isolation, I wanted to see if I could further reduce noise introduced by the USB hub and hard drive before it reaches the DDC.

After researching online, I discovered a USB voltage isolator based on the ADUM3160/4160 chip, designed to provide electrical isolation between USB ports.

Given that my DDC already incorporates galvanic isolation, I wasn’t expecting much improvement, but since the device cost only around $10, I decided to give it a shot. To my surprise, the results were remarkable. It further reduced noise, leading to an even wider soundstage, tighter and more controlled bass, and a refined overall presentation.

For anyone using USB as an input in their system, I recommend trying a USB isolator. It’s a simple and cost-effective tweak that can make a meaningful difference!

 

[Pragmatist]

 

[F1 Fan]

I recently conducted an experiment with my setup that yielded noticeable improvements.

Since the WiiM Ultra has only one USB port, I use a TP-Link USB hub to connect both my USB drive and a DDC. Although my DDC already features galvanic isolation, I wanted to see if I could further reduce noise introduced by the USB hub and hard drive before it reaches the DDC.

After researching online, I discovered a USB voltage isolator based on the ADUM3160/4160 chip, designed to provide electrical isolation between USB ports.

Given that my DDC already incorporates galvanic isolation, I wasn’t expecting much improvement, but since the device cost only around $10, I decided to give it a shot. To my surprise, the results were remarkable. It further reduced noise, leading to an even wider soundstage, tighter and more controlled bass, and a refined overall presentation.

For anyone using USB as an input in their system, I recommend trying a USB isolator. It’s a simple and cost-effective tweak that can make a meaningful difference!

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Difference in what way?

 

[HansD-NL]

"It further reduced noise, leading to an even wider soundstage, tighter and more controlled bass, and a refined overall presentation." --> These remarks are straight out of a (any) hifi magazine, this flowery language is used over and over again.

 

[vbutani]

"It further reduced noise, leading to an even wider soundstage, tighter and more controlled bass, and a refined overall presentation." --> These remarks are straight out of a (any) hifi magazine, this flowery language is used over and over again.

Thank you for the compliment—feels like my post could make it to a hi-fi magazine!

On a more factual note, I did a blind test with this setup, and even my teenage son, who has no technical background, noticed the difference. Without knowing any details, he described the improvements in his own words: “It feels like music is around me, the bass drum lasts longer, and the sound feels more lively, while the previous sound was flat and straight.”

To add some context, my environment might contribute to the noise issues—there’s a power extension board and plenty of wiring around my AVR and HT setup, which could be causing interference. So, this isolator might be addressing issues specific to my setup.

That said, after upgrading from WiiM Pro to Ultra, I felt the soundstage wasn’t as wide as before. Adding this isolator brought it back, which I suspect might be due to noise from the USB hub or drive, not the Ultra itself.

It’s also possible that my system is now revealing more detail than before because of previous upgrades, like changing speakers, amp, and speaker cables. Before these changes, I couldn’t perceive such subtle differences.

At the end of the day, it’s up to you all. I just wanted to share my experience since this tweak was cost-effective and made a meaningful improvement in my system.

 

[robtw62]

I can confirm this suggestion works. Based on this thread I bought https://www.amazon.com.au/DSD-TECH-SH-G01B-Isolator-High-Speed/dp/B0CBJYGBL3 for $34.99 and am back using USB to connect the Wiim Ultra to Fiio K11 R2R.

Before doing this I had changed to using S/PDIF due to the buzz I was experiencing from the USB connection.

The USB connection now has a lower noise floor than the S/PDIF connection had.

I can also confirm that my highest resolution songs are still playing at their correct bit-rate too.

 

[robtw62]

Just a quick correction to my previous post above:
I've noticed that the USB isolator appears to have reduced the noise floor when using either USB or S/PDIF compared to before using it.

At the moment both are equally quiet and I'll devote some time to determining which is better in my system, if there is any difference.

My understanding is that the USB connection is technically better from a spec perspective.

 

[Griff]

The FiiO K11 R2R supports a 96kHz/24-bit for optical input. It also supports up to 384kHz/32bit via USB. In practice you probably would not notice any difference but usb would have the advantage to just set everything to max, leave it there and not worry about sample rates again. Up to you really. Good job with the isolator. I have a couple for the same reason you do.

 

[harkpabst]

I've noticed that the USB isolator appears to have reduced the noise floor when using either USB or S/PDIF compared to before using it.

At the moment both are equally quiet and I'll devote some time to determining which is better in my system, if there is any difference.

If the isolator removes pops and clicks, it's certainly worth the modest expense in this context.

But how do you evaluate the lower noise floor? I hope, it's not "by ear"?

 

[robtw62]

The USB connection still has 2 low level pops between songs that I've learnt to live with whereas the S/PDIF connection doesn't.

Without the USB isolator the noise floor I'm referring to is that annoying buzz I was experiencing prior to using the USB isolator.

With the isolator I can't hear any such noise and that is good enough for me.

 

[HansD-NL]

The USB connection still has 2 low level pops between songs that I've learnt to live with whereas the S/PDIF connection doesn't.

Without the USB isolator the noise floor I'm referring to is that annoying buzz I was experiencing prior to using the USB isolator.

With the isolator I can't hear any such noise and that is good enough for me.

"The USB connection still has 2 low level pops between songs that I've learnt to live with whereas the S/PDIF connection doesn't." --> Is that only happening when those 2 songs are different resolutions (bit-depth/samplerate)?

"Without the USB isolator the noise floor I'm referring to is that annoying buzz I was experiencing prior to using the USB isolator." --> That sounds like a ground loop and is in your case fixed by the isolator, which is great.

 

[adias]

The USB connection still has 2 low level pops between songs that I've learnt to live with whereas the S/PDIF connection doesn't.

Without the USB isolator the noise floor I'm referring to is that annoying buzz I was experiencing prior to using the USB isolator.

With the isolator I can't hear any such noise and that is good enough for me.

Never heard pops between tracks. USB isolator? Maybe for certain DACs but for DACs with excellent USB ports I do not think it’s necessary. I use a Ultra connected to Schiit Audio Unison USB ports and hear no pops or noise - perfect silent background. USB out only makes sense if the DAC port and stream regeneration are top notch.

 

[robtw62]

Good to know. Thanks for this info.

 

[slartibartfast]

The USB connection still has 2 low level pops between songs that I've learnt to live with whereas the S/PDIF connection doesn't.

Without the USB isolator the noise floor I'm referring to is that annoying buzz I was experiencing prior to using the USB isolator.

With the isolator I can't hear any such noise and that is good enough for me.

You said the SPDIF had a lower noise floor as well. When I turn volume to maximum I don't hear anything so how would you know?

 

[robtw62]

I said: "With the isolator I can't hear any such noise and that is good enough for me"

 

[slartibartfast]

I said: "With the isolator I can't hear any such noise and that is good enough for me"

That was on USB wasn't it not SPDIF?

 

[robtw62]

At first I only tested the USB connection after adding the USB isolator to the connection.

I mentioned at that point the USB connection was now quieter than the S/PDIF (the S/PDIF before the USB isolator was added).

When I eventually got to test the S/PDIF connection (I have both connection options) with the USB isolator now in place for the USB connection, I realised the S/PDIF connection was even quieter than it had been before I added the USB isolator.

 

[slartibartfast]

At first I only tested the USB connection after adding the USB isolator to the connection.

I mentioned at that point the USB connection was now quieter than the S/PDIF (the S/PDIF before the USB isolator was added).

When I eventually got to test the S/PDIF connection (I have both connection options) with the USB isolator now in place for the USB connection, I realised the S/PDIF connection was even quieter than it had been before I added the USB isolator.

OK I am just surprised you can hear the lower noise floor, I hear nothing with my ear to the speaker at max volume.

 

[robtw62]

I think we’re actually in complete agreement.

– Like you, when I listen at full volume with my ear to the speaker after installing the isolator, I hear absolutely nothing using Wiim DAC or Fiio DAC via USB or S/PDIF.
– Prior to that, even at low listening levels the buzz was there and very annoying when using either the Wiim DAC or the Fiio DAC via USB - the isolator eliminated the buzz entirely for both.

Bottom line: your experience of silence at max volume mirrors mine. The isolator solved the issue 100%, and best of all, it’s a very cost-effective solution. Hopefully that helps others chasing a similar buzz.

 

[vbutani]

Maybe for certain DACs but for DACs with excellent USB ports I do not think it’s necessary.

If noise is present in the chain, even high-quality DDCs or DACs may struggle to perform at their best. In my setup, I use a Singxer SU-1 DDC paired with a Musician Pegasus R2R DAC via an I2S connection. I initially shared your impression that a USB isolator wouldn’t make a noticeable difference—but to my surprise, it did.