Neutron HiFi Isolator V1 | High-speed USB data & power isolator

[dmitrykos]

Neutron HiFi Isolator V1 was just released and is available for ordering, so sharing details about it in this dedicated thread.

Device is very useful for audiophile community as a noise eliminator on USB power (VBUS) and data paths in case you are listening to music via DAC or DAP connected to PC, or powered via non-isolated power source.

Due to galvanic nature Isolator V1 removes ground-loop noise, as well as other noise sources making audio spectrum very clean. Below is spectrogram (made with Audacity) of the silence playback by one of popular DAPs when DAP is connected to PC with USB cable. You can observe a lot of noise sources spread all over the audio spectrum in the Line-out of the DAP:

Here is spectrogram of the silence playback when the same DAP is connected to PC via Isolator V1, as you can see all above seen noise sources are gone and spectrogram looks clean:

In order to reconfirm this performance the silence playback was measured with DAP running on its battery (always clean power source) only and results show that spectrogram is the same clean and looks similar as for the case when DAP was connected to PC via Isolator V1:

What do these measurements say? Isolator V1 provides similar to on-board battery clean power source obtained from USB port of PC (usually always noisy). If you are looking for a clean sound, free from humming, pops & clicks, on its silent parts and do not want to waste the battery of the DAP then Isolator V1 will be a handy intermediary device between USB power/data source and your connected audio equipment.

This example was provided for a DAP usage scenario but of course DACs will benefit similarly. If your USB DAC or DAP has built-in circuit for data and power isolation then Isolator V1 will not make audio spectrum cleaner but on the other hand it will act as electric surge protector for your valuable device - it is much cheaper to replace burnt Isolator V1 then repair burnt power circuit of the DAC, DAP, ...

There was a preceding discussion in Neutron HiFi DAC V1 thread already about it, so you could have a look if interested in other details, especially in relation to Parasitic capacitance (kindly raised by @MC_RME), which is very low for Isolator V1 and is on the level of 20-22pF.

Specification and User manual are provided on Neutron HiFi web site in the Details section and more details are on the Product page.

Device is USB 2.0 compliant, therefore it handles High-speed, Full-speed, down to Low-speed USB data transfers. For the audio community High-speed and Full-speed USB communication is the point of interest. Isolator V1 was tested with popular DAPs and DACs, including of course Neutron HiFi DAC V1, and results confirmed its correct operation in all usage scenarios. High-speed data transfer support means - USB Audio 2.0 support with PCM up to 1,536 Mhz or higher (latest max for DAPs) and DSD1024 or higher.

Isolator V1 features high-precision highly-stable external Crystal oscillator circuit which aids internal IC in re-clocking USB data, therefore if your USB DAC or DAP has issues with USB data packets, Isolator V1 can be a helpful tool to heal USB data on its way to your audio device, in addition to noise elimination on the data path.

Galvanic nature of Isolator V1 helps to protect your valuable and often expensive audio equipment from electric surge coming via USB power (VBUS) and data paths.

Isolator V1 will deliver max 400 mA to your audio device harvested from the USB source port and therefore if your device needs more power - there is a Micro-B socket for external 5V power which you can provide from another isolated power source, like mobile phone charger (but not from PC as you will inject power noise via it!).

Device is ultra small - 40.3 x 22.3 x 20 mm (L x W x H) only, therefore it is very portable and can be used on the go, for example if you power your DAC or DAP during a flight (nobody knows how correctly USB outlet works in your seat). It is IP67-rated device (passed IP certification), therefore it can withstand operation in a harsh environment. Enclosure is made from Aluminium alloy and is fully metallic inside, on the sides panels are made from Gorilla Glass 3 material (just like the display area of Neutron HiFi DAC V1) that adds a high degree of durability by making USB socket area less prone to scratching and, of course - they look and feel just great!

Any questions, please post here and I will be glad to clarify in more detail.

 

[dmitrykos]

Posted explanatory video related to audio noise caused by the noise picked from the USB connection:

Details of the tests are in description of the video.

 

[NickArcade]

What digital isolator module is being used inside the Isolator V1?

 

[dmitrykos]

What digital isolator module is being used inside the Isolator V1?

ADUM4166

 

[audio_tony]

Isolator V1 provides similar to on-board battery clean power source obtained from USB port of PC (usually always noisy).

It's very rare to encounter a noisy USB port these days, so your statement that USB ports are "usually always noisy" is misleading.

Ground loops do however still cause issues.

 

[antcollinet]

It's very rare to encounter a noisy USB port these days, so your statement that USB ports are "usually always noisy" is misleading.

Ground loops do however still cause issues.

In that PC ground is normally (or at least often) noisy - and PC ground is connected to USB ground, hence providing noise currents into ground loops - I don't find the statement misleading.

 

[audio_tony]

In that PC ground is normally (or at least often) noisy - and PC ground is connected to USB ground, hence providing noise currents into ground loops - I don't find the statement misleading.

Hence my statement about ground loops still causing issues. However the power source for the USB ports is not inherently noisy.

If there is no ground loop present, then there is no noise issue from "noisy USB ports".

The OP's statement is misleading.

A few years ago, I did some tests on USB ports and found no noise issues, apart from when a ground loop was present.

I even injected a separate low noise DC source and this made no difference. Go figure...

USB noise measurements

USB noise measurements

gtkc.net

 

[antcollinet]

However the power source for the USB ports is not inherently noisy.

Agreed.

A few years ago, I did some tests on USB ports and found no noise issues, apart from when a ground loop was present.

However, peoples perception (especially those without a detailed electronic understanding) is they hear noise when connecting to PC audio - normally via USB. The assumption often made is "noisy USB port" and actually they are correct. It is just that it is not the USB power that is noisy - it is the USB (along with the rest of the PC) ground.

It is precisely this noise that the isolator device is designed to tackle. So the statement made is not unreasonable - especially when addressed to lay people who neither know nor care if they are hearing USB power noise, or USB ground noise via ground loops.

 

[DSJR]

It costs more than my dac though - sorry to be a sour-puss here...

 

[audio_tony]

However, peoples perception (especially those without a detailed electronic understanding) is they hear noise when connecting to PC audio - normally via USB. The assumption often made is "noisy USB port" and actually they are correct. It is just that it is not the USB power that is noisy - it is the USB (along with the rest of the PC) ground.

It is precisely this noise that the isolator device is designed to tackle. So the statement made is not unreasonable - especially when addressed to lay people who neither know nor care if they are hearing USB power noise, or USB ground noise via ground loops.

The OP stated:

"Isolator V1 provides similar to on-board battery clean power source obtained from USB port of PC (usually always noisy)."

They are implying that the power source is noisy.

All the OP had to say was that the device eliminates the possibility of ground loops, and the noise that ground loops cause.

Because without an isolator, but with a "clean" power source (whether that be battery etc.) a ground loop can still be present.

I stand by my claim that the OPs statement is misleading.

 

[dmitrykos]

They are implying that the power source is noisy.

It is actually true and confirmed by measurements. VBUS of USB port can be quite noisy. If USB DAC or any other USB device has weak circuit design related to power then it can be a problem for a device, at least for audio device it can result in analog noise on Line-Out.

Here are 3 variants of measured noisy VBUS (marked as AO_5V) where you can see the result of operation of some switching device (inside PC) causing voltage spikes (noise), the voltage is also fluctuating (see the waves):



Here is VBUS of Neutron HiFi Isolator V1 at different loads with double magnification of the plot measured on the same machine and USB port. You can see that power noise after Neutron HiFi Isolator V1 device (on its USB-C output) is considerably low and signal is very clean, without switching artifacts of USB host:



Therefore earlier statement which you quoted is supported by actual measurements and results. Clean power/VBUS harvested/generated by Isolator V1 is just one of the benefits (but not major).

Of course, the main feature of USB isolator is galvanic isolation which disconnects grounds of connected devices and thus eliminates the ground loop noise (as a consequence) which in audio device can be really distinguishable, especially when listening with external speakers.

While VBUS noise (demonstrated above) can still be eliminated with a correctly designed circuit the noise caused by ground loop can not be eliminated reliably without isolation. Isolation can be internal (for example USB DAC's circuit uses similar USB isolating circuit) or external (for example USB DAC is connected to PC via USB isolator). Ground loop noise is quite strong and affects analog audio considerably on different frequency bands.

Log scale:


Linear scale:

 

[192kbps]

Have you tested the latency?

 

[antcollinet]

Have you tested the latency?

There should be no additional latency with this type of product. It is simply repeating the USB signals through an isolation device. There are no buffers involved.

 

[trl]

I did some USB measurements myself too a few years back (posted by @Archimago here: https://archimago.blogspot.com/2018/05/measurements-computer-usb-5v-power.html). If I'll ever buy such an isolator I'll such measurements again to compare with vs. without the isolator. Thank for the view @dmitrykos.

 

[dmitrykos]

Linking the review of Isolator V1 to this thread:

JDS Synapse & Neutron V1 USB Isolators Review

This is a review and detailed measurements of the JDS Labs Synapse and Neutron Hifi V1 USB isolators. They were both sends to me by the respected companies. Synapse costs US $69, and Neutron US $118. As you see, the styles are very different. Synapse comes in a playful red color. Neutron in a...

www.audiosciencereview.com

It is featuring a useful discussion about ground loop noise problem.