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Intona USB 3.0 Isolator Review

Music1969

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grounding noise, a $49 iFi iDefender would allow you to cut off the VBUS and feed it external power (some samsung wall wart would do), to solve the problem without having to resort to the $250+ Intona.

With what you wrote here, nothing would be done about USB ground line with iDefender... unless you are saying iDefender has been verified to isolate USB ground?

Intona isolates USB ground.
 

Atanasi

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With what you wrote here, nothing would be done about USB ground line with iDefender... unless you are saying iDefender has been verified to isolate USB ground?
IDefender detects multiple grounds, disconnects VBUS and connects to an external power supply, which is supposed to have decent isolation. It doesn't isolate data wires, so it doesn't work for everyone. Generic isolation for data wires, compatible with various devices, is orders of magnitude more complicated than just power. Make sure you have a return option if it is not satisfactory.

Intona is more comprehensive, but you can get a good balanced DAC for the same price, which may be an option. For interfacing with unbalanced it is not an option, and ADC cannot commonly use optical.
 
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Music1969

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IDefender detects multiple grounds, disconnects VBUS and connects to an external power supply, which is supposed to have decent isolation. It doesn't isolate data wires, so it doesn't work for everyone. Generic isolation for data wires, compatible with various devices, is orders of magnitude more complicated than just power. Make sure you have a return option if it is not satisfactory.
Are you saying iDefender does galvanically isolate USB ground?
 

Music1969

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No, disconnecting just the power wires from the host is not galvanic isolation.

Correct, Veri wrote:

"grounding noise, a $49 iFi iDefender would allow you to cut off the VBUS and feed it external power (some samsung wall wart would do), to solve the problem without having to resort to the $250+ Intona."

Intona isolates USB ground. That can be very advantageous (depending on system / issues).

iDefender does not isolate USB ground.
 

Veri

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Honestly if the $49 iDefender does not fix a severe ground loop issue, returning it and getting a $100 D10s for optical output and connecting that to your DAC is still a lot cheaper than going for "true" galvanic USB isolation like the Intona offers. It's pricy.
 

Final

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Intona is not cheap, but it works. I had ground loop issues and bought an IFI USB 3.0 which should brak the ground loop. Didn`t work. Embraced the suck and bought the Intona.
 

bboris77

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Intona is not cheap, but it works. I had ground loop issues and bought an IFI USB 3.0 which should brak the ground loop. Didn`t work. Embraced the suck and bought the Intona.
I have to echo this. I bought one a few months ago, plugged it in and literally forgot it exists. No fiddling with it, no dropouts, no need to plug and unplug it. It works an USB cable with ground isolation, not an USB hub. I have tried other solutions and they all had glitches and quirks that required a lot of fiddling to get them to work and even then they would only work until the PC was restarted.
 

Atanasi

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I have to echo this. I bought one a few months ago, plugged it in and literally forgot it exists. No fiddling with it, no dropouts, no need to plug and unplug it. It works an USB cable with ground isolation, not an USB hub. I have tried other solutions and they all had glitches and quirks that required a lot of fiddling to get them to work and even then they would only work until the PC was restarted.
What DAC do you use? XMOS-based products, a significant part, often have bugs with Intona, which can be fixed with a hub in between.
 

bboris77

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What DAC do you use? XMOS-based products, a significant part, often have bugs with Intona, which can be fixed with a hub in between.
I have been using the Atom DAC with it and it has been flawless. I also used the D70B for a few weeks with it, and there were no glitches. However, it was only 1-2 weeks that used it with the Intona before I sold it and downsized to the Atom DAC.
 

Armand

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Although I might sound like an Intona sales man, here are some information that I have spread and published on various places before.

- whenever you measure unbalanced, chances are big that at least one or two switched power supplies are involved (laptop, desktop, DAC, ADC...). The USB connection is the link then that ruins the measurements. Therefore I personally have 2 old Intona USB 2, one Alldaq USB 3, and one new Intona USB 2 isolator. They easily fix this kind of problem.

- there are big differences between all the available isolators. The first popular version was a chip from Analog Devices, that unfortunately only supported USB 1. That maxes out with 2 channels at 96 kHz.

Then came Silanna with a chip that was supposed to support USB 2, but seemed to be so buggy that it did not show up for several years.

In the same time (maybe a bit before, not sure) Intona started to build a USB 2 isolator discretely, by processing the input USB stream within an FPGA, transceiving the content via capacitors (galvanic decoupling) into a secondary FPGA which turns this all back into USB 2. Their solution was absolutely unique because very complicated (due to the nature of the USB 2 format), and because it operated like a wire. The operating system does not see the Intona, it does not use precious USB resources - a big advantage against all other isolators with hubs included. The Intona solution also had only a few picofarad coupling between primary and secondary ensuring perfect measurements.

Meanwhile the Silanna chip with added hub as refresher/reclocker on the secondary side (the original idea was that an additional hub chip is not needed, but that seemed not to be compatible enough) showed up in various isolators of various brands. I did not test all these. I did test the Hifime (and reported in this forum already, it completely failed with ADI-2 Pro and DAC), and the Alldaq USB 3.

In-between Corning had designed a USB 3 optical cable extension. That one is a must have if you need USB 3 in excessive lengths (there is simply no alternative), but it also has an excessive price point. Due to the simplifed nature of USB 3 format it is much easier to do capacitive coupling of the data lines (that's why suddenly several isolators showed up that can do so), but as USB 2 MUST be supported as well, Corning had to add a full USB 2 solution into a small connector (fabulous engineering work, done in Berlin ;) . It is not fully transparent (shows up as hub). The most disappointing thing here is that the cable includes two thin copper wires that deliver 5 Volt to the female end of the cable, so despite being optical it does not provide galvanic isolation! I was in contact with the developers at Corning and it seemed they simply overlooked that use case. So some people carefully cut the cable's wires and provide the 5 Volt locally to the female socket to have full galavanic isolation. Not me, though, don't want to destroy it...

- the remaining capacitive coupling in the Intonas is the lowest I have experienced. The Alldaq is less good with USB 2, which is easy to see in measurements, but works ok in USB 3.

- the price of the Intona is more than justified. It had a long development time, includes a lot of know-how, and the old unit was even expensive in parts. The newer, smaller unit (I bought it just for the better form factor and easier handling) is still expensive, but as long as there is no other mass-market chip solution that can compete I don't see why they should lower their prices. On the contrary you could say that all others using the Silanna chip had much less development effort plus lower part costs and should lower their prices...

- the Intona 5 KV version uses (really) expensive optical coupling, no way to achieve this with capacitors.

- Intona never designed these units for audiophiles. But these were the people that quickly flooded their order books, so it might be realistic to say that the smaller form factor and nicer housing is a reaction to that demand.

- as noted above I have no problems to quickly connect a few units and get heavy artefacts in my measurements. When I got my first Intona I was so happy that I sent them a measurement that they had put on their home page:

https://intona.eu/en/support/answer/1233

As you can see the effects are not just a few spikes at 50 Hz and multiples. Totally wrong harmonics and a raised noise floor. Not that this was audible (it wasn't), but who wants to spend hundreds of dollars on modern top DACs, and then get such mediocre quality to the speakers? So I can understand that people who can't measure buy this stuff just to have peace of mind.

Note: I tried the newer Intona's Aux input with a Babyface Pro, and it worked, but I didn't check the exact voltages. Will do so later.

-------------------------------
Edit: As I can still edit this post I thought it makes sense to add one correction and one information directly here.

- the voltage on the two wires of the Corning cable is 15 Volt, not 5 Volt.

- there exists an optical USB 3 cable made by Lindy with full galvanic isolation. It has a power input at the female side. I never tested it because it was not available below 30 meters length, and then was already at 300 Dollar. That was 2016, though, don't know how the current state is.

What about the ADuM4160 alternative? According to the datasheet it is USB2 compatible.
You can get them with options for external power for pennies on ebay.
https://www.ebay.com/itm/USB-Isolat...647695?hash=item42295aa44f:g:v~YAAOSw7Q1fuMFQ

1614451819105.png

https://www.analog.com/media/en/technical-documentation/data-sheets/ADuM4160.pdf
 

Matias

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mansr

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I fell in the Hi-Speed / Full-speed trap.. :facepalm:
If you find USB naming confusing, be thankful the video display people didn't get to decide. They would have called it something like this:
  • 1.5 Mbps: Standard Speed
  • 12 Mbps: High-Speed Ready
  • 480 Mbps: Full High-Speed
  • 5 Gbps: Ultra-High Speed
The 10 Gbps speed would come in three mutually incompatible variants: High Data Rate (HDR10), Dolby® Data, and Hybrid Link Bus.
 

Lambda

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USB naming confusing,

USB3.2 gen2 10gbit QC 2.1 PD65W ready with thunderbolt 2.1 2x16 pcie4 and display port up to 4K HDR10

be thankful the video display people didn't get to decide
Or (micro)SD card manufactures

Extreme
Extreme Pro
Ultra
Ultra Pro
Evo
Evo+
Evo select
High endurance

I fell in the Hi-Speed / Full-speed trap.. :facepalm:
same happened to me.
 

chris719

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A fair review. Appreciate the work. The price of this thing though is still a bit too high.

I’m not sure. It’s not that simple to isolate HS or SS USB. You can’t normally isolate the USB physical layer for a few reasons, so at minimum these solutions probably have to isolate ULPI and PIPE3 interfaces coming out of a PHY. I’ve seen FPGAs on both sides of isolators like this targeting other industries like medical, so it may require state management or something more complicated than just deserialization and isolation.

As MC mentioned, the SS data pair isn’t hard to isolate and you can achieve that through caps or a pulse transformer most likely, but the HS D+ and D- are problematic because they aren’t always a true differential pair or DC balanced.
 
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mansr

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I’m not sure. It’s not that simple to isolate HS or SS USB. You can’t normally isolate the USB physical layer for a few reasons, so at minimum these solutions probably have to isolate ULPI and PIPE3 interfaces coming out of a PHY. I’ve seen FPGAs on both sides of isolators like this targeting other industries like medical, so it may require state management or something more complicated than just deserialization and isolation.

As MC mentioned, the SS data pair isn’t hard to isolate and you can achieve that through caps or a pulse transformer most likely, but the HS D+ and D- are problematic because they aren’t always a true differential pair or DC balanced.
Right. The SS signals are already capacitor coupled and unidirectional, so the challenge in isolating those is only the speed. The D+/D- pair is tricky since device detection and speed selection is done by pulling one or the other high. Some states are also signalled by driving both data lines high or low. Isolating this requires sensing all possible states on one side of the barrier, communicating it by some other method, and then recreating the correct state on the far side.
 

chris719

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Right. The SS signals are already capacitor coupled and unidirectional, so the challenge in isolating those is only the speed. The D+/D- pair is tricky since device detection and speed selection is done by pulling one or the other high. Some states are also signalled by driving both data lines high or low. Isolating this requires sensing all possible states on one side of the barrier, communicating it by some other method, and then recreating the correct state on the far side.

Yeah, the SS pair is already AC coupled but it’s typically with tiny caps that have a 50-250V voltage rating. You’d want something else to satisfy a typical galvanic isolation requirement.
 

MC_RME

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Well, looks like the Silanna chip without reclocking/buffer. Then it's typically not much compatible/reliable.
 
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