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.
