USB Disruptor Review
I did not hear a difference when using the Schiit Yggdrasil fed by a Apple MacBook Pro, but I did hear an improvement when using a Schiit Jotunheim with the original AK4490 DAC module, fed with a Microsoft Surface Pro 4. Transients improved, making the music snappier, and the bass was less boomy - an all around upgrade. This makes sense given that the Yggdrasil has Schiit's USB Gen 5 module, while the Jotunheim only has USB Gen 2.
In the past, I had issues using my Android phone (ASUS Zenfone AR) with the iFi micro iDSD. USB Audio Player PRO generally works rather well, but using Spotify often results in stuttering and other artifacts, particularly after a song just started. Unfortunately, the USB Disruptor was not able to address this. It is probably an issue serving the actual data in a timely fashion, rather than supplying the DAC with enough power.
While generally the USB Disruptor seems to be transparent to the source device, on my phone the behavior was different with the USB Disruptor than without it, possibly because of peculiarities with USB On-The-Go (OTG). Without the USB iDisruptor, Android quickly recognizes the connected DAC and proposes launching USB Audio Player PRO, but with the USB iDisruptor this appears to take 5-10 seconds longer, to the point that I briefly thought it didn't work at all.
I wanted to see whether the USB Disruptor would fix a ground loop in conjunction with my desktop computer, but somehow that ground loop suddenly disappeared while I was establishing that it still exists without it. Not quite sure how that works, but I'm confident it would have addressed the issue as effectively as the iFi iDefender.
Comparison with the iFi iDefender + iFi iPower
In my limited testing, the USB Disruptor and the combination of iFi iDefender and iFi iPower performed the same, with the exception of the phone scenario. The iFi micro iDSD didn't always get recognized, but when it did, it got recognized quickly, while the USB Disruptor introduced a delay of 5-10 seconds before the DAC would get recognized.
The USB Disruptor cannot be used at all without a power supply connected, while the iDefender can work without a power supply if the DAC is self powered. However, it only fixed my ground loop issue when using a connected power supply, so I'm not sure what the iDefender is good for when not connected to a separate power supply. Still, it is much easier to evaluate the iDefender since connecting or disconnecting the power supply does not interrupt the USB session.
With the MacBook Pro or the Surface Pro 4 and the Schiit Yggdrasil and Schiit Jotunheim (the latter only tested with the Surface Pro 4), both devices provided the same sonic benefits with the Schiit Jotunheim and lack thereof with the Schiit Yggdrasil.
Connectivity
In terms of connectivity, the USB Disruptor has a female USB-B port for data input, and a female USB-A plug for data output, as well as female 5.5 x 2.1 mm DC barrel jack for power input. Included in the package is a an adapter with a male USB-A plug on one end and a male USB-B plug on the other. This clever combination means you can easily use the USB Disruptor on either the source end or the DAC end, in conjunction with your (presumably) existing USB-A to B cable.
The iFi iDefender has a male USB-A plug for data input and a female USB-A port for data output, making it easier to use on the source end than the DAC end. For use at the DAC end, a USB extension cord and either a regular USB A to B cable or an adapter like the one provided with the USB Disruptor need to be used. For power input, the iDefender features a Micro-USB port, allowing you to use any regular USB power supply, possibly even a USB port already present on the target device. The Micro-USB port is on the side, which means cables are sticking out the iDefender on three sides. The otherwise bulkier USB Disruptor does not have that problem, with the power coming in from the same side as the source.
The power supplies are interchangeable, using the same plug, both supplying 5 V (the usual USB voltage), though the iFi iPower can supply up to 2.5 A, while the USB Disruptor power supply is rated for 2 A. In conjunction with the iDefender, an additional adapter to micro USB is needed (included with the iPower). I could not hear a difference between the power supplies in my limited testing.
Plugged into a regular outlet, the USB Disruptor's power supply would stick out horizontally, while the iPower would stick out vertically due to the different prong orientations. Both power supplies are non-polarized and can therefore be rotated 180°. Both power supplies are rated for 100-240 V, but the iPower also comes with alternatives plugs for other countries. The iPower is a bit wider and longer, but less tall. The iPower's cable feels less fragile.
Price
The USB Disruptor costs $149 and includes a 5 V 2.0 A power supply. The iFi iDefender costs $49 and does not come with a power supply, but iFi sells the compatible iPower (5 V 2.5 A) for another $49. USB A to B adapters like the one included with the USB Disruptor are sold for less than $3 on Amazon and elsewhere. If you're concerned that these are somehow inferior to what is included with the USB Disruptor, you'll be relieved (or concerned) to know that for less than $1 Monoprice and Cableleader.com sell USB A to B adapters with what appears to be the same plastic casing as the adapter I received, although curiously not in the male-to-male configuration needed. Note that the adapter I received looked different from what is shown on the USB Disruptor page.
The power supply provided with the USB Disruptor is made by PowerStream.com, with model number MTP121UL-050200A. I did not find this particular model on their website, but the
PST-AC0520W has the same specs and costs $14.50 (less at higher quantities), while the
PST-AC0515W-2.5 has the same casing as what I received and costs $12.50 (less at higher quantities). DC to Micro-USB adapters can be had for less than $5 as well. So for about half the price of the USB Disruptor, you could get the iFi iDefender, and a comparable power supply and adapters as what is included with the USB Disruptor. Or spend a little more to get the iFi iPower, which includes many adapters for outlets around the world as well as adapter for other DC plugs, providing a more compact and versatile solution for $98 total.
Conclusion
The USB Disruptor works as advertised. But so does the iFi iDefender + iFi iPower combo for 2/3 of the price, while simultaneously being a lot more versatile and compact. As a result, I do not consider the USB Disruptor competitive at its current price of $149.