Review : Kanex KTU10 Thunderbolt to USB 3.0 and eSATA

Small adapter brings USB 3.0, eSATA to Thunderbolt computers

MacNN Rating:


Product Manufacturer: Kanex

Price: $80

The Good

  • USB 3.0 for 2011 Macs
  • Price
  • eSATA for OS X
  • Windows compatibility

The Bad

  • Stumpy Thunderbolt cable
  • Reported durability problems
Apple has never been shy about funky ports -- first it was Apple Desktop Bus, and its own DIN-8 serial port. Following that came FireWire and the first widespread implementation of USB. USB and FireWire still exist in faster versions that the original incarnations, but now Apple's got Thunderbolt -- yet another fast speed peripheral connection protocol. While eSATA isn't a wide-spread Mac protocol for connectivity, inexpensive cases abound for the connector, which modern Macs without PCI-e slots can't handle. Connectivity specialist Kanex has a solution with the KTU10 Thunderbolt to eSATA and USB 3.0 adapter. Adapters can be problematic, as any computer user knows by now. How well does the small Kanex box suit the bill?

The KTU10 adapter is about the size of a portable computer mouse, and has a four-inch original 10Gbps-capable Thunderbolt cable to connect to a computer. While there are no pass-through Thunderbolt ports, the device provides a single USB 3.0 port, and a single eSATA port. The KTU10 is wrapped in unobtrusive black glossy plastic with no LEDs of any sort. We don't have any problem with the lack of a link light, but this could possibly pose problems for troubleshooting.

Our test platforms were a Mac Mini 2012 i7, a 2012 MacBook Pro with Retina Display, and a 2014 Mac Pro with Thunderbolt 2. All three systems were tested with OS X 10.9.4, with Windows 7 and 8 tested on the MacBook Pro.

We have a wide array of cases and cables to test with, some with intentional flaws to test the durability of the device. Our vanilla tests of the KTU10 worked great on both USB 3.0 and eSATA. USB 3.0 peaked at 4.8Gbps from a SSD in an OWC Aura case. Our eSATA cases, including port multiplying ones, peaked at 3.3Gbps, a bit higher than the 3Gbps Kanex promised with the adapter -- Not SATA-III, but Kanex didn't promise anything faster than 3Gbps over eSATA anyhow. Speed results were identical on all three test platforms. The fittings are precise, the case is well machined and fits well. The case doesn't get so much as warm, even with extended transfers.

We have a problematic USB 3.0 cable that we use for testing. The cable is from an early run of USB 3.0 cables, that implemented ferrite beads for interference control -- we have removed these beads. We can regularly induce a situation with corrupted data transfers using this cable, and with the cable plugged into a port on the computer directly OS X generally identifies the connection problem, and throttles down to USB 2.0 speeds. The adapter seems to prevent this "down-clocking" of the USB connection, and tries to maintain the USB 3.0 speed -- resulting in either a kernel panic or corrupted transfer.

The company specifically states that the adapter doesn't allow booting -- we tested it anyway. Sure enough, the adapter doesn't allow it. No problem, as this was disclosed by the manufacturer, but given some Internet research, this seems to be a sought-after feature, so its worth mentioning.

There are some specific requirements to use the adapter -- OS X users must be on OS X 10.8.4 or greater. Windows 7 and 8 users must install the Kanex driver for the product to be able to utilize port multiplier cases -- cases that show more than one hard drive to the operating system. Hardware RAID eSATA cases, or cases with hardware JBOD arrays aren't subject to the driver installation, as the case is only presenting one logically addressable drive to the computer. Just the same, if you're on Windows, or use Boot Camp to boot into Windows, best to install the driver.

Some early Thunderbolt-equipped Macs don't have USB 3.0 ports, specifically, the 2011 Mac Mini. Not only does the user get a eSATA port, but in conjunction with a USB 3.0 hub, older machines can benefit from the newer protocol, in Kanex's compact package.

There's very little we don't like about the Kanex KTU10 Thunderbolt adapter. The Thunderbolt port is a little short, and dangles off the back of an iMac -- this might lead to strain on the adapter. We've got it connected to an iMac now, so if we see any stress damage in the future we'll update this review accordingly. The adapter uses the ASMedia ASM1042 USB and ASM1061 SATA bridge board chipsets -- we'd like something a little more "burly" for lack of a better term, but they do get the job done.

Users could complain about the lack of pass-through Thunderbolt ports, but the Intel Port Ridge chipset keeps the price down, and doesn't allow for a pass-through port. We're not super-fond of the shiny black plastic, but that's not really a detriment to the product and is only cosmetic. During the course of researching the product, we found some adopters having problems with the adapter just not working right, or at all. We spoke with Kanex support about some of these problems, and they suggested a PMU reset for people exhibiting problems with connectivity. We used the KTU10 with the three different test computers, schlepped it around to various test sites, and still had no problems with durability or connection stability.

The Kanex KTU10 Thunderbolt adapter won Best of Show at the 2014 MacWorld Expo. We understand why. For a low price, the product does exactly what it says it will, and in some cases, over delivers. The eSATA protocol isn't widespread for OS X users, but it is relatively speedy, and inexpensive. Kanex's KTU10 opens up a wide array of enclosures for Mac users, that they may not have had access to otherwise, for one of the lowest prices of entry we've ever seen for a Thunderbolt peripheral. That said, we are disturbed by reports on the Internet of durability issues, and we will keep an eye on this going forward -- if it maintains itself well, we're going to bump it up to 4.5 out of 5 stars. If it falls apart (and we're not seeing any signs of that), that's another matter.