Plenty of people still own PCIe audio interfaces, but in the past, these have been limited to use with larger tower computers with PCIe slots. Many now record on laptops or other smaller portable computers that are physically unable to accommodate PCIe cards, but still desire the speed and reliability of these PCIe-based systems. OWC (along with other companies such as Sonnet) have offered up solutions such as the Mercury Helios 3S PCIe expansion chassis, allowing users to connect a single PCIe card of their choice to a non-PCIe computer via an ultra-fast (40 GB/sec) Thunderbolt 3 connection.

Upon first inspection, the Helios 3S appears simple, austere, and easy to intuitively disassemble. The rear panel has two Thunderbolt 3 ports, including one 85 watt connector for notebook charging during operation. An additional DisplayPort 1.4 (up to an 8k) and locking 12V power supply connector are also on the rear. I wanted to use a Focusrite RedNet Dante PCIeR card as an audio interface with my Mac mini, so the Helios 3S seemed to be a good option for my needs. Installing the card in the chassis took about a minute, and after that, it was pretty much “plug and play.” The Helios 3S chassis requires no drivers or set up, and my Mac mini immediately recognized the Dante PCIe interface. The Helios 3S is lightning fast and stable with my Focusrite Dante card. I’m getting a roundtrip latency of 1.6 ms at 96 kHz (64 ms buffer in Pro Tools) with the card in the Helios 3S chassis to and from my iZ RADAR Converters [see review this issue]. This kind of speed is very impressive for a native system. In the month since I have been using it, the Helios 3S has been rock solid without a single problem. The unit does have a small fan, but it is virtually silent and unlikely to be a problem even in a quiet listening environment. The 12V power supply is external and somewhat large but in no way problematic. Overall, the OWC Mercury Helios 3S is an excellent, affordable option for those interested in using a PCIe card solution with a Thunderbolt-equipped computer. Set up is straightforward, and it performs extremely well for pro audio applications.

Tape Op is a bi-monthly magazine devoted to the art of record making.

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