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Black Lion Audio Revolution 2x2

USB Audio Interface By Sam Inglis
Published April 2021

Black Lion Audio Revolution 2x2

With their debut audio interface, Black Lion Audio say they’re putting quality first.

Black Lion Audio have built up a loyal following for their audio interface ‘mods’. You send them your interface, and they’ll perform open heart surgery, upgrading various components that can have an influence on the sound quality. Typically, this involves replacing op‑amps, modifying the filtering on power rails, and introducing their own decoupling circuitry around A‑D and D‑A converter chips. Depending on the product, it can also mean replacing the system clock and substituting components such as capacitors with premium alternatives.

In recent years, the company have also introduced a number of their own products, including mic preamps, compressors, power conditioners and word clocks. Until now, however, it’s not been possible to buy an ‘off the shelf’ audio interface that incorporates all of Black Lion’s modifications as standard.

Vive La Revolution

The Revolution 2x2 is a bus‑powered USB audio interface that occupies a 1U, half‑rack shell. Its feature set is familiar from many other such interfaces. Two combi sockets can accept either XLR‑M or quarter‑inch jack plugs, and can be individually switched to high‑impedance mode for DI’ing electric guitars. Phantom power is also available for mics, and is switched globally. A single pair of outputs is served up on balanced quarter‑inch jacks, as an S/PDIF digital signal and on a front‑panel headphone socket. A coaxial digital input is also offered as an alternative to the analogue ins.

Direct monitoring of input signals is handled using a simple balance control. With this control fully counter‑clockwise you hear only the input; at the other extreme, you hear only the signal being output by the DAW. For low‑latency monitoring while recording, you’d set it somewhere in the middle to hear a sensible balance of the two, and engage the Mono button if you want to hear the individual sources panned centrally rather than as an L‑R stereo signal. Metering is fairly generous on the output side, courtesy of a pair of eight‑segment LED ladders, but restricted to a single signal present/clip LED for each of the inputs.

The Revolution is a USB 2 device, but has the latest Type C connector on the rear panel, with good‑quality cables supplied to cater for computers with Type C or Type A sockets. Black Lion’s promotional material describes this as a ‘low latency’ connection, but of course latency is mostly dependent on your computer and the drivers. On Mac OS, the Revolution uses Apple’s Core Audio driver for class‑compliant devices and thus offers the same driver performance as most other small USB interfaces. I don’t have a Windows test machine, but Black Lion told me that the Revolution uses a custom Windows ASIO driver commissioned from Thesycon. Like many audio interfaces, the Revolution also ships with a very worthwhile software bundle, in this case comprising PreSonus’s Studio One Artist, iZotope’s Elements Suite, Brainworx’s bx_digital and the Lindell 6X500 plug‑in.

As an exclusively bus‑powered device, the Revolution 2x2’s back panel features just a pair of quarter‑inch audio outputs, coaxial S/PDIF I/O sockets and a USB Type‑C port.As an exclusively bus‑powered device, the Revolution 2x2’s back panel features just a pair of quarter‑inch audio outputs, coaxial S/PDIF I/O sockets and a USB Type‑C port.

Revolution In The Head

First impressions are very positive. In terms of build quality, the Revolution 2x2 is some way ahead of any other comparable interface I’ve seen in the same sort of price bracket. Its metal chassis feels tank‑proof, and it uses premium parts such as Amphenol connectors and good‑quality potentiometers which are beautifully weighted. Internally, it incorporates Black Lion technologies such as ‘Macro MMC’ clocking and ‘PG‑i’ power filtering.

In terms of functionality, though, the Revolution’s feature set pits it against rivals such as SSL’s 2, MOTU’s M2 and Focusrite’s Clarett 2Pre USB, all of which are more affordable and have additional features that are not available on the Revolution. So the case for buying a Revolution 2x2 rests on Black Lion’s claims about its quality. Does it sound good enough to justify the price premium?

In answering this question, it’s important to bear in mind Black Lion Audio’s ethos. The brochure that describes this is overcooked in places (it makes a selling point out of the fact that their “high‑end S/PDIF” has an embedded clock signal) but the core message is consistent. They say their aim was to produce the interface that sounded best to their ears, not the one that performed best on the test bench, and insist that subjective sound quality cannot be reduced to objective measurement. All the significant decisions they made in designing the Revolution 2x2 were therefore decided on the basis of listening rather than numbers. Naturally, they publish specifications, and these are mostly very good, but achieving good specifications was never an end in itself.

Plus Points

The idea that differences can be “instantly apparent to the listener” even though they don’t show up in conventional measurements is one that will divide equipment designers, and it’s not entirely straightforward to test. As luck would have it, I had access to an SSL 2+ audio interface, one of the products that might be considered a rival to the Revolution. However, switching between two audio interfaces is never instant, and it’s not obvious how to connect both to the same playback system without passing through a mixer or other device that could colour the sound.

Eventually, I managed to route both interfaces directly to the same pair of active speakers without putting anything else in the way. Once this arrangement was set up and level‑matched, I found that if I turned my attention to something else, I quickly forgot which interface was active, and simply enjoyed listening to music on either — they both sounded very good. When I did rapid A/B comparisons, though, I sometimes convinced myself I could hear a difference. On some material the Revolution was a hint fuller in the low midrange, and there were occasions when it seemed marginally smoother in the treble. However, such differences as I could perceive were extremely subtle, and I doubt they’d affect any decisions I would make when mixing. To put it in perspective, any difference in what comes out of the line outputs is orders of magnitude less than the difference between two sets of monitor speakers. Having said that, I make no claim to have golden ears, so this is really a test you should try to arrange yourself if you’re interested in the Revolution.

It’s a fact of life that people are recording and mixing music every day in circumstances where mains power is inconvenient or not available, so why not make the best‑sounding bus‑powered device possible?

Differences were, however, much more apparent when I switched to headphones. The Revolution’s headphone amp has a lot more welly than those in the 2+, and sounds very good. I’d go so far as to say that I’ve not heard a better one in any USB bus‑powered interface. However, I’d also point out that that is not a trivial qualification. I can see why Black Lion have chosen to adopt this approach, because it’s the nearest thing we have to a universal interface format, but the limited power available inevitably introduces design compromises. By its nature, a portable USB interface is also likely to be used in circumstances where other factors can affect audio quality. Having a hi‑fi audio interface may be of limited value if you’re working on a tour bus, in a hotel room or in an untreated bedroom studio.

The Audio Went In 2x2

On the input side, Black Lion rightly point out that some conventional preamp specifications, especially Equivalent Input Noise, assume that the preamp is independent of the A‑D converter, which is rarely true in an audio interface. Their specs thus quote some of these figures in an unconventional format, but they say that EIN would be a very decent ‑127dBu if measured in the normal way. A 55dB gain range is available for microphones, which is broadly comparable to most competing products. Like most interface preamps, these are transformerless and thus offer a clean rather than a characterful sound. However, preamps are also the strong suit of the SSL 2+, which has an extra 7dB gain range available. In a direct comparison, it’s clear that the respective alignment of the A‑D converters means this comes at the top end of the scale, making it slightly easier to work with quiet sources such as spoken word on the SSL.

As I’ve already suggested, anyone creating an ‘audiophile’ bus‑powered USB interface is working within self‑imposed limitations. No such device will deliver the full +20 or +24 dBu output level that’s expected by most professional studio equipment, for example — but then, in practice, how often is something like the Revolution 2x2 ever going to be used within that sort of environment? It’s a fact of life that people are recording and mixing music every day in circumstances where mains power is inconvenient or not available, so why not make the best‑sounding bus‑powered device possible? That’s what Black Lion have set out to do with the Revolution 2x2, and they’ve done a great job.


  • Extremely well built.
  • Very good subjective sound quality.
  • Easy to use.


  • Not everyone will feel that the difference in sound quality justifies the additional cost compared to rival products.


Black Lion Audio have put a lot of thought into creating the best‑sounding portable, bus‑powered interface they possibly can.

Published April 2021