SSL Alpha 8

SSL have chosen not to build mic preamps into their new Alpha 8 ADAT expander — but they have included a whole heap of other features.

Over the last few years, Solid State Logic’s product designers have displayed two admirable features: a focus on innovation, and joined‑up thinking. Recent products of theirs have stood out from the crowd, whilst at the same time fitting neatly into a wider ecosystem. The latter attribute is especially apparent with their UF and UC controllers, and the SSL 360 Plug‑in Mixer, but it extends right across their product range, and SSL’s 12 and 18 audio interfaces are no exception. They also have expansion potential, courtesy of their ADAT Lightpipe ports — and now there’s a partner product tailored to exploit this.

The 1U rackmounting Alpha 8 is primarily conceived as an ADAT expander and, as such, can work with any ADAT‑equipped audio interface, not just the 12 or 18. But, unusually, it also has a USB‑C socket of its own, meaning that it can also be used as an interface in its own right. And, in keeping with SSL’s focus on innovation, it departs from convention in many other ways too.

In the current market, for example, it stands out by virtue of the fact that it doesn’t have any mic preamps. Back when everyone was still working with analogue mixers, this was the norm for ADAT expanders (remember the Fostex VC‑8?), but it’s more usual today for them to be, in effect, eight‑channel preamps. Examples include the Focusrite Clarett+ OctoPre, Audient ASP880 and EVO SP8, Behringer ADA8200, RME Octamic II and so on.

Further differentiating the Alpha 8 from more typical devices is the provision of a headphone output, a dedicated coaxial digital input and output, and the ability to switch its second pair of Toslink connectors to S/PDIF. There’s word clock out as well as in. The analogue I/O is DC‑coupled, meaning that it can be used to transmit and receive control voltage signals as well as audio signals. And, to top it off, there’s an unusual degree of flexibility about how all this I/O and routing can be configured.

If you need more I/O, but don’t need or want it to have built‑in preamps, the Alpha 8 represents a compelling combination of audio quality, versatility and value for money.

Expansive Visions

In terms of industrial design, the Alpha 8 is very much of a piece with the 18 and other recent SSL hardware, meaning that its construction is beyond reproach. It’s finished in a smart workmanlike grey, and can accept mains power directly on an IEC socket. This is joined on the rear panel by the two pairs of optical connectors, the coaxial S/PDIF and BNC word clock terminals, and the aforementioned USB port, plus two sets of eight balanced jack sockets. These provide eight balanced inputs and the same number of outputs, and when the Alpha 8 is employed as an audio interface, are useable in tandem with the digital I/O to provide up to 18 ins and outs at base sample rates. When it’s used as an expander, of course, the analogue ins normally feed the digital outs, and vice versa, though as we shall see, there is some flexibility here.

The only socket on the front panel is the headphone amp. This is of the same design as that used in the 12 and 18, meaning that it offers three different gain ranges to suit whatever type of headphones you have available. In some circumstances, it could be pressed into service to provide an additional foldback source for a performer, but its primary role is diagnostic, allowing you to ‘sniff’ the signal at any of the Alpha 8’s inputs or outputs.

The rest of the front panel is given over to an unusually comprehensive selection of buttons, through which much of the Alpha 8’s versatility is unlocked. Buttons labelled 1‑8 allow you to select one or more channels from whichever ‘bank’ of I/O is chosen using the Ana, Dig, In and Out buttons. So if, for example, you wanted to select analogue outputs 1 and 2, you’d select Ana and Out, hold down 1 and then select 2 as well. Selecting I/O in this way has two main purposes. First, it determines what is heard at the headphone port, and second, it allows you to change the alignment level of the analogue paths. For the latter purpose, you can select any combination of the eight channels within the Ana In or Ana Out bank, while the headphone output picks up only the first selected channel or odd/even pair. Thus if you had Ana In 3, 4, 7 and 8 selected, you could adjust the sensitivity of all four of these analogue inputs at once, but the headphone output will present the signal coming in at 3+4 and ignore the other pair.

Lining Up

Four separate alignment levels are available for the analogue inputs and outputs, and are cycled using the Level button to the right of the meter section. The options are +9, +18, +20 and +24 dBu. The ability to adjust the alignment in this way might sound like a minor technical detail, but I can’t stress enough how valuable it is in practice. Not only does it allow you to calibrate the entire unit to whatever standard is applicable for your particular region, but it makes it trivially easy to realign individual inputs and outputs to accommodate obscure, vintage or semi‑pro gear that doesn’t adhere to any recognisable standard. You need never again be in that position where your drum machine barely tickles the meters, or where you can’t drive an outboard compressor hard enough to do any actual compression.

And if that sounds like a feature you’d expect to be universal on products of this type, a quick glance at the specs of other ‘line level’ ADAT expanders will make clear that it very much isn’t. Arturia’s Audiofuse X8 In and Out offer a default alignment of +24dBu, which can optionally be ‘padded’ down to +12dBu on the input side, while Ferrofish’s Pulse8 AE has a fixed +20dBu aligment, and that of Black Lion’s Revolution EXP is set at +16dBu. You would have to move significantly upmarket, to something like RME’s M‑1620 Pro, in order to gain similar per‑channel alignment options.

The Level button is part of a group that also includes dedicated buttons for cycling through clock source and, when the Alpha 8 is not externally clocked, sample rate, plus a cogwheel Settings button. This is used to access some of the Alpha 8’s global configuration options. For example, the primary role of the second pair of optical ports is to support S/MUX operation at high sample rates, but if you don’t need them for ADAT Lightpipe, they can be repurposed to carry a stereo S/PDIF signal. And if you want to use the Alpha 8 as an audio interface in its own right, you’ll want to delve into these Settings options to tell it to map the physical I/O onto the USB input and playback channels. The only thing obviously missing from the routing options is the ability to have the analogue outputs mirror the analogue inputs, which might conceivably be useful under some circumstances.

Off The Buses

The Alpha 8’s ability to act as an audio interface opens up some interesting possibilities. If you’re working with an external mixer, line‑level I/O may be all you need, and of course its digital I/O could then be used for further expansion. Within a Mac‑based system, SSL also envision it being used as part of a Core Audio aggregate device, alongside an 18 or other audio interface. There’s no reason why this shouldn’t work, although you wouldn’t be able to include any of the Alpha 8’s inputs in a low‑latency monitoring scenario.

The Alpha 8’s USB‑C port allows it to act as an audio interface.

What did slightly surprise me, given SSL’s laudable emphasis on interconnectedness, is that the Alpha 8 is not integrated into the SSL 360 ecosystem. When used as an expander alongside a 12 or 18, the additional ADAT channels show up as you’d expect, but if you connect the Alpha 8 directly over USB instead, 360 simply reports ‘no device’. I’m not sure if it would be technically feasible to aggregate multiple USB interfaces within 360 rather than Audio MIDI Setup, and in any case the Alpha 8 does not have an internal mixer that could be controlled from SSL 360. However, I would perhaps have expected SSL to have implemented some way of configuring the Alpha 8 from an attached computer. As it doesn’t have a screen or even a numeric display, visual feedback when choosing settings from the front panel is communicated through the meter LEDs, in a rather limited and cryptic fashion. A software configuration utility would make it much clearer and simpler, and I hope SSL will add something like this to 360 at some point.

The ability to adjust the alignment might sound like a minor technical detail, but I can’t stress enough how valuable it is in practice.

In practice, though, the reason these global configurations are buried in a Settings menu is that you won’t need to change them very often. For nearly all users, I imagine, the default routing will be the most useful; and many rival products don’t even offer similar configuration options, let alone a way to adjust them from an attached computer.

For nearly everyone, then, the Alpha 8 will be a ‘plug and play’ device. And even if you ignore its additional possibilities, it has several advantages over the competition. Perhaps the biggest of these, to me, is the per‑channel variable alignment. Many other ADAT expanders in this price bracket can’t accommodate +24dBu at all, and none offer the same flexibility to choose other alignments. The onboard headphone amp is also a masterstroke on SSL’s part, making troubleshooting so much simpler. And the Alpha 8 tops the class when it comes to audio specifications, with a dynamic range of 120dB on the inputs and 123dB on the outputs.

Amongst directly comparable products, only the Arturia X8 In and X8 Out come close in terms of audio specs. These also have the advantage that you can add inputs and outputs separately, so you’re not paying for I/O you don’t want; on the down side, metering is almost non‑existent, they have word clock in but not out, and each of them requires its own external wall‑wart PSU. If you widen the comparison to include mic‑level ADAT expanders, which can of course accommodate line‑level signals as well as mics, then something like the Focusrite Clarett+ OctoPre offers broadly similar audio performance, but it’s limited to +18dBu on the output side. And none of the other expanders I know of has the Alpha 8’s USB connectivity or headphone output. If you need more I/O, but don’t need or want it to have built‑in preamps, the Alpha 8 represents a compelling combination of audio quality, versatility and value for money.