SSL 2
Two channels of console-grade capture in a box that weighs less than a paperback.
Overview
The SSL 2 is a two-channel USB audio interface. Pick one up and the weight is the first thing you notice: 880 grams, in a chassis 234mm wide by 157mm deep by 70mm tall including the knob heights. It's a desktop box, not a rack piece, and it's meant to sit within arm's reach rather than behind a patchbay.
The rear panel carries the connectivity. Analogue inputs 1 and 2 are XLR combo connectors for microphone, line, or instrument sources. Gain control, source switching, phantom power, and the Legacy 4K analogue enhancement are all handled from the front panel, not the back. Analogue outputs are on 1/4-inch TRS jacks, and the stereo headphone output has its own 1/4-inch TRS jack. Monitor output level and the monitor mix - both the USB blend and the stereo input - live on the front panel, as does headphone level. A single USB 2.0 Type-C connector handles the computer connection. There's also a Kensington security slot for anyone using the interface in a shared or public space.
The front panel metering tells you how the interface expects to be used. Each channel gets five LEDs: three green, one amber, one red. The manual is explicit about the target. Aim for the third green point, marked -20, and treat occasional excursions to the amber -10 as acceptable. Hitting the top red LED means clipping, and the fix is to lower the gain control or the output from the instrument. Scale markings are in dBFS, so the metering references digital full scale, not an analogue VU convention. There's also a per-channel red LED for the Legacy 4K analogue enhancement, and a single green LED for USB power.
Sample rate support covers 44.1 kHz, 48 kHz, 88.2 kHz, 96 kHz, 176.4 kHz, and 192 kHz. The clock source is internal. The manual notes that 44.1 and 48 kHz remain the common working rates for most production. Stepping up to something like 96 kHz lowers overall system latency, which helps when monitoring guitar amp simulators or virtual instruments through a DAW, at the cost of more hard-drive space per project. Sample rate changes happen in the DAW, not on the interface. Some DAWs allow it mid-session, others require it at session creation.
The latency figures matter most for tracking. Input-to-output through the low-latency monitor mix is under 1ms. Roundtrip latency at 96 kHz measures under 4ms on Windows 10 running Reaper with Safe Mode off, and under 5.2ms on Mac OS running Reaper under the same conditions. For anyone tracking live vocals or guitars against a click, those numbers make monitoring through the box, rather than through the DAW, a workable option.
The preamps are where the SSL 2 makes its case. The microphone inputs carry a gain range of 62 dB, an input impedance of 1.2 kΩ, and an equivalent input noise of -130.5 dBu A-weighted with a 150 Ω termination. Maximum input level is +5.5 dBu. Frequency response is ±0.1 dB, dynamic range is 110.5 dB A-weighted, and THD+N at 1 kHz is below 0.0015% at -8 dBFS and below 0.005% at -1 dBFS. Those are quiet, clean numbers — the kind that let a condenser mic's own self-noise be the limiting factor rather than the preamp.
The line inputs share the same 62 dB gain range and the same 110.5 dB dynamic range, but with a 10 kΩ input impedance and a maximum input level of +24 dBu, which is enough headroom for hot line-level sources. Frequency response tightens to ±0.05 dB, and the THD+N figures match the mic inputs. The instrument inputs also run ±0.05 dB frequency response and 110.5 dB dynamic range, with a 1 MΩ input impedance and a maximum input level of +15 dBu. The high impedance is what guitars and basses need. The manual explains that engaging the HI-Z switch alongside the LINE switch changes the input stage impedance specifically to retain high-frequency detail from these sources. HI-Z does nothing on its own; it only functions when LINE is engaged.
The monitor outputs are balanced, with a 112 dB A-weighted dynamic range, ±0.05 dB frequency response, THD+N below 0.0012% at -8 dBFS and below 0.002% at -1 dBFS, a maximum output level of +12.5 dBu, and a 1 Ω output impedance. The headphone output runs 111 dB dynamic range, ±0.05 dB frequency response, THD+N below 0.0015% at -8 dBFS and below 0.0020% at -1 dBFS, a maximum output level of +10 dBu, and a 10 Ω output impedance.
The switching logic is simple once you see it. For a dynamic microphone, none of the top three switches - +48V, LINE, HI-Z - should be engaged. Plug into input 1 or 2 via XLR, raise gain until you're consistently getting three green LEDs, and optionally press the Legacy 4K switch to add analogue character. For a condenser microphone, engage +48V and leave LINE and HI-Z unpressed. Expect the top red LEDs to blink while phantom power is applied, with audio muted for a few seconds. For a guitar or bass, +48V stays off and both LINE and HI-Z go down, then you set levels the same way.
The default test configuration for all quoted audio performance figures is 48 kHz sample rate and 20 Hz to 20 kHz bandwidth, with a measurement device output impedance of 40 Ω (20 Ω unbalanced) and input impedance of 200 kΩ (100 kΩ unbalanced). All figures carry a tolerance of ±0.5 dB or 5% unless otherwise stated. That's the fine print, and it means the numbers above are measured values under a stated, repeatable condition, not marketing peaks.
The available period documentation on this interface is thin. A search of the magazine corpus turns up only adjacent studio-listing material from Mix-Magazine (1997, p.82) and Mix-Magazine (1998, p.67) - studio directory entries, not reviews or measurements of this interface. No contemporary review with independent bench testing appears in the available chunks, so the performance figures here come from the manufacturer's own manual, not third-party verification. Treat them as manufacturer claims, well-specified but not independently corroborated in the sources available to this archive.
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