27 May 2024

Road Test: Solid State Logic Pure Drive Octo

by Andy Stewart

When it comes to high-end analogue preamps, SSL has, in recent decades at least, designed some of the world’s best. Famous already for its SuperAnalogue, low-distortion preamps, SSL is now keen to add the words ‘harmonic distortion’ to company’s list of associated terms. But is the Pure Drive Octo just a preamp, or is there more to it?

For decades now, Solid State Logic (SSL) has sat comfortably at the exotic end of the pro audio spectrum; its large-format consoles arguably the most iconic of any professional analogue board in history. More songs have been mixed on an SSL in the last 50 years than any other, and still the most clichéd image of a person depicted ‘in the studio’ typically shows someone sitting at an SSL console.

Many of the best studios on earth still have an SSL dominating their main control room, although these days no-one feels compelled to own one. Neve, API, Focusrite and several other brands also provided epic doses of high-end esoterica and gravitas back in the day; indeed, some still do. And of course, plenty of studios abandoned large-format consoles altogether years ago.


But realising the lingering desire of many to own their ‘dream SSL’ one day, a few years ago, SSL released its ‘Origin’ console, to satisfy the sustained global demand for large-format analogue consoles, and to provide a new option for people who were otherwise being forced to play Russian roulette in the second-hand market. The preamp in the Origin console features SSL’s new ‘Pure Drive’ preamp; a blending of the company’s pristine SuperAnalogue design concept of some years ago now with a controllable dose of harmonic distortion, to create a more versatile and even more reliable next-generation SSL preamp.

This next-gen circuitry has now been transported across into two new products: the SSL Pure Drive Octo and Quad preamps – 19-inch rack-mounted versions of the SuperAnalogue Pure Drive microphone preamp, with several impressive additional features added to the equation.

The preamps themselves are everything we’ve come to expect from SSL: they’re beautifully made, ergonomic, gloriously tactile, deceptively versatile and amazing sounding. Unsurprisingly, the Octo Pre has the eight preamps – hence the name – featuring all the usual control suspects, but it’s how these are deployed that really sets the Octo apart.


Indeed, the SSL Pure Drive Octo preamp, which I’ve been testing for a couple of months now, offers so many features beyond providing a simple mic/line amplifier that the word ‘Preamp’ in the product name arguably sells this unit well short.

Fundamental stepped gain is provided in smooth and understated 6dB increments out to +65dB, while a secondary trim control knob per channel provides a finer 1dB gain resolution (+/–15dB). Phantom power is tastefully deployed (per channel) by simply pressing and holding individual preamp gain pots, meanwhile a polarity inverter is similarly engaged by clicking (but not holding) the gain pot.

A fixed 75Hz high-pass filter is also accessed in this manner, this time via the trim pot, while pressing and holding said pot toggles individual channels between mic and line.

The status of each of these control options is clearly expressed via bright green LEDs in classic SSL style. Particularly in dim studio light and with many of these features engaged, the Pure Drive Octo preamp lights up the room like a Christmas tree.

But the feature list doesn’t end there… not by a long shot.

Below each channel’s dual control knobs are a couple of soft switches that access even more sonic options and functionality. The left of these individual pairs of switches, labelled ‘Z’, offers four different impedance options for microphone matching and tonal colour shaping. Conveniently, the different ohms ratings are themselves LED-backlit and colour-coded, a legend for which is printed on the front of the unit – luminous Green: 12kΩ, Amber: 600Ω, Red: 400Ω, and ‘Off’ (no light): 1.2kΩ.

Staying with this left control soft-switch for a moment, here we can also access an insert point per channel that’s physically available on the back of the unit via D-sub connectors. To access this function, you must first press and hold the global ‘Insert’ button on the right side of the unit, then switch each individual channel off or on as required. This is a great feature that allows other external gear to be inserted neatly into the preamp, making the Octo behave more like a small console with an internal patchbay.

Moving next door to the right soft-switch, here we can access arguably the unit’s most noteworthy feature – Drive. There are three different types of harmonic distortion characteristics in the preamp stage of the Pure Drive Octo that SSL defines as: ‘Clean’, ‘Classic Drive’ and ‘Asymmetric Drive’. ‘Clean’ – somewhat predictably – offers an impressively low-distortion SuperAnalogue preamp stage that sounds clear, detailed, and (some might say) colourless. To my ear this preamp option sounds superb on just about everything, vocals in particular, although in an age where preamp popularity contests mostly revolve around distortion and limiting characteristics, SSL’s super clean option no doubt gets criticised already for lacking ‘character’. But that’s precisely not what these acclaimed preamps are about to begin with. They unapologetically offer a super-clean window into any source, like a microscope or a new car windscreen. There is no colouration here, no smudges on the glass…

But if it’s colour you want, you can easily switch the Octo to ‘Classic Drive’, which immediately provides your signal path with predominantly odd harmonics that tend to drive any input signal into euphonic distortion, depending on the gain settings. This option sounds great on most recordings that require a bit of roughing up on the way into your DAW: drums, guitars, basses, frankly anything that needs to be pushed, particularly when you make the most of the Octo’s two-knob architecture that allows you to first add ‘too much’ gain, then trim it back so that it’s not clipping the output or pushing other links in the audio chain into further distortion.

But if that’s not enough, the unit also has a third, ‘Asymmetric Drive’ mode which adds predominantly even-order harmonics, which makes the input signal notably darker, thicker and more compressed sounding. This is probably the most ‘old-school’ sounding of the three preamp modes.

But Wait, There’s More

All these features of Drive, gain and trim, combined with the various impedance options make the eight preamp channels of this SSL unit incredibly versatile and fun to play with… and there are also (before I forget) four unbalanced Hi-Z DI inputs with auto input detection on the left side of the front-panel and eight PPM meters on the right. There’s also a soft on/off switch top right (and a hard on/off on the back panel). But we’re not done with this unit’s ‘preamp’ facilities yet…

There are two more switches on the right side of the unit, directly below the global insert switch – Rate/A/D and Clock – that reveal other obvious tricks this unit has up its sleeve (although the back panel tells the real story here).

The Octo features an integrated USB soundcard providing eight channels of audio into your DAW at up to 32-bit/192kHz. There are four AES/EBU output pairs, and ADAT out, offering eight channels at 24-bit/48kHz, or up to four channels at 24-bit/192kHz via SMUX. The AES and ADAT outputs can even be individually repurposed to be fed from the onboard USB soundcard as outputs from your DAW. There’s also word clock in and out, eight rear-mounted combo XLR inputs, and three sets of D-sub connectors for line-level inputs, insert sends and returns.

The SSL Pure Drive Octo is a classy unit overall. It is modern, feature packed, simply laid out and great sounding. It is beautifully constructed, well vented, and from what I can surmise, fan-less, which means it is quiet but also tends to get relatively warm. The digital conversion and interconnectivity are great additional features that take the unit well outside the scope of a ‘simple external preamp’. The unit is not cheap by any means (what SSL product is?) but the quality is plain here for all to see, making this unit a worthy addition to any studio.

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