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Looptrotter Satur-8

Distortion Processor & Summing Mixer
Published January 2013
By Matt Houghton

Looptrotter Satur-8 processor.

Does anyone need eight channels of distortion when summing analogue signals together? Looptrotter might be able to persuade you that the idea's not entirely crazy!

Regular readers may remember just how enamoured I was of Looptrotter's debut product, the Monster, which was (and indeed is) an impressive two-channel FET compressor and tube distortion processor. If you missed that review and would like more background on the company, or more details about that product, check out the review in SOS February 2012 (/sos/feb12/articles/looptrotter-monster.htm).

Looptrotter have applied the same sort of thinking that made the Monster such a rip-roaring triumph to a rather different product, the Satur-8. As with the Monster, this serves dual purposes, but this time there's no dedicated compressor and there are no vacuum tubes either. What it does have in common with the Monster is that it's all about the art of dirtification. To that end, it doubles up as both an eight mono-channel solid-state saturation processor and a stereo analogue summing mixer. On the face of it, then, this sounds like it could be the perfect outboard complement to the modern DAW environment, allowing you to 'warm up' various DAW channels or stem mixes in search of some analogue character, and to sum things in the analogue domain to minimise the number of stages of A-D conversion. Alternatively, perhaps it could be a good partner to a few clean-sounding outboard channels, enabling you to add in the desired amount of attitude.


Each of the Satur-8's channels features both a drive and and an output-level knob, and both feel pleasantly smooth in operation. They take you from pretty much clean to incredibly dirty, with predominantly even-order harmonic distortion. A pair of LEDs indicate when you've reached four (amber) and eight (red) percent THD respectively, but while these are useful broad-brush indicators, the Satur-8 is all about using your ears.

There's plenty of space between the controls, and no annoying play on the pots, and both facts make this processor a joy to use. There's also a distortion on/off toggle switch on each channel, and an LCR toggle, which sends the signal to the left, right or centre of the main mix bus. This is typical of basic summing amps and, as far as I'm concerned, is all you need: if you want to place something anywhere else in the stereo panorama, you just send a stereo signal into two channels and opposition pan them. Obviously, there aren't enough channels here to be able to process and sum every track in your mix. Rather, the idea is to process and sum stems and a few select sources. As well as the basic distortion indicator, there are four-segment LED meters, which you can use to gauge the output level on every channel.

On the right of the front panel you'll find the mix-bus level knob. This is accompanied by two eight-segment LED meters, which enable you judge the master stereo output level. The only other control in view is a chunky metal toggle switch to switch the processor on or off. All the I/O is mounted on the rear panel of this 2U rackmount device, with the eight channel inputs and outputs presented on both balanced XLR and DB25 D-sub connectors — and it's good to have both options available. In addition, there's a pair of balanced XLR outputs for the master mix and a pair of balanced XLR auxiliary inputs, which allow you either to send a main stereo stem to the mix system alongside the signals you're processing with distortion, or — if you really like this sound and have more analogue outputs available in your DAW system — to send another eight channels to a second Satur-8 and route the mix from that to the aux input of the first, giving you 16 channels of glorious dirt in total. It's an expensive but intriguing prospect!

Usefully, there are two pairs of balanced jacks via which you can hook up a master-bus insert chain. Naturally, Looptrotter suggest that this would be a good home for their Monster. That might work for some but, much as I loved the Monster, I'm not convinced that I'd find the appetite for yet more Looptrotter distortion; there's plenty on tap here already. Nonetheless, the ability to insert a decent compressor and/or EQ here is welcome.

Power is supplied via an IEC inlet, which on the review model accepted only 230V AC sources. I assume that a dedicated 110V version will ship in the USA and other territories using that standard. One exterior mystery remains: blanked-out holes suggest that a remote control and further monitor outputs may be added in the future.

Here's a view of what's going on inside the Satur-8. As you can see, the circuit boards are all laid out neatly and there's plenty of space for the heat from the tubes to dissipate.Here's a view of what's going on inside the Satur-8. As you can see, the circuit boards are all laid out neatly and there's plenty of space for the heat from the tubes to dissipate.

When you lift the lid on the box, the circuitry looks surprisingly minimal, with one main processor circuit per channel and another for the master mix circuitry. Each is on its own card and is accompanied by another that hosts the control circuitry and connects to the front-panel controls. There's slightly more going on here than it might at first seem, though, as many of the components are diminutive surface-mount devices (SMDs). There's absolutely nothing wrong with this approach, as long as quality components, within acceptable tolerances, are used — and they are in this case.

Everything, not only the circuit boards, is very neatly laid out, with tidy wiring, and appropriate shielding for the torroidal AC step-down transfomer. The case is rigid, and the controls are nice and firm to the touch, offering pleasing resistance while remaining easy to use.

On Test

There was no manual with the review model, but you don't really need one, as there's so very little that you need to figure out. In fact, thanks to the D-subs, it took me all of two minutes to get the unit plumbed into my DAW and commence with the processing of individual sources — and to achieve results that were in the "jaw-droppingly stunning” ballpark. It took only a jot longer to hook up the mix output to a dedicated stereo recorder and to assess that. So, once your sources are routed to the Satur-8, it's quick and easy to get good, satisfying results.

As you'd anticipate from a saturation processor, the nature of the distortion it creates is very forgiving. Everything feels nicely solid and rounded until you push it that bit too far, and the simplicity of the controls means that if you do that, it's really easy to pull things back to achieve the desired balance of warmth and level across the various sources.

During my 'tests' — which were inevitably more about creative experimentation than anything else — I ran various sources through the Satur-8. Harmonic distortion is such a tricky thing to describe via the written word, so I decided that I'd quickly knock together a basic funk/rock loop of drums, electric bass and electric guitar and see what sort of balance and vibe I could achieve. You can hear the before and after examples on the SOS web site at /sos/jan13/articles/looptrotter-satur8-media.htm. It's always difficult to be definite about these things, as we all have very different tastes, but I certainly felt there was more 'mojo' in the processed signals!

Using a hardware device such as this isn't all about the sound. Having so many channels available with so few easy-to-use controls to juggle makes this a very different tactile experience from deploying a collection of different stereo processors on a bunch of stems, or from using multiple instances of your favourite plug-in. Using the Satur-8 is so reminiscent of using an analogue console, where you have access to common controls for the parameters you need on multiple channels at the same time. That's important, in my view, as when you introduce distortion you affect the perceived loudness of each source, so it inevitably becomes necessary to juggle both the distortion and level controls of the various channels.

Sonically speaking, there's a very definite tube-esque vibe going on here. It's reminiscent of the Monster, although in this case you obviously don't have the same degree of control. There are no wet/dry blend controls, for example, and there's no compressor on hand to sculpt the signal before treating it with distortion — and, as I said earlier, there are no real tubes!

On the rear panel, not only are you greeted with both XLR and D-sub options for the analogue channel I/O, but you have mic outputs and a stereo aux input for cascading multiple units, or sending a clean stereo stem to the mix bus.On the rear panel, not only are you greeted with both XLR and D-sub options for the analogue channel I/O, but you have mic outputs and a stereo aux input for cascading multiple units, or sending a clean stereo stem to the mix bus.Even though this isn't a compressor, it's in the nature of saturation that as you push the input harder, there's some form of dynamics processing going on, and given the output gain/attenuation control, it's perfectly possible to use this device as an analogue limiter in this way — it's just that you have less control over what's happening, and it can't, by any stretch of the imagination, be described as 'clean' or 'transparent'. There's also enough output gain available that you're able to use the drive stage gently while deliberately overloading your A-D converters on the way back to your DAW. The latter trick worked nicely for me on a snare drum, enabling me to add a distorted softness that enhanced the sustain while at the same time achieving an abrupt, cutting attack that made the thing leap out of the mix.

The modular construction suggested to me during tests that versions with fewer channels might be in the offing so, as we were going to press, I wasn't surprised to learn that Looptrotter were launching the two channel Sat2Rate. I suspect that a 500-series module and guitar stomp box would be sensible future additions to the line... but I'm venturing into the realm of conjecture.

Finally, I should make mention of the summing functionality. If the truth be told, I'm not a huge advocate of analogue summing for the sake of it, despite it being very much in vogue. There really is nothing wrong with digital summing these days, assuming you mix well in the first place, and the only differences I can notice in analogue summing are slight imperfections that will be deemed desirable by some people, and undesirable by others — so it's the sort of thing you'll have to assess for yourself! For what it's worth, though, the summing here does the job well enough, and if this sort of thing matters to you, it means your precious audio need only pass through only two, rather than eight channels — or multiples of eight if you're using two or more units — of A-D conversion when capturing the result.


This is a lovely processor that offers a satisfying combination of modern engineering and old-school sound. At this price (£2000 excluding VAT in the UK), it may seem an expensive luxury, but you have to remember that this is eight channels of processing alongside a summing amp: you could easily splurge more money on eight 'boutique' guitar distortion pedals, few, if any, of which would be the equal of this — and you'd still lack the summing. The ability to 'dial in' anything from the subtlest saturation to full-on, fizzing distortion should make this a real hit. I'd quite happily mix an entire track through a couple of these, saving myself a lot of processing decisions along the way. I'd love to hear what this will do in the hands of other people, but I'm already sold on the curiously fuzzy-solid goodness of Looptrotter's Satur-8!  


There are few distortion processors of this quality, and fewer with this many channels and summing. The strongest competition is from Thermionic Culture's Fat Bustard, a tube device which offers more inputs, but there are no channel outputs, only a mix output. The single-channel Fulltone OCD guitar pedal aims to do a similar thing (deliver tube-like distortion without tubes) and does a decent job — but not as good as this.

Published January 2013

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