I made the switch to amp modelling years ago. For such a long time, I had been an avid user of physical amp modellers. A few years ago, software amp modelling also started to catch up.

It's a head trip to think that there are up and coming guitarists out there who have probably never owned a physical amplifier and been purely modelling—never knowing the pain of connecting your pedals, identifying a bad cable in your signal chain and working out how to not only power everything but neatly run the cables.

When the Neural DSP Quad Cortex was announced, my curiosity was piqued. Could this little device go toe-to-toe with the big boys in the amp modelling world? Could a Quad Cortex compete against an Axe-FX II or Axe-FX III? How about against a Kemper or Line 6 Helix?

It was this hesitation that made me sit back and not make such an impulsive purchase. That hesitation was a blessing because it allowed me to honestly think about whether or not I needed the Neural DSP Quad Cortex or if I was making an impulse purchase.

Stock levels for the Quad Cortex have been a bit of an issue. But, when a retailer here in Australia started advertising they had a shipment coming in at the end of October 2021, I jumped on it. I reached into the deepest darkest parts of my pockets and found enough to buy one of these beasty units.

As you are probably aware, the Quad Cortex is not cheap. It's in short supply too, so used prices are sometimes more than RRP for the moment.

Should I buy the Neural DSP Quad Cortex, or wait for a bit?

Should you buy the Quad Cortex? This is probably the question you came here to get an answer to. The answer is; it depends. I recommend that you keep reading to understand the Quad Cortex better, but there are some downsides (easily fixed in future updates) you need to be aware of before making such a large purchase.

One thing you have to realise is you are buying into an early ecosystem. The Quad Cortex is essentially a computer with a powerful specialised chip for audio. It's one of the most powerful modellers around at the moment (I'm sure competitors will catch up).

The amplifier and effects selection pales compared to the Line 6 Helix (or even my old HD500x), Kemper or Axe-Fx III. The initial experience is a little thin, but given this thing only started shipping in March 2021 and the pandemic supply chain issues have made electronic component availability and shipping difficult, it's early days.

There seem to be more people joining the app each day, and thanks to its custom capture feature, captures are being regularly pushed to the cloud you can access, which effectively give you new amps and effects as you can capture both. The capture feature is the flagship feature of this thing, and we will get into that later on.

The Line 6 Helix is going on seven years now, and despite its age, it's still a solid modeller being updated and improved. There will undoubtedly be a Helix 2 coming soon, most likely going toe to toe with Neural DSP.

If amp modellers were judged solely on amps and fx selection, the Quad Cortex right now would not win. The strength of the Cortex is the quality of the sound and the ability to capture amplifiers, pedals and even VST plugins.

Build Quality

The Quad Cortex build is impressive. A complete metal chassis, a seven-inch colour touchscreen, switches that are both rotary and stomp. A 2GHz SHARC+ processor lives inside, giving you the ability to create sounds so wild and crazy, you'll never experience a DSP limit ever again (something that happened to me a lot with the POD).

Those foot stomp rotary switches are a gamechanger, in my opinion. I have no idea why no other device has thought of doing this, but it does make the QC feel like more of a hardware product than a software one.

Time will tell if the rotary stomp switches hold up in the long-term, but they did allegedly test these with some robot that just hit them repeatedly until they broke, and they last for weeks (allegedly).

What will pleasantly surprise you when you first get your hands on the QC is how small and light it is. Looks can be deceiving, it might be small, but it's mighty. You could throw this thing down a flight of stairs, and it might get some scratches and dings, but I doubt it would break (I don't want to find out).

Could you tour with the Quad Cortex? Absolutely. Mike Stringer from Spiritbox has switched over to using the QC on tour, and this guy is known for previously using Axe-FX and Kemper.

It's pretty impressive that they've managed to make a device suited for the home studio but also rugged enough to tour with it. Usually, tour proof equipment isn't known for being the prettiest. I recommend buying the carry case for the Quad Cortex (sold separately), which will protect your QC if you're travelling with it.

The touch screen is one of the most impressive things about the Quad Cortex. It's highly responsive, similar in response to a phone or tablet display. I was sceptical, but it's remarkable how quickly you get used to the touchscreen and rely on it. You soon forget you can't create presets outside of the device yet.

Sound Quality

Before the Quad Cortex became a reality, Neural DSP was already well-known for its fantastic VST plugins. The Archetype plugins are some of the most realistic and impressive modeller VST plugins around. I've been a massive fan of the Nolly plugin since it was released and then the Gojira one too.

I was pleasantly surprised how good the Quad Cortex sounded out of the box. I mean, I turned it on and started going through the stock presets, and I was blown away by how good they sounded for stock presets. My point of reference for out of the box sound was the Archetype plugins.

And then, I created my own preset. I created a preset to replicate the bluesy overdriven sound of some of Thrice's earlier work (particularly the Beggars album). It was pretty easy to create a preset that combined two amps with some pedals.

I am not an expert at creating patches yet, but Neural DSP has managed to get some of their artist ambassadors to create some captures and presets available on the cloud. The Rabea presets are incredible if you want some more rock-oriented sounds.

If you are looking for some metal rhythm and lead presets, Baris Benice has you covered with a selection of some punchy and unique metal presets.

Someone who is using the Quad Cortex to full effect is Mike Stringer from the band Spiritbox. He has switched over to the Quad Cortex for his live setup right now. And even better, he has presets and captures available on his profile. Just search for "mikespiritbox" — Mike uses a capture of an Omega Granophyre, and it's one of my favourite captures/presets around at the moment.

Inputs and outputs

Neural DSP has really thought far ahead with the sheer number of inputs and outputs on offer. Furthermore, the configuration settings allow for all kinds of different combinations. Have outputs on different parts of your signal chain going into different tracks in your editor.

You can seriously control everything. There is even support for 48v phantom power if you wanted to plug in a microphone and power it from the device. You can use the Quad Cortex as a powerful audio interface and modeller. It does everything.

Video

One of my favourite features of the Neural DSP is that you can run multiple instruments into it.

Think of a scenario where you and another guitarist are doing a live show. Instead of lugging amp heads and speaker cabinets, you can both run straight into the Quad Cortex and have different amps/speakers/fx and tweak other facets of your sound individually. Effectively, giving you two amps in one.

If you like to play to your favourite tunes on Spotify or play along with YouTube videos, you can use this as your audio output on your computer. Plug some headphones in and you can play along, with the ability to adjust the volume levels of the mix.

You can even go a step further and become a one-man band, a guitar and a microphone. I wonder if you can run an electronic drum kit into this thing?

User Interface

The user interface of the Quad Cortex takes some heavy inspiration from the Line 6 Helix. As the saying goes, good artists copy, and great artists steal. Line 6 are the Apple of the amp modelling world. They make beautiful devices and have been trendsetters in that regard.

On the screen, colours are vibrant, and fonts are easy to read. Because of the decent screen size, the text is nice and large. In a dark room, the screen pops.

The editing experience is currently done on the device with no PC or Mac editor available (although it is being worked on). As you can see in the following video, it's pretty easy to create presets on the device:

Neural DSP is still expanding the items on selection. By tapping on parts of the UI, you can place blocks that can be amplifiers/cabinets/pedals/noise suppressors and pretty much anything else. The rotary stomp switches allow you to change the settings of your blocks, replicating the feel of traditional dials on an amp or pedal.

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Capturing

The flagship feature of the Quad Cortex that sets it apart from the likes of the Line 6 Helix is the capture feature. You can use this to capture amp heads, combo amplifiers, effects pedals and speaker cabs. The capture process couldn't be more straightforward. The device guides you through the process and shows you what to do.

I don't have much in the way of analog equipment laying around anymore, but I did capture my Positive Grid Spark Amp I had as a test. I was blown away by the accuracy. I couldn't hear any discernable difference. I thought the Quad Cortex capture sounded better to my ears.

I am probably going to start bugging my friends and family to borrow their equipment to capture it. I am even considering renting some equipment from music stores (the kind I could never afford to buy) and then capturing them. I can see this being an addiction.

While this might be mentioned somewhere already, the capturing process can take a while. It's not a two-minute thing. Given what the capture feature is doing, I'm sure you will be happy to wait for the final result.

One thing you can allegedly do with the Quad Cortex is capture VST plugins. I have plans to try and capture some of the Neural DSP Archetype plugins onto the Quad Cortex. I want some of those Tim Henson sounds on my QC.

Final thoughts

I love the Quad Cortex, but there are areas that can and I believe will eventually be improved. The effects selection is a bit dismal at present. I mentioned this earlier, but the Line 6 Helix and even other modellers like the Axe-FX or FM3 have more to choose from.

The Helix has 38 distortion/overdrive pedals, for example, and the Quad Cortex only has a small selection at present. Some more amp and speaker cabinets would be great too (something I know that will happen over time).

Unlike other modelling devices, you also cannot change things like the sag, hum, bias and other more advanced settings that most people probably would never touch. It's worth knowing these are currently not available, but there is no reason why they couldn't be added in future updates.

The boot time for the Quad Cortex is also quite slow. A cold boot seems to take upwards of 40 seconds (it might not be that long, I haven't physically timed it), but it's not quick.

Overall, it's a solid unit right now. To answer the question of whether or not you should buy the Quad Cortex. If you're happy to buy a device that will take another year or two to reach its full potential, buy it.