The company did not start as a hardware maker. Its route into pedals and modelers runs through software, and its founder still runs it today123.
The story: from plugin studio to hardware
Neural DSP was initially known as a plugin studio, developing software tools for guitarists and bassists. Doug Castro, the company's founder and CEO, described that origin himself1:
"initially, we were known as a plugin studio, developing great software tools that make world-class tones accessible to guitarists and bassists"
The move into hardware brought manufacturing with it. The company, initially known as a plugin studio developing software tools for guitarists and bassists, made what its founder called "the hard decision to move that entire operation to Finland"1. Today Neural DSP runs its own production in Finland and provides cloud services as part of the Cortex ecosystem, with a team of more than 100 people1.
Beyond the hardware itself, the company's work now spans several areas:
- Software tools for guitarists and bassists, where it began1
- Hardware production in Finland, including the Quad Cortex1
- Cloud services, which Castro called "an integral part of the Cortex ecosystem"1
Together, Castro said, these made Neural DSP what he described as a fully-fledged production company1.
Known for the Quad Cortex and the Cortex range
The company's flagship is the Quad Cortex, which Neural DSP set out to build as what it called "the most powerful floor modeler on the planet"5. Around it sits a range of smaller units:
| Product | What it is | How it differs |
|---|---|---|
| Quad Cortex | Floor modeler with two expression pedal inputs6 | The full-size flagship |
| Nano Cortex | Smaller form factor alternative7 | For fly dates or a secondary pedalboard; has a capture footswitch and boost switch7 |
| Quad Cortex mini | Amp and effects processor scaled to pedalboard size8 | One expression pedal output; a second requires MIDI8 |
On the Vertex Effects podcast, Mason Marangella described the Quad Cortex as "the big brother to the Nano Cortex," positioning the smaller unit for players who "need a smaller form factor, something again, that's going to help your fly dates or it's going to help your secondary" pedalboard7.
Guitar.com's Josh Gardner reviewed the Quad Cortex mini in February 2026, noting that it scales Neural DSP's "hugely popular amp and effects processor" down to pedalboard-friendly levels, and that it is "also very nice to be able to try out a bunch of captured dirt pedals in the chain, too"8. On the mini's reduced I/O, he wrote: "these feel like the sort of niche-use luxuries that I'd be happy to sacrifice to get a Quad that fits on my Pedaltrain"8.
The Quad Cortex mini's smaller chassis costs it some connections: it has one expression pedal output instead of the Quad Cortex's two inputs, and running a second expression pedal requires a connection over MIDI68.
Doug Castro, founder and CEO
Doug Castro is the founder and CEO of Neural DSP4. He is the voice behind the company's development updates, where he has explained both the plugin-studio origins and the Finland manufacturing move1. Guitar.com noted that it had been less than five years since the site's world-exclusive review of the original Quad Cortex, a span that covers the company's whole hardware history under Castro's leadership8.
Expression pedals and control
The Quad Cortex features two expression pedal inputs6. According to Neural DSP, expression pedals "can be assigned to almost any parameter within the available virtual devices, and can even control multiple parameters at the same time"6. Over MIDI, expression pedal 1 responds to CC# 1 and expression pedal 2 to CC# 2, both with values 0 to 1279.
| Control path | What it does |
|---|---|
| Expression pedal input 1 | Assignable to almost any parameter; responds to MIDI CC# 1, values 0 to 12769 |
| Expression pedal input 2 | Assignable to almost any parameter; responds to MIDI CC# 2, values 0 to 12769 |
| One pedal, multiple parameters | A single expression pedal can control several parameters at once6 |
Jim Dunlop makes an expression pedal line, the XP series, designed to take control of Neural DSP's Quad Cortex modelers, matched to the devices10. The Quad Cortex also integrates with amp switching: KHE Audio Electronics documents using the QC's pedals (boost, overdrive, gate and such) in front of amps, like normal pedals, in a four-cable-method setup with its amp switcher11.
The range (3)
| Type | Pedals |
|---|---|
| Multi-effects | Neural DSP Nano Cortex, Neural DSP Quad Cortex, Neural DSP Quad Cortex mini |
News
Questions
Who founded Neural DSP?
Doug Castro is the founder and CEO of Neural DSP. He led the company from its beginnings as a plugin studio making software tools for guitarists and bassists, and later made the decision to move the company's hardware manufacturing operation to Finland, where the Quad Cortex is built.
Where is the Quad Cortex made?
The Quad Cortex is made in Finland. Doug Castro moved the company's entire production operation there in 2022, after silicon shortages and logistics bottlenecks made the previous arrangement unworkable. The Finland facility was running almost at capacity by mid-2022, with production of thousands of units per month expected during the fall.
How many expression pedals can the Quad Cortex use?
The Quad Cortex has two expression pedal inputs. Expression pedals can be assigned to almost any parameter within the available virtual devices, and a single pedal can even control multiple parameters at the same time. Over MIDI, expression pedals 1 and 2 respond to CC# 1 and CC# 2 respectively, with values 0 to 127.
What is the difference between the Quad Cortex and the Nano Cortex?
The Nano Cortex is a smaller form factor alternative to the Quad Cortex, which Vertex Effects' Mason Marangella described as its big brother. It suits fly dates or a secondary pedalboard where the full-size unit is too much. It carries a capture footswitch and a boost switch rather than the Quad Cortex's larger control set.
Does the Quad Cortex mini have an expression input?
The Quad Cortex mini has one expression pedal output, and running a second expression pedal requires a connection over MIDI. Guitar.com's reviewer called this and the mini's other I/O reductions niche-use luxuries he would happily sacrifice to get a Quad Cortex that fits on a compact pedalboard.
Sources (11)
- Quad Cortex Development Update #25, Neural DSP, 2022-06-28
- Neural DSP Nano Cortex, Sound On Sound
- NAMM 2020 VIDEO: Neural DSP's AI-powered floor modeller is 'Vulgar Display of Power' | MusicRadar, MusicRadar, 2020-01-18
- Quad Cortex Pre-Order Shipping Schedule, Neural DSP, 2021-02-08
- Cloud backups!, Neural DSP, 2020-09-25
- Quad Cortex Expression Pedal Compatibility, Neural DSP, 2021-02-02
- This Pedal Just Changed the Amp Modeling Game, vertexeffects.com, 2024-10-03
- Neural DSP Quad Cortex Mini review: too good to be true?, Guitar.com, 2026-02-20
- Voes | MIDI-CC, Voes, 2024
- DUNLOP XP SERIES EXPRESSION PEDAL FOR NEURAL DSP QUAD CORTEX, Jim Dunlop (jimdunlop.com)
- KHE + Neural Quad Cortex 4CM, KHE Audio Electronics