Eric Johnson Names One Thing Digital Modeling Can’t Do, Says He’s ’Experimenting’ With Neural DSP Quad Cortex

Guitar legend Eric Johnson recently confirmed that he’s now “experimenting” with digital modelers and profilers, particularly Quad Cortex by Neural DSP. Revealing this in the “Dipped in Tone” podcast, Johnson also pointed out that he’s currently working on this but that he’ll most likely never give up on the conventional amps and effects.

Discussing the matter, Johnson said (transcript via Music Radar):

“I think there’s a lot of new gear that sounds great but it’s just a different sound. It doesn’t sound like my mentors and heroes that I grew up on with just that real kind of natural guitar sound. Or what I would consider a natural guitar tone. So I’m pretty much into that and I use a lot of the older stuff.

Eric Johnson - Manhattan (Live In Concert)

“I do experiment with new stuff every now and then… It’s really how it tracks when you play, when you lean into it and really push the envelope of what you’re playing. How’s the envelope expanding and contracting with the dampening of the amp? How is it following suit with your picking technique?

“And a lot of stuff, it doesn’t follow your picking technique… you can feel it kind of fighting you. And to me, that’s not as inspiring of a thing. So I look for something that follows the picking technique as much as possible.” 

And while discussing the matter, Johnson confirmed his involvement with Neural DSP by using the company’s Quad Cortex and tweaking the sounds to his liking:

“I’m experimenting with the Neural DSP [Quad Cortex] right now and we’re capturing sounds and I’m gonna keep capturing sounds on it. The company has been gracious to allow me to work with a unit.”

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Eric, who’s well-known for being one of the most meticulous guys about his gear, says that he feels like the technology has gotten much better over the years, making him feel “encouraged.” He offered:

“I’m kind of encouraged. I think that concept gets better all the time. I don’t know if it’ll ever completely replace the [original] stuff but I’ve been working with Neural. We’ve done a few captures so far and I could almost use that – it’s pretty close. I’m going to continue working with it and see what I can do with it.”

On the other hand, Johnson also points out one particular issue that he has with these types of digital units. The limits, as he claims, come with the fuzz effect:

“You can’t do fuzzes with it. The fuzz thing, that’s a really tough deal. Some of the old Fuzz Faces aren’t good but some of them are amazing, and who knows why?”

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As Eric adds, the old fuzz pedals, like the Fuzz Face, come with a variety of different components in their circuit. And if you change one with just a slightly different alternative, it will affect the tone:

“I work with a technical personnel called Bill Webb and he’s a real genius. He takes the pots apart and fixes the original pot and puts it back in and so nothing gets changed. I can think of wonderful old Fuzz Faces that were great then two weeks later the pot goes out, then you change the pot and here, I’ll just get rid of the unit.”

He also adds:

“They’re the most fickle pedal ever made but within that they’re the most magical when they’re right. And I worked with Dunlop and we spent two years designing the [signature Eric Johnson] Fuzz Face and we got close. I actually use it some, but it’s not easy.

Dunlop Eric Johnson Signature Fuzz Face Demo

“We made a lot more headway when we degraded the pots and the wires. We started off with better parts and it just started terrible.

“So I think part of it is really hard to figure out, it’s just a mystery a little bit.”

The fuzz is, essentially, a distortion effect. The only difference is that we have extreme clipping where the original sine curve of the unprocessed signal turns into a square-shaped one. The resulting tone is really “dirty,” dynamically compressed, and comes with a lot of additional harmonic content that results in a very unique tone.

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The old-school cases of such distortion were more errors than controlled efforts and this could probably be a reason why it could get so complicated to create it in a super-controlled environment.

Back to the Neural DSP Quad Cortex, Eric Johnson isn’t the only one to reveal that they’re transitioning to using one. In a recent interview, Megadeth frontman Dave Mustaine was asked about why he decided to switch from traditional-style rigs to the Quad Cortex. He explained:

“Well, let’s be honest about what the Neural [DSP Quad Cortex] is. It’s quite an incredible piece of machinery. And I stopped using Bradshaw long time ago for a reason. And I went over to Rocktron. And we were using Rocktron and then we switched over to Furaman.”

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“And as we did that, we started to narrow down all the extra peripheral gear. All of it was rack-mounted, but still, it was a lot of extra stuff in the signal path that you don’t really need and you don’t really want.”

“So you try and get that sound out of the amp. Make sure that the guitar’s got a good sound too. Because if the guitar sounds like a dog, all you’re doing is polishing a turd. You’re not going to really have sound that you’re going to love hearing.”

Photo: Ejmerch (Eric Johnson 2017 ©John Bland)

  • David Slavkovic

    David always planned for music to be nothing more than a hobby. However, after a short career as an agricultural engineer he ended up news editor at KillerGuitarRigs, senior editor at, as well as a freelance contributor to online magazines such as GuitaristNextdoor and brands like Sam Ash.