r/QuadCortex

It look me months to finish this. It's my first Raspberry Pi Pico project.

Features:

- Automatic midi output (aligned with the playback whenever you want it to happen)

- Click output (for drummers IEMs)

- Stereo backing tracks output (for FOA), can output mono from left channel if FOA doesn't have space.

- Dynamically generated click and count-in. The click you hear in the demos isn't an audio track but generated live on the Chrona

- Banks (each bank being a setlist of tracks)

- Fully controllable via two footswitches

- Tempo LED that doubles as an aux button (used to open the menu)

- Expression MIDI support (ramp up and down whatever you want)

- 32GB memory

AI disclosure:

I'm a full stack software engineer and did most of the microcontroller myself, save for asking AI to help me make USB file transfer faster as it kept getting bogged down from RAM use.

PCB and CAD design all my own (from my guitar pedal background)

Desktop app is pretty much vibe coded, directed it feature by feature until I was happy

Can any fellow guitar nerd confirm or deny this? I thought Stephane to be the pedal / tube amp purist, but this seems to be a smart choice.

Shot at Utrecht, August 18th 2026, during the build up for Alcest after Kabbel. The QC is on Neige's side of the stage. Looked like Zero is on QC as well, but Indra used a set of pedals still.

Side note, can we get presets now Neige? 🤣 Say, the Kodama/Eclosion shamisen sim?

What presets would you like to see?

Pretty happy with this but I have no idea how to best leverage the ReAmper with Quad Cortex in a home recording setup?

Kept the mint dust for my picks too

Hi Guys

Since I've had the QC I've tweeked the factory preset "John's amp" to my liking but didn't really change the signal chain.

For the metal rhythm sound, the signal chain is split through 2 different amps which are sent to left and right speakers in stereo. When I practice on my PC I don't have a problem because I have L+R speakers but when I want to practice louder, I have only one FRFR speaker (so, no stereo setup). Problem is, only one amp is heard in that setup.

I thought the signal chain was split into stereo (1), then back together (2) because it's represented that way on the screen (see screenshot https://imgur.com/a/L0L0OHx of the signal chain) but it isn't the case. How can I get all my sound through only one speaker?

I bought a QC mini for its compact size. However, I find the navigation could be better with a midi controller and I want everything be done just by single tap, so no holding, no double tap. I would prefer a compact one, as I still want to keep the board small. And I would like to know what midi controllers you QC mini users are using.

99% of the time I use it at home, I don’t gig but I do jam with others once in a blue moon. I mostly use scene mode and I don’t think I’ll need more than 4 scenes, so scene switching is already dealt with by the QC itself. And I am now looking at the Morningstar MC4 Pro (mostly because of the brand’s reputation and the scribble strips), 2 switches for preset up & down, 1 for tap tempo, and 1 for gig view. Am I overlooking anything? Or is the mc4 pro good enough? Are they any functions that would be beneficial with more switches that I haven’t think of?

I have attached a pic planning the board, I don’t think I’ll need a MC8. I am still deciding between the MC4 and MC6, because I might need more switches in the future? I’m not sure tho? I’m still leaning towards the MC4 tho, so I can fit a Strobostomp (must) and a Drop (will upgrade to the Solar Chug Capo in the future).

Noob question: I’ve never used midi before. Since the QC mini is using 3.5 mm for MIDI, is any 5-pin midi to 3.5 mm cable able to connect the two? During my research, I found something called Type A 5-pin MIDI to 3.5mm TRS, do I have to use specifically this kind of cable?

I am desperate to find a solution and afraid that there is nothing that can be done other than switching to a different system entirely. Very frustrating because I sold my amp and pedalboard that I loved to fund this.

Since I got my QC I have had this noise issue that when and only when I play, there is an awful noise (Shown in attached video), especially on high gain set ups (still present on clean though)

I have been through Sweetwater support several times now, even contacted Neural DSP and tried many things, including having a 2nd unit sent to me to no avail.
A secondary issue I am having is getting a very weak signal when trying to play into DAW, when I try to set input and getting the meter right, I takes a LOT of added DB to get a good reading (little yellow, not clipping). Additionally, when I turn up input it makes the noise issue far worse.

Some of the things I've tried so far include:
Gain staging
2nd QC sent from Sweetwater
Different Cables
Headphones
Testing unit at a different house
Having unit away from electronics
Plugging unit directly into Yamaha HS8 monitors
Global EQ
Noise Gates
Trying 3 different instruments through it (PJ Bass, Strat, 335)

What gets me is playing a plugin through scarlett 2i2 gives me perfect tones that have that same issues on QC plugin presets.

The only success I've seen in getting rid of the noise was when playing bass, rolling off the tone pot would get rid of the sound, but this doesn't help much at achieving desirable tones.

EDIT: I don’t believe it is an issue with the QC. I have made good progress in mitigating the issue.

My primary set up is QC->Mixer->Monitors. A major issue I identified was having the mixer too hot when trying to achieve desired volume. Having a hot signal there would amplify the bad noise when making adjustments to QC IO settings when trying to get a good signal. Because of this, a disproportionately weak signal was being pushed hard via monitors/mixer not the QC.

After configuring my levels I’ve been able to isolate the issue to amp blocks particularly high gain/low headroom amp models. My approach to dealing with the remaining noise is to implement a side chained gate, input gate, and a gate after the amp.

I still feel a little unsure about everything because I’d imagine that QC presets usually don’t give people these issues right out of the box. I am new to amp modeling though and there’s lots to learn. I’ve always been a plug and play or set and forget kind of player with traditional amp/ pedal board set ups, but I think the QC truly shines when you build and configure your own presets.

Trying to download a couple things from Cortex Cloud on the iPhone app but can't figure out how to connect the phone to QC.
Is it literally just a USB-C cord?

Hi everyone. Some of you might know me from the NDSP Discord over the years where I go by the name Beggars. I've been working on a platform on and off for over 13 months by myself as a side project (I'm a full-time software engineer by day), secretly hoping that NDSP would release the highly anticipated marketplace we've been waiting for, for like 5 years now. Alas, it's not out and I'm not sure it's coming.

I was in the first batch of Quad Cortex orders here in Australia and it has been rock solid since purchase all those years ago. But as we all know we're still waiting for some of the functionality revealed years ago like the marketplace.

If you sell Quad Cortex presets or captures, delivering each order through Cortex Cloud is annoyingly manual. You have to sign in, add the buyer as a friend, wait for them to accept, then share the preset/capture, etc.

Preset Bridge connects to your store and handles that process automatically. If the customer hasn’t accepted the friend request yet, the delivery stays queued and tries again later. It currently works with Shopify, WooCommerce, or a generic webhook.

Since Cortex Cloud doesn’t have a sharing API, the service needs the seller’s account to complete the delivery. Credentials are encrypted, never written to logs, and can be deleted whenever you like. I know that still requires trust, so I’m happy to answer questions about how it works. I don't even know if anyone has a need or want for this. I sell presets and manually sharing them was getting to me, so this was more built for myself first and then after testing it myself by dogfooding it, it's finally ready for release.

It’s a fairly niche tool, but manual delivery gets old quickly when you have more than a few orders. I’d be interested to hear from anyone selling presets or captures. It handles the full flow and is more aimed at preset sellers than general QC users.

So I am not sure if anyone has a need, want or desire for this. But it's online here at https://presetbridge.com/ if you want to check it out. And apologies to the mods if this type of post isn't allowed, I just wanted to share something I've been trying to release for a long time now and finally did it.

Also, full disclaimer this isn't associated with Neural DSP or any of its subsidiaries whatsoever. It's just someone who owns the QC and wanted a better way to sell presets. So obviously lots of asterisks for this.