REACTA Board | High-performance custom board that brings DS4 to the next generation

Same shape.

True evolution.

New performance.

Rebuild

Send-in Service

MERKA.G PS5 Dualsense Custom Controller Back Button カスタムコントローラー背面ボタン MG Series Original Design

Same shape.

True evolution.

New performance.

Rebuild

Send-in Service

Looks like a DS4.
But inside, it’s something else entirely.

We kept the shape but completely overhauled the performance. A model redesigned as "the next answer to the DS4."

The familiar feel, with a surprisingly new sense of control.

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What has evolved?

MERKA.G PS5 Dualsense Custom Controller Back Button Paddle カスタムコントローラー背面ボタンクリックトリガーバンパー

MERKA.G PS5 Dualsense Custom Controller Smart Trigger カスタムコントローラー背面ボタンクリックトリガーバンパー

REACTA
The core that leads the DS4 into the next generation.

The exterior remains the same, but the interior has been upgraded to the next generation.
REACTA is a performance core that takes the DS4 to a whole new level of operability.

MERKA.G PS5 Dualsense Custom Controller カスタムコントローラー Smart　Model Smart Trigger クリックトリガーバンパー

Developed by the world-renowned hardware engineer Marius.

The high-performance custom PCB “Marius JDM-5X” is a high-precision mainboard designed exclusively for the DualShock 4 by the globally acclaimed hardware engineer Marius. It minimizes input latency to the extreme, pursuing pure reaction speed and exceptional control precision. As a “competition-focused model,” it has earned strong support from players around the world.MERKA.G provides this JDM-5X through official channels in Japan, ensuring an environment where players can obtain and use it with complete confidence.

REACTA - The board built to keep reacting.

At MERKA.G, we use the JDM-5X as our “REACTA” board. The name combines React + Active, expressing our aim to create a board that continues to react instantly to every input.When integrated into the REBUILD MODEL, the exterior, internal structure, and overall operability are fully optimized for competitive performance. With our uniquely designed front shell, rear grip, and Type-C connector, we achieve a high-level balance of input precision, grip comfort, and response speed.Designed not only for competitive players but for anyone seeking more accurate control, this is MERKA.G’s flagship PS4 custom controller, built with the highest standards.

Disclaimer

This product is a special model provided as part of an experimental development project by Marius. Therefore, you will find it easier to use if you have a basic understanding of the hardware structure and settings.

MERKA.G is an authorized distributor of this product and offers board assembly and additional customization (optional). For the latest information on product usage and troubleshooting, please check the FAQ, which is updated regularly.

*Some issues caused by board-specific behavior or specifications may be outside the scope of support.

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Key settings enabled by REACTA

Polling rate adjustment

Response speed can be optimized in the range of 1000 to 8000Hz.

Stick Deadzone

Finely adjust the internal and external deadzones to minimize input play.

Stick Curve

Customize input characteristics based on the amount of tilt. You can adjust the "character" of your aim, such as linear or acceleration.

*Currently unavailable due to preparation for update.

Trigger Deadzone (L2/R2)

In normal mode (non–click trigger), you can adjust the actuation point distance.

Rear Button Mapping

Models with rear buttons allow you to freely assign inputs.

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How is it different from the original DS4?
Why REACTA is considered “next-generation”

REACTA
Original DS4

REACTA

Ultra-fast response up to 8000 Hz

USB TYPE-C

Precision aiming with TMR Stick

Contactless structure for longer lifespan

Secure grip with the rear grip

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Original

Signal rate around 250 Hz maximum

microUSB

Variable-resistance stick (wears out easily)

Prone to drift over time

Standard shell

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REACTA

Ultra-fast response up to 8000 Hz

USB TYPE-C

Precision aiming with TMR Stick

Contactless structure for longer lifespan

Secure grip with the rear grip

Original DS4

Signal rate around 250 Hz maximum

microUSB

Variable-resistance stick (wears out easily)

Prone to drift over time

Standard Shell

How to get it – How to get REACTA?

MERKA.G PS4 Dualshock4 Custom Controller カスタムコントローラー Smart　Model Smart Trigger クリックトリガーバンパー

REBUILD MODEL

Using a fully functional original DS4 as the base, this completed model replaces the board, shell, buttons, and sticks with brand-new parts.
MERKA.G handles all adjustments and reassembly, allowing you to experience top-tier control performance the moment it arrives.

Detail

Send-in Service

A service where you send in your DS4 and we replace the internal board with REACTA.
You can add only the custom options you need and upgrade it to high performance while keeping costs down.

Detail

Additional custom options

Click Trigger/Bumper

Greatly shortens the travel distance of R1/R2/L1/L2. With a light, mouse-click-like response, it enables rapid tapping and faster, more precise actions. Ideal for FPS and competitive games where reaction speed is essential.

Rear Button

Allows quick inputs without lifting your fingers, enabling intuitive jumps and action commands. The balanced click feel prevents accidental presses and provides stable control in FPS and action games.

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Setup Guide — How to use REACTA properly

When you receive your REACTA controller, please begin by flashing the firmware and recalibrating the sticks. In the current specification, stick settings are tied only to the “connected PC,” so the initial setup and recalibration when switching PCs are essential for proper operation.

This specification is planned to be improved in future updates, but for now, be sure to recalibrate upon arrival and whenever using the controller on a different PC.

1｜Flashing the board

When starting up for the first time, please use the dedicated tool to flash (write) the firmware.

Set up

2｜Recalibration

The REACTA board is dependent on the PC environment in which it is calibrated.
Therefore, be sure to recalibrate immediately after arrival or when connecting to another PC.

*LED and button settings are saved within the board, but stick dead zones require calibration each time.

3｜Operation check

Please check that all inputs are responding correctly and if you have any issues please contact our FAQ page or support.

About updates

REACTA is scheduled to continue to add new features and improve the game.

Check below for the latest updates and tools.

Renew/Update

We will also post new update information on social media (X/Instagram/LINE) from time to time.

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Important Information

The greatest feature of the REACTA board is its native support for 8K polling rate. Because of this, there is no need to use third-party overclocking software. The JDM-5X can be configured through the setup link provided in the FAQ and supports the following onboard settings:

・Remappable rear buttons

・Inner / outer deadzone adjustment

・Customization of stick curve response

As this product uses a custom PCB, the following functions are not supported:

・Console connection ・ Bluetooth connectivity ・ Macro functions ・ Key assignment ・ Vibration motors ・ Touchpad functionality ・ Battery

Do not perform overclocking. REACTA already operates at an optimal 8K polling rate. Attempting additional overclocking may cause instability or even reduce response speed. For the best performance, connect the device directly to the rear USB port of your PC (USB-C to USB-A).

Frequently Asked Questions

What are the benefits of ordering the JDM-5X (REACTA) from MERKA.G?

The biggest advantage of ordering the JDM-5X (REACTA board) from MERKA.G is that you can receive a fully assembled competitive controller ready to play the moment it arrives. When purchasing directly from Mr. Marius, installation requires technical expertise, but at MERKA.G we handle all board installation and tuning in-house. This means customers do not need any specialized work and can start using it immediately.

Furthermore, MERKA.G allows you to combine the board with:

・Click Trigger / Bumper

・Rear buttons

・Original front shell

・Rear grip shell

・TYPE-C port conversion

This enables us to create a fully finished product that integrates MERKA.G’s unique customization features.

Setup Configuration and Update Links

For setup, readjustment, or button remapping, please access the links below.

Setup (TMR Stick):
https://devsetup.mariusheier.com/

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For the latest firmware and update information, please refer to Mr. Marius’s official channel.

Firmware update page:
https://update.mariusheier.com/

Please use the official channel operated by Mr. Marius for update announcements.

Connection method and terminal specifications

This board is wired-connection only. Please use a USB-C to USB-A cable and connect it directly to the rear I/O port of your PC.

It does not support front USB ports or connections through a USB hub, and using them may result in improper operation.

Additionally, MERKA.G’s REBUILD MODEL and Send-in Service come standard with a USB Type-C port.

If you added REACTA board options at MERKA.G, a generic 10-foot (approx. 2 m) USB-A to USB-C cable will be included for connection.

What this board can't do

Because this product uses a custom PCB, the following functions are not supported.

・Console connection ・ Bluetooth connectivity ・ Macro / key assignment functions ・ Vibration function ・ Touchpad function ・ No battery

Why doesn’t MERKA.G use Ginful stick?

At MERKA.G, we use HALLPI’s “TMR Sticks,” which provide tension and operational feel similar to the original ALPS-made sticks. We also tested Ginful models, but found notable differences in center-return feel and overall operation. For this reason, we continue to adopt TMR Sticks to ensure a more natural and consistent control experience.