Positive Grid Reactor Combo Amplifier Quickstart Guide
The Reactor 100 and Reactor 50 are Positive Grid’s next-generation digital guitar combo amplifiers for home, studio, and stage, powered by Amp Intelligence (AI). You can play your amplifier right out of the box with its 8 presets and 6 amplifier models accessible from the top panel.
When you connect the amplifier to the Reactor app for iPhone, iPad, and Android, you unlock a world of additional amplifier models and effects. As you’d expect, with the app you can edit, save, and share presets. With the new Creator Hub feature, you can write prompts for Positive Grid’s AI to create custom amplifier models, signal chains, and more.
Let’s get started.
- Positive Grid Reactor Controls & Connections
- Download the User Manuals
- Positive Grid Reactor App
- Positive Grid Reactor Firmware Update
- Positive Grid Reactor Control Footswitch
- Sweetwater Positive Grid Reactor Demo Video
- Positive Grid Reactor YouTube Tutorial Playlist
Positive Grid Reactor Controls & Connections
You can plug in your guitar and start playing the 8 presets on the Reactor right away. Select between the 6 amplifier models and adjust the gain and tone controls. For the effects programmed into a preset, you can turn them on and off individually.
You can access a much wider palette of guitar tones when you connect your amplifier to the Reactor app on your mobile device; we’ll get to that below.
Controls
Positive Grid Reactor top-panel controls.
Power Switch
Turn the master volume knob all the way down before turning on the power.
Input
Plug in your guitar here.
Master Volume
Sets the overall volume for the amplifier’s output both to the speaker and to the headphones.
Bluetooth & Wi-Fi Indicator Lights
These two lights are off when not connected, blinking when in pairing mode, and solid when connected.
Bluetooth is used to connect to the app on your phone and, optionally, to connect to the Reactor Control footswitch (sold separately).
You can also stream practice tracks from your phone to your Reactor amplifier using a second, separate Bluetooth pairing operation.
Learn more in the Positive Grid Reactor User Guide > Bluetooth Audio.
Connecting your Reactor amplifier to Wi-Fi is only needed when the app notifies you that there is a firmware update to install.
Amp
Select between 6 amp models: Clean, Warm, Grit, Crunch, Hi-Gain, and Extreme.
*AI
The “Amp Intelligence” switches give you tonal options on your selected amp model.
- Push has 3 settings that modify the attack response.
- Heat has 5 settings to adjust feel, harmonics, and gain without changing volume.
Bank Switch & Select
The 2 buttons let you select from 2 banks of 4 presets, for a total of 8.
Amp Controls
Gain, Bass, Middle, Treble, and Master let you adjust your currently selected amp model.
FX
There are 6 buttons to engage effects blocks in the signal chain of each preset: Gate, Compressor, Overdrive, Modulation, Delay, and Reverb.
Tap a button to select its effect. Adjust its Level with the knob.
For time-based effects, use the Tap button to set the tempo.
Hold down an effects button to turn it on or off.
You can also turn effects on and off using the Reactor Control footswitch unit, sold separately.
Using the app on your phone, you can select from a variety of different effects within each block and program each effect’s parameters.
Connections
Positive Grid Reactor back-panel connections.
Bluetooth Pairing Button
Tap this button to put your amp into Bluetooth pairing mode.
Power Control
Select full wattage (100 watts or 50 watts, depending upon your model), 25 watts, or 1 watt.
Foot Control
Use the Reactor Control jack to connect the optional Reactor Control footswitch unit with a TRS cable rather than Bluetooth.
Connect a MIDI controller to the 5-pin DIN MIDI In port.
There’s a table of MIDI control change and program change commands in the Postive Grid Reactor User Manual > MIDI Control – Commands & Setup.
Power Amp Input
Use a TS cable to connect an external modeler or preamp. The Reactor bypasses all internal amp modeling and effects and becomes a “clean” power amp and speaker. Only the master volume functions to control the power amp.
Output (Line Out, Headphones)
Connect Headphones with a 1/8-inch plug. (Turn the master volume knob all the way down first.) The speaker output mutes automatically.
Connect a 1/4-inch TS cable for a Line Out to your mixer, interface, or monitor at fixed line level.
FX Loop
Connect to a pedalboard with external effects using 1/4-inch TS cables using the Send and Return jacks. Using the Reactor app, you can insert the effects loop at any position in the signal chain and set the level.
USB-C & the Positive Grid Reactor as an Audio Interface
Connect a USB-C data cable to your computer to use the Reactor as an audio interface with 1 output and 2 returns. (The Reactor signal chain is monaural.) On your Mac or Windows PC, you can select between 16-bit/44.1kHz and 24-bit/48kHz.
If you are on Windows, then you must first download and install the Positive Grid Reactor ASIO driver for Reactor. Select your product and your download from the Positive Grid Download page.
Download the User Manuals
The Positive Grid manuals are available as webpages, but you can also download PDFs for reference. On the Positive Grid Reactor Download page, download the manual for the amplifier and for the phone app.
Positive Grid Reactor App
Positive Grid Reactor app
With the Reactor app for iPhone, iPad, and Android device, you can select between a wide variety of amp models and effects that you can’t access with the Reactor amplifier’s controls. Using the app, you can adjust the effects parameters in detail. You can create and store all the custom presets you like within the app and then load 8 at a time into the memory of the amplifier.
The app also provides Positive Grid’s groundbreaking AI function, the Creator Hub, which you can use to generate complete presets based on prompts describing the sound you want. You can do this by writing, speaking, or having the app analyze audio recordings or even photographs.
Thus, you can create presets by the traditional method or the AI method. Any presets you save can be further refined and edited using the parameter knobs on the app.
Learn more in the Positive Grid Reactor App User Guide.
Download the Reactor App
On your iPhone or iPad, download the Positive Grid Reactor app from the Apple App Store.
On your Android device, download the Positive Grid Reactor app from the Google Play Store.
Connect Your Reactor Amplifier to the Phone App
With Bluetooth enabled on your mobile device, launch the app. When you turn on the power on your Reactor amplifier, it will be in Bluetooth pairing mode. The app will automatically detect your amplifier.
Register Your Purchase
You’ll be prompted to register your purchase when you log in to your Positive Grid account or when you create a new account. You need to be logged in to your account so you can download and share presets from Positive Grid and use the Creator Hub AI features.
Tone
On the Tone page, you can call up a preset and edit it by choosing an effect for each block and setting its parameters.
Effect Blocks
The default order of effect blocks is:
Gate > Compressor > Overdrive > Wah > Equalization > Amp Model > Modulation > Delay > Reverb > External Effects Loop
You can freely rearrange the order of blocks by dragging and dropping.
Tap on an effect block to pull up the parameters for the selected effect. Tap on the name of the block to see a menu of different effects; you can choose one to replace the current selection. For example, under “Modulation” you can choose from Analog Chorus, Cloner Chorus, Classic Phaser, and Jet Flanger.
Amplifier Models & Speaker
While the Amp knob on the Reactor amplifier has 6 positions, there are 24 amp models to choose from in the Reactor app. With the Creator Hub feature, you can design additional custom amp models.
When you tap the Amp effect block, you can choose your model and see the same knobs available on the hardware for gain, tone controls, and master. Adjust them on the app and save them to a preset.
NOTE: Every amp model and preset on the Reactor is designed to use the Reactor’s power amp into the physical 12-inch guitar amp speaker. If you use headphones or the Line Out or record digital audio over USB, then the Reactor adds a fixed virtual speaker-cabinet simulation to the output that matches the sound of the physical 12-inch speaker.
Creator Hub
The Positive Grid Reactor app’s Tone Creator Hub page.
On this page, there are 4 ways to create tones with AI prompts:
- Describe It
- Use a Photo
- Use a Song
- Fix My Tone
Here’s Positive Grid’s short demonstration of these tools.
Positive Grid: Reactor – Creator Hub Walkthrough
ToneCloud
On this page, when logged in to your account, you can access the Positive Grid ToneCloud to download new presets, organized by category.
Settings
On this page, you can log in to your account, use the amplifier’s tuner on-screen, and access Positive Grid’s video tutorials and support pages.
If you have a guitar with high-output pickups, select Hi-Z mode.
You can also choose whether to mute the speaker when Line Out is connected, configure expression pedal settings, and perform a Factory Reset to restore the presets and settings to their default states.
Here’s Positive Grid’s brief tutorial on using the Reactor app.
Positive Grid Reactor App Overview Video
Positive Grid Reactor Firmware Update
From time to time, Positive Grid will provide a new firmware update that will fix bugs, may add new features, and will ensure compatibility with the latest version of the Reactor app. When you first connect your Reactor to the app, it will check online and notify you if a firmware update is needed.
The firmware update is accomplished wirelessly. The procedure requires you to use the app on your mobile device, which is already connected to the internet and connected to your Reactor amplifier over Bluetooth, to configure the Reactor amplifier to connect to your Wi-Fi.
When the app notifies you of an update, follow the instructions on-screen and enter the password for your Wi-Fi.
Be patient during the firmware update, which will take several minutes. Do not unplug the power or disconnect anything until the app informs you that the firmware update is complete.
Learn more in the Positive Grid Reactor Amp User Guide > Firmware Update.
Positive Grid Reactor Control Footswitch
Positive Grid Reactor Control footswitch.
The Positive Grid Reactor Control footswitch, sold separately, is designed for the Reactor amp. You can connect it using a 1/4-inch TRS cable or through Bluetooth.
You can use the Reactor Control in two modes: to change presets; or to turn effects on and off individually and enable or disable the effects loop.
The unit runs on an internal battery that you can charge with a 5-volt USB-C charger.
The unit can be further expanded with an external expression pedal connected by a TRS cable. The expression pedal can be configured to control a wah effect when present in a preset, or it can control guitar volume.
Calibrate your expression pedal via the Reactor app or by using the buttons on the unit itself.
Here’s Positive Grid’s tutorial on setting up the Reactor Control.
Positive Grid: Reactor Control – Quickstart Guide
Learn more on the Positive Grid Reactor Control support page.
Sweetwater Positive Grid Reactor Demo Video
Here’s Sweetwater’s Nick Bowcott.
Sweetwater Soundcheck: AI-curated Tones from a Combo Amp?! | Positive Grid Reactor 50 & 100
Positive Grid Reactor YouTube Tutorial Playlist
Positive Grid Reactor YouTube Tutorial Playlist.
Click on the image above to go to Positive Grid’s tutorial playist on YouTube, with a growing list of short videos that walk you through various functions with the Reactor amplifier and the app.
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