Positive Grid spent six years building the Spark into one of the best-selling practice amps on the market. The Reactor, announced on June 2, 2026, is the company’s first product outside that platform. Available in 50W ($349) and 100W ($449) configurations, it targets a completely different buyer: the gigging guitarist who wants a 1×12 combo with modeling firepower, a proper effects loop, and MIDI input. The Reactor lands squarely in Boss Katana and Blackstar ID:X territory, but carries one feature neither competitor offers: AI tone generation from text prompts, photographs, and audio recordings.
Amp Intelligence and Three Ways to Build a Tone
The headline feature is Positive Grid’s Amp Intelligence engine. The engineering team analyzed over 200 amplifier circuits, mapping gain stages, transformer sag, bias points, and harmonic response to player dynamics. That data powers three tone creation modes inside the companion app.
Text-to-Tone lets you type a description (“warm Fender clean with slapback delay”) and receive a fully configured preset. Image-to-Tone accepts a photograph of a guitar, a venue, or even a painting and interprets it into tonal characteristics. Audio-to-Tone analyzes a recording and reverse-engineers a matching preset.
Early reviews from Guitar World and MusicRadar found the text mode the most reliable of the three. Typing “Tom Petty” produced a clean Fender tone with appropriate reverb and chorus. Image-based generation proved more novelty than utility: Guitar World noted that showing the app a photo of an Epiphone RD prompted a preset based on a “fantasy Jackson signature model” rather than recognizing the actual instrument.
The Reactor also includes Tone Memory, a system that learns from your preset adjustments over time and refines suggestions based on your playing patterns. Positive Grid claims the personalization improves with extended use, though reviewers have not yet had enough time to evaluate that claim over months of real playing.
24 Amp Models and 27 Effects Without the App
The AI features get the headlines, but the Reactor functions as a fully capable standalone amp using hardware controls alone. The top panel organizes 24 amp models across six categories accessed via a single selector knob: Clean, Warm, Grit, Crunch, Hi-Gain, and Extreme.
Two toggle switches deliver real-time control over playing feel. Push/Smooth shifts between a tighter lead response and a more relaxed rhythm character without changing gain. Heat is a five-position toggle that adjusts harmonics and compression across a spectrum from glassy to saturated.
The onboard effects section covers 27 algorithms including noise gate, compressor, distortion, wah, modulation, EQ, delay, and reverb. Up to eight effects run simultaneously. Physical buttons on the top panel toggle each effect category on or off, and a dedicated FX Level knob controls wet/dry mix without menu diving.
Connectivity Built for Gigs and Recording
The back panel speaks to working guitarists. A series effects loop with separate send and return jacks handles external pedals at the correct point in the signal chain. A DIN 5-pin MIDI input connects standard controllers. USB-C provides 24-bit/48kHz direct recording to a DAW. A 1/4″ line output with cabinet simulation feeds a PA or recording interface.
Wi-Fi handles over-the-air firmware updates and access to Positive Grid’s ToneCloud preset community. Bluetooth manages audio streaming and app control. A dedicated power amp input bypasses the preamp entirely for players who want to use the Reactor as a powered speaker for an external modeler like the Quad Cortex or HX Stomp.
| Spec | Reactor 50 | Reactor 100 |
|---|---|---|
| Power | 50W (25W / 1W modes) | 100W (25W / 1W modes) |
| Speaker | 12″ custom (4Ω) | 12″ custom premium magnet (8Ω) |
| Weight | 23.6 lb (10.7 kg) | 30.6 lb (13.9 kg) |
| Dimensions | 18.1 x 9.5 x 16.5″ | 20.9 x 9.9 x 18.5″ |
| Price | $349 USD | $449 USD |
Both models include three selectable power modes for flexibility from bedroom practice to a full stage volume.
What the Early Reviews Say
Guitar World gave the Reactor 100 four out of five stars, praising the core sound as “a great-sounding combo with some exceptional modeling amp tones” while noting “teething problems with the ambitious artificial intelligence infrastructure.” The reviewer highlighted the high-gain channels as standouts and called the Push/Smooth and Heat switches novel additions to the modeling amp control vocabulary.
MusicRadar scored the Reactor 50 at 3.5 out of 5, calling the effects competitive with anything in the price range but the app interface “confusing and unintuitive.” The consensus across outlets: the hardware delivers on tone quality and build, the software needs refinement.
One shared complaint: the optional Reactor Control footswitch costs $149 separately. For guitarists who plan to use this amp live, that pushes the real cost of the 50W setup to $498 and the 100W setup to $598.
Where the Reactor Fits in a Crowded Market
The Reactor enters a category dominated by the Boss Katana (established since 2017), the Blackstar ID:X (refreshed in 2026), and the Fender Mustang GTX. At $349 for the 50W model, Positive Grid undercuts the Katana 100 MKII by roughly $100 and matches the Blackstar ID:X 100 TVP.
The AI tone generation is a genuine differentiator, even in its unpolished first-generation state. No other combo in this price bracket offers text-to-tone or audio-to-tone functionality. Whether that matters depends on how you prefer to build presets. The Push/Smooth and Heat toggles, by contrast, are immediately useful hardware innovations that no competitor replicates.
Both Reactor models are shipping now through authorized dealers worldwide.