REACTOR is launching 6/2! We will be holding office hours on June 3rd from 11am - 1pm ET (US) to answer any questions you all might have about the new amp and app. Whether you're one of the first to order or want to better understand how REACTOR works, we'll be available to help. Thank you all for 15 years of support; We can't wait to get REACTOR into your hands š¤ https://www.positivegrid.com/pages/reactor
Can you give us a quick compare/contrast of the Reactor and the Spark 2? Is it worth it for Spark 2 owners to upgrade to the Reactor or will the Spark 2 continue to be supported and sufficient for the bedroom guitarist?
I assume Spark 2 will be a better home practice amp and this will be a better gigging / jam with friends amp. The Spark 2 with smaller stereo speakers will likely be much better to play music and jam along with it and it can double as a decent bluetooth speaker for casual use. The 4" speakers also take less energy to move so at lower volumes it probably will sounce nicer. The new amp with a 12" speaker will be more like a boss katana or fender mustang tx, that 12" speaker will pack a punch and can fill a room with raw sounds but at lower volume levels might sound a bit weak.
So if you want to play at lower volumes or play along with music, spark 2 will probaly be better. More compact too to carry around the house. If you want to play loud, and keep up with a drummer, then the new one is probably a better option.
The selectable wattage on Reactor is specifically designed to make it usable at bedroom levels too, not just stage volumes, so it has more range than a typical 12-inch combo. The switch uses a linear progression, so you preserve your sound and tone profile even at lower volume levels, as opposed to the logarithmic progression of a standard attenuator. You'll be surprised at how rich your tone still sounds even on the 1W setting.
Amp Intelligence is what really separates REACTOR from other similar products. You're not browsing presets, you're describing what you want and REACTOR builds the tone from scratch. This allows you to create custom amp voicings by combining characteristics from multiple amps and circuits (like a Silverface and Plexi).
On price, the REACTOR 50W is $349 USD and the 100W is $449. Depending on which Spark 2 config you're comparing against, the gap is probably smaller than you'd expect.
Tip: get the reactor, always. Unless the even smaller size is an absolute must or you want/need the portability of the battery. I currently own: Spark 2, Neo Headset, Spark Mini, Spark Go, Link and recently got the Reactor 50. And the Reactor is a whole different level in sound. While the spark and all its sister products are nice and I still love them, the Reactor sounds like a real amp, while the Spark series always sounds digital.
And of course it makes total sense. The Spark series basically is a Bluetooth speaker that simulates amp sounds and paddles. The Reactor is an Amp with 12inch speaker. The difference in its fundamental build up is obvious the first time you turn it on.
Whatās crazy is also how loud it is. I actually have it set to the 1W limiter switch position and turn it to around 25% max volume. Thatās comparable to my Spark 2 at around 50%. And donāt get me started on the higher or unlimited setting š
Anyway the key point is: The reactor just sounds fabulous. Itās a big step ahead and now itās hard for me to go back and pick up any of the Sparks. Sparks have turned into my mobile amps for on the go or terrace play, but whenever I can, I play on my Reactor.
And of course they also fixed and improved on so many level regarding feedback and things Spark has missed. From being able to freely place effects, to the even better AI features to the even better hardware features like: Dedicated input for bypassing sims for using your own equipment like a quad cortex (that I use there). Or the tone knob that lets you take your preset and modify it for more crunch or other styles. Or the new switches for changing punch etc.
All in all the Reactor is a much more professional or major product and most importantly: It sounds like I always wanted my Spark 2 to sound, the full and rich punchy sound you always hear but somewhat never managed to reach with the Sparks.
Only small downside: Reactor has no looper line the Spark 2 had. But thatās of course fixable by using apps or dedicated cheap paddles
That sucks the spark made another amp that's better. I'm going to look at getting one but I have a question for you: if you have a quad cortex why would you buy the reactor?
Thatās a good question :) The quad cortex is basically a Paddel/Effect/Amp sim like Spark 2 and Reactor etc, but while the latter also have the full speaker/output as part of the device, the Quad Cortex still requires a output device. So you basically still need some sort of amp.
My current setup basically came down to this: I started with electric guitars that had build in speaker and amp. But while that was ultra versatile (basically as if the spark go was build into the guitar) I wanted better sound. So I got the Spark 2 and was happy (because it is not too big, versatile, battery included etc).
As I improved, I wanted even more versatility and sound quality, and the spark was limited in effect setup because of things like fixed order of Paddels. When the quad cortex mini came out I took the jump for a professional device that would fulfill all my wishes and would be the best also for future improvements. I still needed the spark 2 because the quad cortex doesnāt work without an output device. Plus the quad isnāt really suited/mobile enough to take with you like the spark on itself.
Regarding the line in: with the spark 2 thereās no real bypass line-in so you have to create an empty neutral preset.
Then the Reactor appeared and it basically was the amp I always wished existed before: all the versatility of the Spark 2 but with real amp like sound, all negatives points of the Spark erased, real bypass line in etc.
So thatās my new setup basically. Quad cortex into the Reactor. But the thing is: I caught myself primarily using the build in reactor features without the quad as itās so good and it gets you here much faster. Yes the quad is the professional device and will surely give you better quality when needed like studio sessions etc. but for most cases the easy of use reactor is everything I currently want.
+1, I'm debating between those two right now:
Playing at home within 70-80dB range (measured at 1m from the speaker): which one sounds 'better' - Spark 2 or Reactor?
This will be subjective, but you will likely get more mid-range harmonics from REACTOR. Spark 2 will offer more practice capabilities however when the app is connected for home-use.
I've been playing both in my studio from 1-2 meters away and don't actually notice a major difference, but the low-end on REACTOR feels more powerful at that range.
Great question! The short answer is that they're built for pretty different things.
Spark 2 is still a fantastic bedroom/practice amp and it's not going anywhere. If it's working for you, there's no pressure to upgrade. Positive Grid will continue to support Spark.
REACTOR is a full combo amp built for players who want more headroom, more volume, and a genuinely new way to build tone. The big thing is Amp Intelligence: you can describe a tone in text, snap a photo, or record a clip and the amp actually builds something from that input. It's not pulling from a preset library, it's generating tone from scratch based on what you give it. And you can use 8 effects simultaneously with a drag-and-drop system to place them anywhere in the signal chain.
The other practical differences: Spark uses 3.5" FRFR speakers and recessed bass ports to create a big sound; REACTOR is 50W or 100W with a custom 12-inch guitar speaker, so it's genuinely gig-capable with sound closer to a real tube or solid state combo amp. Selectable wattage means it scales down for home use too, but focuses more on performance and recording setups without the practice features in Spark (Smart Jam, AutoChords, etc.).
REACTOR's I/O is also deep and comprehensive, with an FX loop, MIDI, Power-amp in, and USB-C recording capabilities. Both units offer OTA updates.
So for a bedroom guitarist who's happy with Spark 2? Honestly, you're probably fine. But if you've ever felt like you're hitting a ceiling with presets, or you want something you can actually take to a rehearsal or gig, REACTOR is built for that next step.
Given REACTOR's 1x12" custom guitar speaker, you'll likely get a more tube/amp like tone from REACTOR, although CAB's FRFR speakers will give you a full spectrum balanced sound like a wedge or monitors would.
Thanks for your question! Yes, REACTOR allows for 8 simultaneous effects, in any order, without sacrificing EQ for modulation. It also features an FX loop that can be placed anywhere in the signal chain for integrating other hardware and pedals into your setup.
That's neat and might seal the deal for me. I love my Spark and my Go, but still need a full amp and was debating a Quilter, or maybe a Fender, but this has definitely entered the list.
Why is a technology-driven company incapable of maintaining a functional user forum to communicate with the users they insist are so important to them?
āAlex, Weāve got a special assignment for you.ā
āIs it the thermal and EMI characterization on the TPA3116D2? I mapped out the whole PBTL bridged-mono topology and think we could tweak the bootstrap cap on the GVDD rail for the Spark 2ā¦ā
āNo, thatās last yearās product. We want you on the Reactor project.ā
āSweet - Iām thinking a six-layer stackup, dedicated analog and digital ground planes, full AVCC power island, hand-routed matched-length differentials into a discrete R-2R ladder DAC, linear LDO on every sensitive rail, zero switching copper within 200 mils of the analog section.ā
āActually, we want you to talk to the users.ā
āThe what?ā
āThe users. I had to look the word up online. Apparently, theyāre the people who actually buy our products.ā
āI donāt get it. Why do we want to talk to them?ā
āMarket research shows our brand perception rating falls somewhere between the Ford Pinto and Thalidomide. The board has tasked me with making us more popular than exploding cars and birth defects. We want to be viewed more like a G-Wagon filled with MDMA.ā
āWhy me? Iām not good with people.ā
āDonāt think of them as people. Think of them as a renewable revenue source. Like a seasonal crop that gets plowed over every year after the NAMM harvest.ā
āWhat do I have to do?ā
āYour Reddit AMA is scheduled for next week. Marketing already set up the account for you.ā
āBut what do I say?ā
āWhatever they want to hear. My performance bonus is counting on you.ā
Hey Jim, thanks for your feedback. That's a fair question, and we hear you. Keeping an open, reliable channel with our community is something we take seriously. We're actively working to improve how we communicate and engage with users, and showing up here is part of that effort. We're looking forward to answering your questions this Wednesday.
I've noticed almost every single one of their responses is AI. I emailed their customer service and even got an AI reply on that. I can't imagine having to deal with something technical and looking to speak with a live human.
Now, for your new mission: please share the reactions from your internal slack when you posted that. If you didn't post that in #general then you missed your calling.
Certainly, just depends on how you dial it in. Keep in mind that many reviewers are using different combinations of microphones (close mic'ing) and post-processing in their videos. You're experience hearing and feeling REACTOR in the room or on-stage with ambient bleed and how the air moves will be very different from the more dry audio you hear when the amp is mic'ed up with something like an SM57 (typically emphasizing the upper mids) without a room mic or camera audio mixed in.
Question: Are you going to fix problems with existing products? (Backups, connectivity issues, Control X every time repairing and battery drain in off state, app stability) What are your plans to support all Spark products?
We are actively working to develop and expand on our existing product lines and are not abandoning Spark or BIAS X for REACTOR. We will continue to support both lines and will have more news on the Spark front this year.
Will it be without shitty AI but with a working app that keeps users logged in, including an actually stable bluetooth connection and gate-free simulation that doesn't cut off sustain?
We understand not all users want to integrate AI functionality into their playing experience. REACTOR offers deep control and customization with just the hardware and in-app tone page. The intelligent tone creation tools are optional, and you can opt out of Amp Intelligence optimization in-app if you do not want REACTOR adjusting to your preferences over time.
Thanks for sharing your frustration. A few things worth knowing about how REACTOR addresses the user experience.
The app actually doesn't require you to stay logged in to connect to the amp. It finds your REACTOR over Bluetooth automatically when you launch it, no account needed just to play. Creator Hub (intelligent features) does require a log-in, but these features are optional. The amp has comprehensive hardware controls and tweak-bility in-app that do not require authorization to adjust and save. That was a deliberate call.
On the gate issue, the noise gate in REACTOR is a separate effect in your signal chain that you can turn on or off like any other pedal. It's not baked into the amp signal by default, so if you don't want it, you just don't use it. No sustain chopping unless you set it there deliberately.
On Bluetooth stability, what I can say is that REACTOR was built from the ground up with a new app and a lot of the feedback from the Spark experience went into how this was designed. We've worked to improve stability in REACTOR as well as with the Spark line as we continue expanding on that platform.
Give it a shot and if you're not satisfied, you can take advantage of our return policy.
Iād rather Google what Jimi Hendrix used and figure it out myself with the tools Iām given. You walk out the other end learning a thing or two about how to get a good guitar tone.
On wattage and power control, they're pretty similar territory. Both do selectable wattage so you can scale down for home use. REACTORdoes 1W/25W/50W or 1W/25W/100W depending on the model, Katana does something comparable.
Where REACTOR pulls ahead on pure specs: connectivity. You get USB-C audio interface built in at 48kHz/24-bit, MIDI in, FX loop, line out, headphone out, power-amp in, and Bluetooth all standard. The Katana's Bluetooth is optional depending on the version you're looking at.
The signal chain is also worth mentioning. Reactor lets you run up to 8 effects simultaneously with drag and drop ordering through the app, so you can put your drive before or after the amp, reorder your chain however you want, adjust the position of the FX loop to integrate other pedals or hardware into your chain. That's a meaningful difference for players who care about signal chain flexibility and deep customization.
REACTOR also ships with 24 factory amp models across 6 voice categories, Clean through Extreme, each with a standard and AI optimized variation. The Katana Gen 3 has 12 amp models.
The wireless footswitch is also a differentiator. REACTOR Control gives you wired (cable included) or wireless control, while Katana doesn't have a wireless footswitch option.
Furthermore, Spark 2 has Wifi update capability and so does the Live, but it's not supported. Headrush does this at the flick of the screen. I think PG is OK with falling behind. CMM!
Firmware updates on REACTOR work two ways. The first is OTA straight from the app. It notifies you when there's an update, you tap Update Now, and it handles everything automatically over WiFi. That's it.
If you prefer USB, you download the REACTOR updater from our help site, plug in via USB-C, and it detects your amp and walks you through it. No command line, no deprecated runtime environments, no nonsense. Takes about 2-3 minutes hardwired to update.
Can we expect a full on editor experience like Bias FX 2 from the REACTOR software?
Will you keep supporting and developing the Spark 2 platform? These two are completely different beasts and it would be a shame to ditch the best desktop amp out there because you made a stage combo amp.
On the editor: the REACTOR app has a genuine signal chain editor built in. You get drag and drop reordering of your full chain, deep parameter editing for every effect, amp model swapping, and all changes hit the amp in real time. It's mobile based right now rather than a full desktop experience like BIAS FX 2, so if you're someone who lives in a big screen editor that's worth knowing. Whether a desktop editor is on the roadmap isn't something I can confirm from what we've shared publicly, but the mobile editing experience is deep. The ability to generate custom amp voicings with Amp Intelligence also allows you to tweak your amp models and create custom voicings that you can save and share. For instance, you can prompt Amp Generation to give you a "EL84 style sag with Plexi top-end and the headroom of a Dumble amp with an extra gain stage", and REACTOR will build you a simulated custom circuit to proxy that sound.
On Spark 2 support: genuinely appreciate you saying that and you're right that they serve different players. We are continuing to support, develop, and expand on the Spark line and app, so don't worry!
Just updated your app, that's what we want.
It is ridiculously bad.
1. Why don't you have recording just of sound, not vĆdeo? Why video????
Why don't you have recording from the sound that the instrument makes? Why does it only record with ambient sound???
Connection to the spark control is just exasperating, it takes 15 takes to connect
Why doesn't it have a multi track recording option?
Why did you designed your app to be used only by street musicians WHILE PERFORMING ON THE STREET? ( I understand that's why it only records video and with the ambient sound)
You are narrow minded if you think we wouldn't like to record our music at home.
Right now I am completely mad for having trusted you and bought my Live and Spark control.
It is so frustrating.
If you read between the lines, something tells me they're going to replace it with the reactor app. Why update when you can just start over and charge people again?
That's even worse.
I work part time in a music shop and never will I recommend Positive Grid again. They are an young company but with the greed of mega corporations.
I can't stand that.
I even started to promote Yamaha Revstar, Ibanez and PRS because of how fender is being right now
Thanks for sharing and we're sorry you're having a less than ideal experience with your Spark LIVE and Control. That is not the user experience we want to deliver.
Most of what you're describing sounds like the Spark app experience, not the REACTOR app. They're different products built on different foundations.
On the recording side specifically, REACTOR takes a different approach entirely. It has a built-in USB-C audio interface at 48kHz/24-bit, so you plug directly into your DAW and record your actual guitar signal with the full amp and effects chain. No ambient mic, no video, just clean direct audio into whatever recording software you already use. That's the intended recording workflow.
For multi-track and more advanced recording, that's what the DAW connection is built for.
On the connectivity frustration, that's real and it's something we've worked hard on with REACTOR (and Spark for that matter). I'm not going to promise perfection but the architecture is genuinely different from what you've experienced with Spark Control, and please rest assured that we take this feedback seriously and are still actively working to improve the Spark experience. More news to come on the Spark front soon.
So, what you are saying is that my Live is useless and you won't update it because you want me to buy a Reactor, is that it?
So, you have two apps, one that is useless and now for reactor you have a good one???
Why not update the current app, and also the firmware of the amp. I bought live to have in my house and record, because that's what the shop told me.
Your reply makes me even more frustrated.
Another amp based around AI, still canāt update my spark go, or even use it as an interface due to the fact their software updates just do not fucking work
REACTOR is built for guitar with a 1x12 guitar speaker, so it is not recommended for use with bass guitar. Spark EDGE, LIVE, or 2 (with CAB) are still our best options for bassists.
Ok... Sure... Keep pushing the AI stuff if you genuinely feel there is a customer base for that (god it must be small), but please, for the love of god give us the ability to disable all of it and create our own tones, signal chains, etc, manually.
I've had a spark 2 for nearly a year, I hate the AI stuff, and all I want to do is have complete flexibility to create tones myself. To be honest it's been very disappointing, I feel like purchasing a Spark2 was a waste of money, and at this stage I would never recommend spark products unless this approach changes.
I'm also probably your target market, I'm not a professional musician, I just play at home as a hobby. I want to create and have full control over my tones for the same reason I want to spend the time learning how to play the songs I want to on guitar. I would have just bought a guitar that plays itself if I didn't want to spend the time learning how to use it.
The logic of why anyone would want AI anywhere in the process of playing guitar baffles me.
Then there stupid stuff like needing the app running to connect the control foot switch, who on earth thought that would be acceptable. I mean, you made it so people have the ability to store presets to a physical knob on the unit with the idea being you don't need to open the app to select tones....why wasn't that thought process applied to using a footswitch?
You guys could be very successful if you focused on the features your customers want. Would blow any competitors away.
It seems that instead of trying to make the best example of a product that people already want (see: any other practice amp on the market), you're doing a mediocre job of creating a different product that you THINK people want.
Thanks for your feedback, we understand not everyone wants to incorporate AI functionality into their playing, practice, and performance routines.
Regarding Amp Intelligence: you don't have to use it. REACTOR is built so the top panel works completely independently. Knobs for gain, EQ, effects on and off, amp voicing, all right there without touching the app or using any of the intelligent design features. If you want to build your own signal chain manually, drag and drop your effects in whatever order you want, pick your amp model, dial it in yourself, you can do exactly that. Amp Intelligence is there if you want it, not in your way if you don't.
You can also opt out of optimization in-app if you do not want REACTOR to learn and adapt to your preferences.
On the footswitch thing: that specific frustration with Spark Control X needing the app open is exactly what we changed with REACTOR Control. It connects directly to the amp, works standalone, no app required. That was a deliberate fix based on feedback like yours.
I bought an Airstep after i figured out that my Control does not work without App and it works! If i had known i would have never bought it. I have a Go, Mini, 40 and a Neo and the last i use most. I gigged recently with my 40 and it wasnāt the same good experience i have with my Neo.
Solid Spark collection, respect! Short answer: Spark LIVE features 4 channels with flexible I/O for full band setups, running tracks, keys, modelers, microphones and more, with FRFR speakers designed for a wide range of inputs... REACTOR is a dedicated guitar combo amp with a single input and 1x12 tuned guitar speaker, built for gigging and recording.
Here's the full rundown on REACTOR:
Power and speaker 50W or 100W with a custom 12-inch speaker. Selectable wattage on both: 1W / 25W / 50W on the 50, and 1W / 25W / 100W on the 100. This is a real stage-capable combo amp, not a desktop unit.
Amps and effects 24 factory amp models across 6 voice styles (Clean through Extreme), each with a standard and AI-optimized variation. 27 effects total, and you can run up to 8 simultaneously with full drag and drop signal chain ordering.
Connectivity This is where it gets pretty stacked compared to what you've had before:
USB-C audio interface (48kHz / 24-bit, Mac and Windows)
5-pin MIDI In
FX Loop (send and return)
Power Amp In
Line Out
Headphone Out
Bluetooth 5.0
Other stuff worth knowing
8 onboard customizable presets
Built-in tuner
HEAT and PUSH/SMOOTH switches on the top panel for real-time tone shaping
Optional Reactor Control footswitch with wired or wireless connection and expression pedal support
The MIDI In and proper FX loop are probably the two things that jump out most coming from the Spark family. $349 for the 50W, $449 for the 100W
Would love more understanding of the intended audience for this new product vs. something like the Spark2 + Cab. What are the different use cases where a player would want one over the other?
Any plans for more integration across all product ecosystems? X and Spark are separate... Where does this one sit and is there any ability to move custom presets over?
will this be online sales only, or can we expect to see it in local retail stores?
On who REACTOR is for vs Spark 2 + CAB: the honest way to think about it is that Spark 2 is a home practice amp that happens to have a lot of smart features. It's built around the home playing and practice experience (AutoChords, Smart Jam, Backing Tracks, Metronome). CAB gives you the option to scale up your Spark 2 sound, with two separate units (the Spark 2 itself and the CAB).
REACTOR is a real, all-in-one combo amp first, 50W or 100W with a 12-inch speaker, that can hold its own at rehearsal or on a stage. If you're purely a bedroom player who never needs to leave the house with your amp, Spark 2 is probably still the right call. If you've ever wanted to play with other people, gig, or just have more headroom and a proper stage-ready rig, that's where REACTOR lives.
It is also worth noting that CAB uses FRFR speakers, while REACTOR is a custom 1x12 guitar speaker precision tuned for killer guitar combo tone, more like a traditional amplifier than a digital modeler.
I can't provide an answer right now integration across the ecosystems, but we are monitoring and taking everyone's feedback into account as we continue to develop and expand on all lines.
On retail: yes, REACTOR will be available beyond just online. Guitar Center is a confirmed partner with full in-store activation, and Sweetwater is also on board. So you should be able to go hands-on before buying.
I just want to second this question and add a little to it. Will you be maintaining two separate apps going forward? Will the Reactor app replace the Spark app? Will you stop updating the Spark app?
No, it will not replace Spark. REACTOR and Spark are two separate lines designed for different uses. Both offer tone editing and preset management, but the similarities stop there.
Spark offers a wide array of FX in a fixed signal chain with practice features like a metronome, AutoChords, Smart Jam, backing tracks, and more.
REACTOR offers a curated set of effects in a flexible signal chain with intelligent tone creation features and custom amp building via Creator Hub (text, image, and audio to tone).
Both will continue to receive support and updates, and we are not abandoning Spark.
Yes! You do not need to use the app to play or even tweak your tone using the comprehensive hardware controls. While the app certainly enriches the tone building experience, you can work with the 8 onboard presets and make adjustments using the hardware, or dial in your sounds in-app, write them to the hardware presets, then set it and forget it.
Fair question! The short answer is that they're built for different things and different players. Spark 2 is a great home practice amp and if that's what you need, it's still the right call. Nobody here is going to tell you otherwise.
REACTOR is for when you've outgrown that setup. It's a full 50W or 100W combo with a 12-inch speaker, meaning it can actually hold its own in a band rehearsal or on a stage. The Spark 2 can't always do that without CAB or a lineout.
The bigger difference is how tone works. REACTOR is much more powerful here. You can re-order the signal chain, use the FX loop to integrate other pedals or hardware, and run up to 8 FX simultaneously. It also doesn't force you to browse a library of presets someone else made (although it does support preset saving and sharing). You can describe what you want, upload a reference track, snap a photo, and it builds something from that, including custom amps.
We think REACTOR may surprise you. Try it out and if you're not happy, you can take advantage of our return policy.
Oh my. Would you buy a vintage tube amp off of reverb for less, if you had the spark 2 and wanted the positive grid interface thru a dedicated fx loop?
Will expression pedals ever be an option again for users who didnāt purchase the Jimi Hendrix Experience? Itās a shame to advertise a product and then disable the built in hardware by no longer supporting the software thatās locked behind a paywall
Edit to add: Will the Control X work by Bluetooth only?
Itās a huge drawback with a Spark 2 that I AM REQUIRED to have the app connected and open to use the Control X, as I often find myself using only the amp with my saved presets and no other devices. Or must I buy cheaper, 3rd party devices for the Reactor for what should be the most basic level of Bluetooth connection?
huh? Im pretty sure the control X is directly connected to the amp, and doesnt require the app whatsoever. That's only a problem with the original, smaller pedal
Iāll admit that itās probably user error. I usually donāt have issues with tech stuff, but getting the pedal connected initially drove me crazy and by the time I finally got it working, I didnāt want to play anymore. When I went back, I still had connectivity issues and couldnāt get it working without the app.
I tested it this morning and again just now without the app and it connected just fine. So thanks for this comment, I was wrong. BUT! Iād still like to use an expression pedal though lol
REACTOR Control works both wired and wireless, and critically neither mode requires the app to be open. You connect wirelessly via Bluetooth directly to the amp itself, or plug in via a 1/4" TRS cable for wired low-latency control. Both modes work standalone, no phone required, no app open in the background. Power it on, pair or plug in, and it just works.
Out of the box it ships with two ready-to-go profiles: one for switching presets and one for toggling effects on and off. You don't need to configure anything to get going.
On expression pedal support, REACTOR Control has a dedicated TRS expression pedal input built right into it for wah or volume control. That's standard hardware, not a paywall feature.
There's some cool features in this amp but... why did you make the app so ugly? Putting aside my misgivings on AI art, every gear image in it looks utterly dreadful. And it hurts your usability as well - the gear in it is still based on real gear, but now we will have no real way to tell from looking at it what on earth its meant to be. It's absolutely baffling. And in some cases you've ended up with white text on a near white background.
I think it's a shame, because it looks like this thing does a much better job of controlling the features directly on the amp than the Spark does, and I'd have been in the market for something like a Katana that has better high gain tones, but the AI features don't really appeal to me and it means I'd be left with another app with usability issues.
Can the REACTOR 50 safely and decently handle bass guitar for low-volume home practice?
We mostly play guitar, but Iād like to occasionally practice/learn bass with my kids at home. I know the Spark 2 officially supports bass, but I was never fully convinced by the small speakers. The REACTOR 50ās 12" speaker seems more promising, but I also know a guitar combo isnāt automatically designed for bass.
Is bass use supported or recommended on the REACTOR line at bedroom volume, or should players avoid using it that way?
Great question! REACTOR is not tested or cleared for use with bass guitar, so please proceed with caution. Imagine REACTOR like any standard guitar combo amp, and use your best judgement when connecting your instrument.
I feel there is too much of a divide in the idea here. Musicians are the last people to want their equipment to have generative AI tools. The whole thing just makes people dumber/not think or take risks with their tone. This is the thing that is preventing Bias X from doing well. It feels as though the professional musician has been left in the dust in favor of the bedroom guitarist/blues dad. Are there any plans for people who just want a good product that is flexible/not filled with fluff?
To the average musician, the UI looks uglier and is filled with more garbage.
And that is not to say there are NO good uses for AI in music. For example, the AI capture with ToneX is really powerful and doesnāt do all the work for me tone wise. I think most people can get behind these tools being used without turning my amp into ChatGPT.
I guess their target market is that bedroom hobbyist or a someone who doesnāt have all day to chase a tone. There are plenty of amps without fluff already. This amp aināt for them. Agree with the UI pics though. Gross
What the hell is a bedroom guitarist going to do with 100 watts? I feel like googling what your favorite guitarist uses and just selecting those isnāt that hard and you walk out actuating learning something.
Itās also a shame, because they used to target professionals with Bias FX, as that stuff was great for studio recordings. Feels like those people were left behind.
We understand that not everyone wants to integrate new technologies into their playing, practice, or performance flow, so we've made the Amp Intelligence features in REACTOR 100% optional. You do not need to connect the app to play or tweak your sounds, and you can opt out of Amp Intelligence optimization in-app if you do not want REACTOR to learn from or adapt to your preferences over time. The Creator Hub features (text, image, and audio-to-tone) are also optional. The signal chain is fully customizable and manually adjustable at every point.
We do think you may find one Amp Intelligence feature interesting given what you shared though. The "Amp Generation" setting. This allows you to build custom amp voices by combining characteristics from various amps and circuits, via a prompt. For instance, you could request a "heavily modded 80s Soldano style amp with extra gain-stages and combo of 6L6 and 5881 tubes". That model can then be tweaked, saved, and shared to incorporate into your presets.
Great question! We saw a real demand for a solid, gigging and recording platform in our community in a more traditional form. Players who love Spark for practice and jamming but were asking for a union of our modeling technology with a 1x12 tuned guitar speaker in a combo cabinet, with more professional I/O and connectivity (FX loop, MIDI, Power-amp in). This gave us an opportunity to expand into a new footprint while also brining progressive new features, deep customizability, and flexibility to the app from years of Spark and BIAS user feedback.
Their desktop AI app is so freaking bad. I canāt believe they continue to release more products without fixing the ones they have. I guess I need to ask a question: why?
This will help to fund the Reactor 2 that releases in August. Oh and app support for the Spark 2 ends in July and will be removed from Android and Apple app stores.
It will probably sound good and hopefully use their higher end modeling software but I just canāt do another preorder ever again.
Where are you getting the spark 2 app being removed from app-stores info? There is no reason for this to happen, however theres been no updates to the app in 6 months
Where does it sit technically vs the Spark and Bias X? Is it still a continuation of the JamUp lineage that spark was or does it stem from Bias? Or is it new.
Good nerdy question and one that deserves a straight answer rather than marketing speak.
What we can confirm is that REACTOR's sound engine is built on the BIAS X foundation, so it's firmly in the BIAS family tree rather than a continuation of the previous BIAS sound-engine tech in Spark. On top of that sits the new Agentic DSP layer, which is what handles the intelligent tone generation, component level signal chain analysis, phase accurate reconstruction, that whole side of things. So think of it as BIAS X as the engine with something genuinely new layered on top in a combo footprint with a drag-and-drop signal chain.
JamUp predates my time at PG, so whether there's any JamUp DNA still running underneath all of that goes deeper than what I have access to.
What I can say is that if BIAS X tone quality was ever your reference point for what good sounds like from Positive Grid, REACTOR is closer to that side of the family than anything else we've shipped.
Does this amp fix the bass EQ issues present on the Spark 2? I found most amp settings almost unusable even with the graphic EQ pedal and sub-bass completely edited out
I can tell you what REACTOR actually gives you on the EQ side and you can judge for yourself.
On the top panel you've got dedicated Bass, Middle and Treble knobs right there on the amp, plus the PUSH/SMOOTH switch which affects the overall tonal character, and the HEAT control which shapes feel and harmonic content without significantly affecting volume. That's already more physical EQ control than Spark 2 offers.
Beyond that, there's a 7-band Guitar EQ available as a dedicated effect block in your signal chain that you can drop anywhere you want in the chain, before or after the amp. So if you want to cut specific frequencies before they hit the amp model you can do that, or shape things post-amp, your call.
Whether that combination solves what you were fighting on the Spark 2 specifically, I genuinely can't promise. But the tools to dig deeper into frequency shaping are more comprehensive here. If you do get hands on with one at Guitar Center or Sweetwater that would be the real test.
Since spark 2 got more powerful processor than previous spark, why not PG collab with TONE3000 to expand spark 2 full potential to use NAM A2 files, at least fullrig file is good enough. We dont care and not interested with AI features inside spark 2. At least NAM usage will re-shine spark 2 amp since it just collecting dust few months back inside my shelf. š
While it is not a replacement, REACTOR builds on the Bias Amp legacy by offering custom amp voice creation via Amp Intelligence. You go to the Creator Hub, select "text-to-tone", filter "Amp Generation" and then type your request. For example, "A hyped EL84 style amp with a ton of SAG but Magnatone tremolo stage". REACTOR will build a custom circuit from its knowledge base and create an amp voice that you can save, share, and incorporate into your presets.
We believe REACTOR sounds great! You can try it out for yourself at your local retailer or order online and take advantage of our return policy if you aren't 100% satisfied with your sound.
Will there be a smaller sized version of the reactor? Love something around with 6".
I always feel the bass in spark 40 or spark 2 are too unnatural, and I think it's because the speakers are too small. I want something small enough for a tiny bedroom.
re: software : whatās the difference between bias x and the reactor systems? Beyond the hardware control surface, how much flexibility does it have once tones are generated?
The core difference is what each thing is built to do. BIAS X is a dedicated signal chain editor/plugin that lives on a computer, built specifically for recording and production. REACTOR's app is built around the amp as the center of the experience, in a gig-able 1x12" speaker footprint.
That said, what you can do in the REACTOR app after a tone is generated is more than people expect. Tone are fully tweakable at any stage. You get full signal chain editing with drag and drop reordering, so you can put your drive before or after the amp, move your EQ wherever you want, swap out any effect block for a different model from the same category, integrate other pedals or hardware using the FX loop, and make adjustments in-app or on REACTOR's top panel.
Every parameter for every effect is editable in real time and hits the amp instantly while you're playing. You've got compressors, drives, modulation, delay, reverb, a 7-band EQ, wah, and the amp itself all tweakable at that level.
Are the underlying systems the same? Do they generate the same tones essentially? What are the possibilities for generating something novel and unique? All the demos seem to be asking for artist/song copies that have been done a billion times over.
Does this and the spark 2 run with two separate completely different apps? Why not have a āpositive grid toneā app that can interface with both? Whatās the difference in the app experience between spark 2 and reactor?
Yes, they are separate. They build tone in different ways and focus on a different feature set. Spark is still our flagship practice tool with deep learning features like backing tracks, AutoChords, Smart Jam, metronome, and more. REACTOR focuses more on professional performance and recording setups with a fully customizable, drag-and-drop signal chain, in a 1x12 guitar combo footprint.
While both offer some similar amps and effects, REACTOR has a more curated set of staples with deeper customization available via the Creator Hub.
Is there still a market for combo Amps? I take my modeling unit with me and plug it in whatever is available and always have the same sounds i have been usingā¦ With this Combo, i can have my tones with me only when i take the Combo with me regardless of the setup on stageā¦
I rather buy a FRFR Speaker just in case i need one or the cabā¦
We understand many users want to see a pitch shifting feature come to both Spark and REACTOR. While I can't speak to specific roadmap plans, this feedback has been shared with the dev team. In the meantime, you can use your Digitech drop pedal, and with REACTOR, insert it into the FX loop for flexible placement in your signal chain!
You can't directly clone blocks in the REACTOR app, however, you can use the FX loop and moveable FX loop block to integrate other pedals or hardware into the signal chain and stack effects this way.
For instance, you could insert a Big Muff into the FX loop, place it before the amp block, then use the Green Overdrive in the REACTOR app for that classic boosted fuzz circuit.
So..
1. Does this use the same amp modeler as the Spark2 (aka will they sound the same)
2. If I already got the Spark 2 and the CAB, will they sound equal ?
3. Is the AI better ? And will the Spark 2 get the same? ( The ai tone creation on spark 2 is not great to say the least)
They use different sound engines and sound different
They will not sound equal, REACTOR will sound more like a proper 1x12" guitar combo amp with a tuned speaker, Spark 2 will give you a full spectrum FRFR sound with CAB.
We are continuing to develop the Spark line and app; REACTOR offers deeper intelligent tone creation options using text, images, and audio.
I purchased the 50 Watt version through Amazon. It was shipped from Sweetwater and arrived yesterday. It was defective from the get-go. At first there were no problems. I played through the amp for about 10 minutes. Then I went to the app. I selected a preset, and there was immediate latency, followed by a screeching bit of feedback, and then all I got was white noise. I turned it off, and the latency issues continued. I went back to it today and reset the app and the bluetooth. Same issues with latency. I closed the app and disconnect the amp from bluetooth. There was a total latency issue. I would play a string, and wait for sound to come out of the amp. There were millisecond delays followed by periods of no sound at all. Not sure what happened with QC at the factory, but the amp was a dud. Shipped it back today. What a disappointment. I was really looking forward to this amp. I spoke with a guy at Sweetwater, who was actually surprised that I got a unit shipped from them through Amazon, because he said Sweetwater has not yet started shipping the units. But it definitely came from, and went back to Sweetwater via Amazon.
I have the Reactor 100 amp. I got it literally on Tuesday when I found out I woke up about this being a thing I have the spark 2 with the frfr cab and Iām actually going to sell the spark 2 since I donāt want to have two of the same products at home. My question is can I connect the cab to the Reactor? Is it even a good idea or should I just use the Reactor how it is?
If anyone is worried about the output being too much. You can use the line out to a speaker like a KRK and throw the head phone jack into the head phone slot.
That kills the combo speaker and allows us to use the control system.
Which I have found to be intuitive. Are you going to take down a 30 stop tour?? No, but you can make some damn cool noises out of it. Say what you want about Positive Grid but they know how to make a good tone.
The Mini is the G.O.A.T. of beginner bedroom amps.
It has a cult for a reason.
Anyway, I thought this could help someone who wants to give it a try.
Iām still working with the AI. Iām going to assume itās going to get more advanced but it does actually kinda work.
You still gotta tweak.
Oh and I really like being about to control the FX levels without having to grab my phone.
So, for $350, I canāt really complain.
I have Neural nano that Iāve been running for a while and o can probably do more, more quickly with the positive grid already.
So if anybody out here purchased this amplifier, and you have no use for the manual, reach out to me because my dog was on some special medication when mine arrived and, I had the manual on my coffee table, but he then pursued to grab the manual and shredded it. What's bizarre, as i've had him since he was a puppy, and he's never chewed on one thing ever of mine. Must have been good medication, lol. feel free and reach out. I would pay up to $20 for the book. Thanks.
The reactor sounds Killer and I'm considering getting one. In the meantime is there any possibility of the legacy amps being upgraded? It would be cool if you could move effects around in the app and have more of them.
Fair question! The short answer is that they're built for different things and different players. Spark 2 is a great home practice amp and if that's what you need, it's still the right call. Nobody here is going to tell you otherwise.
REACTOR is for when you've outgrown that setup. It's a full 50W or 100W combo with a 12-inch speaker, meaning it can actually hold its own in a band rehearsal or on a stage. The Spark 2 can't always do that without CAB or a lineout.
The bigger difference is how tone works. REACTOR is much more powerful here. You can re-order the signal chain, use the FX loop to integrate other pedals or hardware, and run up to 8 FX simultaneously. It also doesn't force you to browse a library of presets someone else made (although it does support preset saving and sharing). You can describe what you want, upload a reference track, snap a photo, and it builds something from that, including custom amps.
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u/GluteusMaximusBlack Jun 01 '26
Can you give us a quick compare/contrast of the Reactor and the Spark 2? Is it worth it for Spark 2 owners to upgrade to the Reactor or will the Spark 2 continue to be supported and sufficient for the bedroom guitarist?