Positive Grid Spark Pearl review: A high-tech guitar amp that’s easy on the eyes

Even the other parts of the app, while functional, lack some polish. The music tab at the bottom is home to the Smart Jam backing tracks and YouTube videos. These videos cover everything from bland genre backing tracks, to tabbed versions of popular songs, to just plain old music videos that have been analyzed by Positive Grid’s Smart Chord system. Sure, these things are all related, but it’s still a lot crammed into a single place. Especially when there’s a tab dedicated entirely to recording video of yourself playing, a feature that feels tacked on. I also have to say that the Smart Jam feature is kind of inconsistent. While it was decent enough at detecting what chords I was playing and staying in key, the rhythms always felt like they were basically picked out of a hat and I had to adjust what I was playing to match.

The ToneCloud section where users can upload combinations of amps and effects they’ve designed, is similarly messy. Of course, with over 10,000 options uploaded, it would be hard not to be. Still, while you can sort by popularity and browse by broad genre categories, there’s no rating system or descriptions beyond whatever its been named.

Many people will be disinclined to use the app regardless. For some, that’s just not what they want in a guitar amp. Instead they’d prefer to stick to the physical controls and are more focused on the built-in sounds. But let me get one thing out of the way: If you’re not interested in the app, the backing tracks and numerous amp and effects models, you’re better off just looking elsewhere.

Positive Grid Spark Pearl amp

Terrence O’Brien / Engadget

That’s not to say that the controls or the built-in sounds are bad. Just that the real strength of the Spark lies in its flexibility. That said, Positive Grid deserves credit for packing a decent amount of variety into the limited controls on the panel. There are seven amp models immediately accessible: acoustic, bass, clean, glassy, crunch, hi-gain and metal. That pales in comparison to the 30 available through the app, but it definitely covers your basics.

There are also three knobs that add in various modulation, reverb and delay effects. But, this is one of those places where, if you’re skipping on the app you’re missing out. The on-amp controls are basically just wet-dry knobs for whatever virtual pedal Positive Grid paired with that amp sound. If you want to actually change decay times or modulation depth, you’ll need to open the app. At least there’s a tap tempo button on the amp itself.

As far as the physical controls go, my one issue is with the “music” knob. It basically just controls the volume of whatever you’re pumping in over Bluetooth, but it’s very finicky. Finding the right balance between the backing track and the guitar is difficult; just a fraction of a millimeter too far and you’ll drown out your soloing.

Positive Grid Spark Pearl amp

Terrence O’Brien / Engadget

If you want to avoid using the app at all costs, I strongly suggest you use it at least once to build your own custom tones and save them to the four preset slots. This will give you the exact amp and effects you’re looking for without having to reach for your phone every time.

Alright, I’ve jabbered on enough about the app and the features. Now let’s get down to how the Spark sounds. In short: great. I have some critiques that I’ll get to in a moment, but straight out of the box the Spark is pretty impressive. It’s not as convincing as some other modelling amps out there, but it sounds full, rich and warm. And at 40 watts it’s surprisingly loud. The high-gain stuff is especially good. Many modelling amps choke — and hard — when it comes to more aggressive and metal tones. But not the Spark. It can do everything from convincing thrash sounds to sludgy doom metal to chugging nu-metal dissonance with aplomb.

While some of the clean amp sounds can be a touch sharp sounding, I do truly love the Matchless DC30 emulation. Where the Roland JC120 and Fender Twin Reverb models border on brittle, the DC 30 is bright and with just the right amount of bite. Other standouts are the Vox AC30 and Marshall Super Lead 100 which, again, aren’t going to fool a well trained ear but are close enough and sound great in their own right.

The effects also cover a wide range of sounds. They’re all decidedly digital and aren’t quite as solid as the amp models, but they’re definitely usable. The delays are especially solid, though I do wish there were some more out there options — something with some lofi tape warble or shimmers, for instance. The same goes for the reverbs and, well, honestly all the other effects too. They’re all pretty staid. They get the job done, but they’re not gonna wow you.

My biggest complaint about the sound is something you might not even notice at first, but once you do it’s impossible to unhear. And that is simply that the Spark doesn’t sound like a guitar amp. The two full-range speakers inside are deep, bassy and full. When heard on their own, the richness is undeniable. And they do just as good a job at handling music as they do a guitar. But, therein lies the problem: Stereo speakers for playing music and guitar amp speakers are voiced completely differently.

Guitar amps are often more mid and treble focused to help them cut through a mix and get out of the way of the bass and drums. But, even with the bass knob turned all the way down, the Spark still felt distinctly darker and warmer than either my Yamaha THR10 or my Fender Blues Jr, regardless of what modeled amp I chose. Trying to find the right balance on the EQ took a lot of time and effort, but no matter what it couldn’t quite match the snap of my other two amps.

For practicing at home, and playing along with a song from YouTube this isn’t a major issue. In fact, the voicing is kind of a benefit in that use case. But it might prove to be a problem if you’re jamming alongside a bassist and a drummer, or when it comes time to record. And the ability to connect the Spark to your computer via USB and use it as an audio interface directly into your DAW is one of the selling points. So, be prepared to do some serious EQing after the fact if you plan to record with the Spark.