Testing the Positive Grid Spark Mini amplifier - The next size up — I'll take it!

Features

The Spark collection of amplifiers from Positive Grid is designed for guitarists and bassists. When we tested the smallest of these, the Spark Go, we were pleasantly surprised by the sound quality, given its minimalist dimensions, and by the user interface and modeling offered by Positive Grid. The Spark Mini is identical in many respects, but its dimensions of 147 × 123 × 165 mm (5.76 × 4.84 × 6.49 inches) and weight of 1.5 kg (3.3 lbs.) make it a compact amp, although it can’t fit into a guitar case as its little brother does. Like the Spark Go, the Spark Mini is covered with a thick textured vinyl, which, in addition to giving it a finished look, provides protection against the hazards that an amp destined to be transported is vulnerable to. On the main face is a grille that can be easily removed to reveal a pair of 2-inch speakers responsible for converting the 10W of power the Spark Mini can deliver into sound.

The section dedicated to settings is brief, with a mono instrument input and three knobs: Preset, Guitar and Music. LEDs indicate which preset is currently in use and the status of the power supply and wireless connection. On the rear of the amp, you’ll find the power button, Bluetooth and a USB-C socket for recharging the 3000 mAh battery or connecting to a computer. Two 3.5 mm stereo jacks, Aux In and Phone/Line Out, complete the picture. It takes around three hours to fully recharge the battery, to reach an autonomy of around six to eight hours, depending on use. Furthermore, Positive Grid doesn’t mention the possibility of changing the battery once it’s worn out. However, as you can see from the photos, the mounting screws on the rear of the amp are easily accessible. We can also take comfort that the battery should keep its best shape for at least a few years under moderate use.

Before continuing our test, let’s note that the Spark Mini is designed in the USA, but manufactured in China. It’s hard to fault it for build quality, as the overall package seems solid. The retail price is €215/$229.

A versatile and practical amp

As we saw earlier, there are few controls accessible on the amplifier. In fact, the Spark Mini is designed to work in tandem with the Spark app that runs on Android and iOS devices. The application doesn’t seem to have evolved much since I used it for my Spark Go review. The main screen gives access to preset editing. A preset can have a maximum of seven blocks derived from a catalog of 33 amplifiers and 43 effects pedals. It’s important to remember that we’re in the digital domain, and it’s highly likely that the list will grow over time. In any case, Positive Grid provides all the classic models usually found when talking about amp and effects simulation. The reference names have been reworked, but the avatars are very carefully crafted, allowing us to recognize amp models from Marshall, Bogner, Friedman, Fender, Orange and Ampeg for bassists. As for the pedals, there’s no mistaking the red compressor or the green or gold overdrive. While preset editing is straightforward, with access to a rather comprehensive community catalog, it’s crucial to note that it’s impossible to move the various blocks around. Moreover, they can only be loaded with a specific type of effect. In other words, it’s impossible to consider using two overdrives before attacking the amp, or combining two reverbs. The sound chain must necessarily follow the following pattern :  

• a noise gate  
• a compressor or wah-wah  
• a boost/overdrive/distortion/fuzz pedal
• the amplifier and its speaker
• a modulation effect or additional equalization
• a delay
• a reverb  

For such a compact amp and in the context of conventional use, this is sufficient and relevant. But Positive Grid could have improved its application in the choice of loudspeakers. For now, such an option is non-existent, and each amplifier is de facto attached to a specific speaker simulation that is impossible to customize. It would have been very practical, for example, to have been able to import one’s own Impulse Responses (IR) or, failing that, to create custom amp/loudspeaker pairs using the included collection of models.

In use, I was also bothered by the device’s extreme dependence on its mobile app, particularly for EQing. If you like to play several different guitars, you won’t be able to adjust the frequency curve without having your phone in front of you. I could imagine a “Tone” type knob that can be found on some amps that share similar dimensions, and which allows you to sculpt an overall equalization.

The app gives access to additional features that are quite relevant to everyday practice. With Spark, it is possible to analyze the harmonic content of a YouTube video or a track loaded via the Spotify and Apple Music streaming platforms. In the same spirit, there are two other features called Quick Jam and Smart Jam. The first is a collection of accompaniments consisting of drums and bass (which can be deactivated) in various styles. The second, which I find the most interesting, lets you play a chord progression, which the application then analyzes to suggest different accompaniments. By the way, unlike the harmonic tracking of music tracks imported from YouTube, Spotify or Apple Music, the app can detect four-note chords and isn’t limited to triads alone.

Here’s an example of me playing with an automatically generated accompaniment on a chord progression :

1 – Smart Jam

00:0000:23

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The Spark Mini can also record in several ways. The first involves using the app to film yourself. Image and sound are automatically synchronized. In the age of social networking, this is an excellent idea. The second option is to use the amp as an audio interface via the USB-C. When testing the Spark Go, I encountered numerous stability problems with the ASIO drivers supplied by Positive Grid. This time, on the same computer, no more worries! Everything worked immediately, with no dropouts and negligible latency. Nevertheless, recording is restricted to a sampling frequency of 44.1 kHz. Finally, it’s possible to output a signal through the Line Out, which also serves as a headphone jack, and the result is entirely satisfactory.

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Here are two extracts recorded using the audio interface function and dedicated ASIO drivers:

2 – Enregistrement en USB

00:0000:22

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• 2 – Enregistrement en USB00:22
• 3 – Enregistrement en USB 200:31

What about the sound?

Here are a few extracts recorded using a Shure SM57  microphone:

4 – Clone Drive + American Deluxe + Rev Ambient

00:0001:02

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• 4 – Clone Drive + American Deluxe + Rev Ambient01:02
• 5 – Optical Comp + AD Clean + Room Studio A00:24
• 6 – Blues Boy + Plate Short00:32
• 7 – American High Gain + Digital Delay + Holy Grail00:30
• 8 – BE 101 + Rev Chamber00:30
• 9 – Red Comp + Tube Drive + TreadPlate + Classic Plate00:21
• 10 – Hammer 500 + Digital Chorus00:13
• 11 – LA Comp + Black Op + RB-80000:18

The Mini offers a less boxy sound than the Spark Go, with a more pleasing response in the lower end of the spectrum. The format and power also make it more versatile for uses other than solo practice. For example, it could be used to accompany a duo. As for the simulations, they remain the same and are successful, as a whole. They also have the advantage of covering a wide range of sounds. Of course, playing sensations are anything but “organic”, but the amp reacts correctly to the instrument’s dynamics, and playing with the volume knob is entirely credible. Once again, I was pleasantly surprised by the amp’s behavior when used with a 7-string guitar and even a 5-string bass. The sound remains clean and defined.

Conclusion

The Spark Mini is a compact amplifier with excellent build quality and a wide range of sounds. Playing sensations, while not impressive, are entirely credible and respect the instrument’s dynamics. However, we’ll have to be content with the amp’s heavy dependence on its mobile application. The latter has the merit of being pleasant to use and offers functionalities useful for daily practice. Generally speaking, we would have liked to have been able to adjust the equalization of a preset without using our phone, and it would have been nice to be able to customize the amp/loudspeaker pairing more. Nevertheless, the Spark Mini will easily find its place in many situations.