Positive Grid Spark Mini amp review: Fantastically portable with some great tones, but limited in some ways compared to its big brother

As a guitarist, I was more than psyched to get a chance to review Positive Grid’s Spark Mini for TechHive. Of course, that was primarily as a portable Bluetooth speaker, which is one of its neater aspects.

I did cover the battery-powered unit’s intended primary role–practice amp, but not in great depth. Neither did I go at length about using the amp for recording–something its integrated USB 2-in/2-out interface and auxiliary line-level output should make it great at.

“Should”, because recording (or not in the long run) proved so exasperating, I had to explain why somewhere. Where better than my own site? 😉

Note, as of 11/20/22, I’ve found that this amp is aces for direct recording of bass. The RB-800 amp model is fantastic. Also, Positive Grid solved the low output problem discussed below.

As of 6/01/23, you can now also connect via USB and still use the Android app to change presets. Alas, there are some volume issues so I still use the line out.

Specs and design

The Spark Mini measures approximately 6 inches tall (add a bit for the control knobs and feet), by 5 inches wide, by 5 inches inches tall and weighs in at a bit over 3 pounds. It sports twin 2-inch speakers driven by a 10-watt class D amp. There are preset, guitar volume, music (media) volume knobs as well as a 1/4-inch phone input on the top.

On the back of the speaker are a 3.5 mm headphone/line level output (more on that soon), a Type-C USB port for charging and computer interface, as well as the power and Bluetooth pair buttons. The status light for these are on top.

There’s also a handy captive leather carrying handle and a replaceable tweed speaker grill. The whole deal is covered in Tolex as every amp should be.

Recording problems

There were two major issues with the Spark Mini I was sent. Keep in mind that it’s a pre-release version and may be fixed by final release, though I was told it was the exactly the same as the upcoming shipping units.

The problems go hand in hand. The lead issue is that with an Android device (iOS is apparently fine), you can’t use the USB interface and Bluetooth at the same time. This means when recording via USB you’re effectively stuck with the four presets available on the dial.

There are no physical tone controls on the amp to tweak the treble, mids, bass, etc., as there are on its larger Spark 40 predecessor and other practice amps. If you’re not happy with what’s coming in over USB (and I often wasn’t), you have to disconnect, reconnect via Bluetooth, make whatever changes you think you need, disconnect from Bluetooth, then reconnect via USB–a total pain in the you know what. And no, the speaker doesn’t sound the same as the USB signal.

*With no tone controls, you must use the app to adjust tone. The Android app makes this very difficult as you can’t connect with Bluetooth and USB at the same time.*

Because of this, I decided to use the auxiliary line level output which does function while you’re connected to the Spark Mini via Bluetooth. Theoretically, I could then use the Spark app to tweak whatever I wanted. That’s where I ran into issue number two.

The method did indeed work, and I had no problem with the quality of the sound emitted by auxiliary output–there just wasn’t anywhere close to enough of it. The levels showing up on my interface and DAW were less than -18 dB–barely audible compared to everything else. Unless I turned down all the other tracks, I couldn’t hear what I was playing.

*Alas, not enough guitar signal come through the line out to record at a reasonable level. Bummer, because you CAN use the app with line level output in use.*

So the Spark Mini turned out to be a complete tease. Here I have a cool new amp, and I basically can’t record with it without constantly disconnecting and reconnecting via Bluetooth, or playing blind and normalizing recordings after the fact. With several other choices in my arsenal, the Mini quickly went into storage.

Can’t mix and match heads and cabinets

There’s another oddity of the Spark Mini that I find limiting–you can’t mix heads and cabinets as with most modeling amps. They’re paired as Positive Grid sees fit–largely, it would seem, for historical accuracy. Then again, it might have something to do with the way the company models sound. I don’t know.

Regardless, as far as I’m concerned, every amp head sounds better paired with a Marshal 4×12-inch cabinet. I own a 1969 vintage 1960. I won’t sell it. They’ll bury me in it if I have anything to say about it. (I won’t because I’ll be dead)

I’m all for accurate portrayal of classic rigs, but I’m also, as just stated, all for being able to use a 4×12 cabinet to add meat and round out the deal.

So-so app, in-app purchases

I’m not in love with the Spark app. I didn’t find it overly intuitive, but my biggest issue is that the small skeuomorphic controls aren’t particularly easy to read, or zero in on with your finger tip. I much prefer the Marshall app that accompanied my CODE.

Then there are the ads for in-app upgrades. Jimi Hendrix amps are featured at the moment. I understand companies need to make money; but after someone just paid $200 ($230 when it finally ships) for a practice amp, I’m not sure charging another $20 for some of the most desirable models isn’t just a bit tacky. To be perfectly frank, I mentally unspooled my middle finger when I saw the ad pop up.

On the other hand, I like the fact that the app has a metronome for practice as well as songs, videos, and other instructional aids. I don’t need them, but the perqs are there for newbies. I wish I’d had them when I first started.

Me? I’d much rather just be able to connect via USB and Bluetooth at the same time! Priorities.

Great for practice, good for listening, weak for recording

It’s now three months post-TechHive review and the Android app still doesn’t allow “tone control” with USB connected, and the guitar output via line level is still way too low. The latter may be a hardware issue that only swapping the unit will fix. At least according to what I’ve seen in the Positive Grid forums.

The company has also been singularly uncommunicative about my issues since my review posted (PR was very squeaky beforehand and during) and doesn’t seem to respond on the forums with any regularity.

I gave the Spark Mini a very good rating in TechHive as it was reviewed solely as a portable speaker with auxiliary functionality. I stick by it, but here I can be more granular in my assessment.

Bluetooth speaker: Four out of five stars ****. It has adequate volume, good clarity, and a ton of bass response, albeit little to no stereo separation.

Practice amp: Four stars **** (maybe part of a fifth). It sounds good (not great), it’s super portable, and runs off battery so you can use it anywhere. It’s handy as all get out in this role, though still sonically limited by its size.

Recording amp: Two stars out of five **. No mixing of amps and cabinets, plus low guitar signal output from the line level connection. No way to change the sound of presets when connected via USB under Android. I basically found it unusable. If you have iOS, you can probably double the stars (****) and rate it usable if rumors are true. If you have an iPhone and Spark Mini and find it workable or better… LMK.

Final words

The Spark Mini is uniquely portable, so if you’re looking for a pure practice amp that won’t weigh you down or tie you to the AC, have at it. But… I’m still waiting to hear if the new shipping hardware fixes the line level issue. If not, I’d go with the competition (Marshall CODE, Fender GTX 100, Boss Katana, etc.) for recording.