Product Review: Positive Grid Spark Mini

Silly me, I thought the Positive Grid Spark Mini was a fairly new product, but my resident guitar repair guru and guy-who-will-try-to-fix-anything about town, Brian Stewart (Tree Strings Music), has already repaired one in his Red Wing shop. I haven’t yet heard what the fault was in that unit. I ordered a white one from Amazon, thinking it might be a fun practice and outdoor jamming amp. I’ve had it about a week and, sadly, the fun is wearing off fast. The good and bad news is that almost everything about this amp is driven by a phone/tablet app, iPhone or Android. The good is that it has hidden power if you’re willing to climb the usual steep software learning curve. The bad is, like most apps, it’s glitchy, unpredictable and often counter-intuitive, almost completely inflexible, and very dumbed-down while pretending to be a product for the sophisticated, discriminating guitarist (the ultimate oxymoron?). A lot of the positive reviews you will find for this amp begin with something like “I’m new to guitar and have only been playing about a few months . . .” It’s easy to like or even love something if you don’t have anything to compare it to. In my case, it’s hard for me to look at any product with the eyes of a newbie. So prepare to be disappointed if you’re hoping for that kind of bubbly, happy-talk review. At 74 and after 50 years in various areas of pro audio and music, there is nothing new about me except for the crap that keeps popping up every time I have a doctor’s appointment. Having spent 20-some years in test and reliability engineering I tend to find more things wrong with software than right.

 

You can’t beat the Mini’s physical controls for simplicity. On the top of the amp chassis, you get 4-position Preset switch (Rhythm, Lead, Solo, and Custom), a Guitar volume, a Music volume control (Bluetooth or Aux In signals), and a guitar input. The back of the chassis has 3.175mm (aka 1/8”) Line Out and Aux Input jacks, a USB-C port for charging the battery and (sometime in the future) a functioning digital audio interface), a Bluetooth “Pair” switch (the Pair switch also fires up a rudimentary guitar tuner), and a power switch. The amp comes with a cute leatherette strap and a pair of buttons to attach the strap on the side. The amp is a 10W Class-D unit that, supposedly produces 90dBSPL at 1m. The cabinet has two 2” speakers and a bottom-facing passive radiator. The 3Ah battery supposedly provides power for 8 hours (on mid-to-low power output) and charges from empty to full in 3 hours. The firmware contains “33 Amp Models, 43 Effects, (Noise Gate, Compressor, Distortion, Modulation/EQ, Delay, Reverb – fixed in that order) and the USB interface is a 44kHz/16 bit A/D. You also get a a free download of PreSonus Studio One Prime recording software with your original purchase. Registering for your software is the closest thing to registering for warranty with Positive Grid. You can buy (for $110) a Spark Control footswitch to either control the presets, turn on and off various virtual pedals, or a combination of those functions. The amp is 146.5 x 123 x 165 mm (5.76 x 4.84 x 6.49 in) and weighs 1.5 kg (3.3 lb).

As usual, the included paper “Quick Start Guide” is close to useless. Not so typically, Positive Grid hasn’t provided much in the way of useful information on their website, YouTube, or anywhere else. Figuring out the app and the various features of the amp that are only accessed through the app is up to the buyer.

For a beginning guitarist who doesn’t know any other musicians, some of the Mini’s app features are probably fun-to-useful. This “screenshot” is really a compilation of three different screens as typically displayed on a phone. The middle one is an example of a dumbed-down imitation of a fairly common DAW guitar pedal screen; like the one in Logic Pro. A big difference between the DAW pedal boards and the Spark is that you can’t reshuffle the order of the pedals to suit your purposes.

After spending considerable time playing with the various pedals I can say “they work.” The compressors in the Comp/Wah section aren’t up to DAW standards, but they are probably as good as most hardware pedals. The “Wah” function, also included in this group, is “Temporarily Disabled.” As usual, I don’t like the distortion (Drive) pedals much, but I rarely do. About half of the Drive pedals are red-flagged, which means you’ll have to spend $20 or more to enable those pedals on your device. So it goes for the Amp models, too. Most of the red-flagged amp models are variations on the mediocre Marshall models. The Mod/EQ models are predictable and not bad. The Delays are ok, except for the absence of a multi-tap delay. The Reverbs are typically pretty good, since digital reverb plug-ins have been fairly well staked-out territory for at least 20 years. I didn’t find a favorite from the verbs, but I didn’t find anything I hated either.

Irritatingly, with my Samsung tablet and the Samsung Music player, anytime I open the Spark app the music player starts playing something from my current playlist through the Spark Mini. Before you start babbling about some “play on Bluetooth connection” toggle in the player, get a grip on yourself. No other Bluetooth device that I own has this behavior: from consumer buds to Shure in-ears to three different Bluetooth speaker systems. It is a glitch in the Spark app and that has been logged by Positive Grid’s customer service and I wasn’t the first to make the complaint. If everything else was excellent this wouldn’t be a deal-breaker, just unpredictably irritating. (If it does this when I first open up the app, will it spontaneously do the same during a gig?) Yes, I could turn off the Music volume, but if I am using it as a backing track at the time it sort of defeats the purpose of that function.

With that out of the way, my impression of the guitar amp is somewhat positive. I’m not fond of electric guitar distortion in the usual buzz-box fashion, but some of the amp models deliver decent slightly over-driven sounds with the kind of amp EQ and tone you’d expect from what I’m guessing are the amps being modeled. Some of the setups both by other users and Positive Grid are fair-to-decent. I had some high hopes for Pat Metheny style sounds, but the lack of multi-tap delays squashed that. You could just add a pedal delay up front but that would defeat my purpose. I have an old MacBook Pro with MainStage that will do everything this unit does with a ton more effects including my multi-tap delay that I’d rather use with a small wired power speaker than add a pedal that is almost as big as this amp.

And speaking of power, I wouldn’t be surprised if the Mini an produce 10W, but the distortion at that output would be objectionable. That goes for the spec’d 90dBSPL@1m acoustic output, too. At any volume over a moderately loud voice or a strummed full-size acoustic guitar, the bottom end of this amp clips indecently. It is not a pleasant distortion, either. It is the usual splatting sound of digital clipping. That was the straw that broke the back of my interest in the Positive Grid Spark Mini. There were moments when I thought I was about to find the sweet spot for several of the Presets but “almost there” was as close as I got to something useful. When the amp sounded good, it was too quiet to compete with a couple of acoustic guitars. When it was loud enough to cut through a small instrument crowd, it sounded awful.

For a beginning practice amp the Spark Mini isn’t bad. Most beginners, however, will have a terrible time with the mediocre application software that is an absolute necessity for using the amp. Advanced users will be frustrated with the user-hostile programming of the app and disappointed with the little amp’s small performance.

Acoustic Guitar String Comparison

This all started when someone from Cleartone Strings sent me a note on my Wirebender Audio Facebook page asking if I’d be interested in reviewing sets of their acoustic and electric guitar strings. I’m up for free stuff, so I said “sure” and they sent me two pairs of their Custom Light 11-52 Acoustic Phosphor Bronze Treated Strings. These are not cheap strings at $17.99 a set, but I have been playing D’Addario 11-52 Custom Light Phosphor Bronze Coated Acoustic Guitar Strings for the last couple of years after almost 20 years of almost exclusively playing Elixir Nanoweb Phosphor Bronze Lights and Custom Lights and those strings are all in the same price ballpark. All of these strings make similar claims to longevity, also, with a special coating and other process secrets.

I have two Composite Acoustics guitars, the OX and a Cargo. I’ve been waffling on how I feel about the D’Addarios on the Cargo since I started using them, but I’ve been really happy with the OX’s tone with those strings. Mostly due to the added “edge” the brighter D’Addarios add to the larger bodied guitar, which isn’t an “effect” the Cargo needs.

Before I replaced my current set of D’Addario’s, I examined the strings and, especially, the coating and listened carefully to the sound and measured the output on my Composite Acoustics OX with both the pickup and a Shure KSM 141 microphone. I’m going to make a wild claim here that the CA OX, being a carbon fiber guitar will do a good job of neutrally demonstrating whatever character there might be to guitar strings. I could be wrong, so sue me.

The D’Addarios sound clean, relatively bright, and have enough bottom to make the guitar as full as a guitar this size should sound. They were recommended by my local guitar expert, Brian Stewart, Tree Strings Music, and they have been everything he said they would be, including long-lasting and a moderately different sound from my Elixirs. The Elixirs are more mellow, maybe slightly more full than the D’Addarios and that impression is true across the six strings. I have liked these strings for more than 20 years, especially during the years when I rarely played my guitars. Before using the Elixirs, my strings would often be ruined before I had an hour of playing time because of corrosion from being exposed to either the local humidity or the humidifier in my guitar case.

The ClearTone strings were a fail right out of the package. The first thing I noticed about the ClearTone strings was for the first time in the 6 years I’ve owned my CA OX the low E string buzzes like crazy. With the same gauge D’Addarios, the guitar rang clear and clean on all strings. It is only the low E that is rattling and I have no idea what that means, although the whole set feels lighter than the D’Addarios I’d just removed. [Obi-Wan-Brian Kenobi-Stewart suspects the ClearTones might be round-core, rather than hex-core strings. I guess round-core is a trendy “vintage” design, but it’s also know for being fragile, likely to come apart of the strings aren’t crimped near the tuner post, and to have problems like those I’m experiencing.] It’s nice that the guitar is more easily played, but at the cost of “clear tone” (pun intended) from all strings? Probably not so nice.

I was about to yank the ClearTone strings when I thought I saw a section of the wrap pulled apart. When I looked closely, the source of the rattling problem was obvious. The wrap (whatever that is called) at the ball-end of the string is so long (only on the A and low E strings) that it extends slightly past the edge of the saddle. You can sort of see it on the attached picture (at right). That explains why it rattles everywhere, because it is rattling at the freakin’ saddle! If I put a little bit of fingernail pressure behind the saddle, it rings clear. It’s a manufacturing/design problem and a weird one because every other string has shorter wraps, but none of them is consistent in length.

Outside of the design problem, the ClearTones are somewhat less bright than the D’Addarios and seem even a little more dull than the Elixers but with considerably less fullness of tone. In fact, I think the ClearTone strings make my guitar sound like it is made out of plastic (which it kind of is). I left them on for a disappointing week and discarded them to return to the D’Addarios. I was disappointed enough with the first experiment that I did not bother to try them on the CA Cargo.

Initially, I’d planned on doing a lot of data collection for this review: charts and graphs, screen shots of string amplitude and harmonic content, and maybe even some sustain tests. Honestly, I don’t think any of that would be useful information after what I have experienced with the ClearTone acoustic strings. Your experience may vary, but I’m just not happy enough with the initial experience with these strings to put much more time into them. 

I suspect my career as an “influencer” will be short. It’s pretty obvious that advertisers imagine that they are paying for a good review, not an honest one. Magazines have been threatened with and lost advertising revenue when a mediocre product is identified as such. All of my revenue from my blogs comes from the occasional hit my readers make to the advertisements in the blog. I have very little control of the ads (I can only tell Google and Wordpress not to use an ad I find objectionable.) and I kind of like it that way.

“You Can’t Hear What I’m Hearing”

This scene in the movie “Crazy Heart” is probably my favorite music business scene in any movie ever, including documentaries. Bear, the deaf-and-dumb front-of-house goober, tries to tell Jeff Bridges’ character, Bad, that he can’t believe his lyin’ ears and should trust someone who probably never critically or competently listened to a record in his life. “The mix is good man. You can’t hear what I’m hearin’ out here.”

Instead, Bad does what every musician should do in a live performance; he stops the rehearsal until the goober does what he tells him to do. “Yeah, you’d be surprised. Set it the way I tell you and leave it!” After a short, hilarious wrestling match between the goober and Bad, the show goes on. Of course an even better solution would be to have a bodyguard/assistant standing behind the FOH nitwit smacking him every time he touches a fader. It doesn’t matter how much the assistant knows about music, it will always be more than the FOH goober.

The power of the mix should be on the stage, but usually it isn’t because the musicians are so swollen up with their ego crap they don’t bother to listen to what the audience is suffering through. They smother themselves in a wash of stage monitor noise that buries the FOH sound and allows the worst people on the planet to torture their fans with incompetence. Worse, most musicians are convinced that being loud will cover up flaws, which is beyond stupid.

There are at least two ways (both negative) to take Bear’s reply, though:

1. “You can’t hear what I’m hearin’ out here” could be a reflection of Bear’s deafness: “I’m mixing to compensate for decades of severe hearing loss and general stupidity and you’ll never know what I’m hearing.”
2. Or Bear is pretending the FOH position is important enough to tell Bad “you can’t hear” what he’s doing because what Bear isn’t going to allow it. The goober thinks Bad’s opinion doesn’t matter. In other words, you don’t have permission to “hear what I‘m hearin’ out here.”