Review Part One : Positive Grid Spark 40

Hey folks. This is part one of my review of the Positive Grid Spark 40. I’m breaking it into two parts because I wanted in the first place to focus on the usefulness of the Spark 40 as a home/practice/bedroom amplifier for electric guitar, acoustic guitar and electric bass. Part two, when it comes, will focus on the app specific functions including ToneCloud, Smart Jam, and Auto Chords.

Introduction

Positive Grid has been producing small amplifiers under the Spark name for a while. Don’t get that confused with Snark tuners, not even close to each other. Positive Grid at time of writing offers three amplifiers. The smallest is the 5w Spark Go, the 10w Spark Mini and the 40w Spark 40. My review only covers the Spark 40.

All power notations reflect a Class D solid state amplifier that is lightweight and effective. As I have written before, watts are watts, but the loudness of s 40w solid state amp bears no resemblance to the loudness of a 40w tube amp. I don’t think that you could gig successfully with the Spark 40, but it won’t likely get you evicted either.

I chose the Spark 40 because while I can use an app, I like the simplicity of actual knobs that I can easily tweak without having to go to well laid out but very small interface on my phone. The power output, the speaker size and the presence of real controls is what convinced me to go with the Spark 40. It’s about the size of a decent sized lunchbox, slightly taller and not as wide as the Yamaha THR II 30 or the Boss Katana Air that offer similar power output but that also cost a lot more money.

A professional musician of my acquaintance told me that I would not like the Spark 40. I asked him about his experience with it and was advised that one of his friends had been sponsored by Positive Grid but didn’t like the amp. So for me, the assessment had no value, and as I do, I decided to do my own.

Purchasing

Positive Grid Spark amps are sold direct. You can find them on Amazon, often with special pricing or directly on Positive Grid’s site. I bought mine direct because I wanted the Pearl White tolex, as I have plenty of black tolex already around here, and the price direct was better than Amazon and included a padded transport bag at no additional charge. Delivery was two business days. If you choose to buy any Spark amplifier check Amazon and Positive Grid and use one of those internet coupon hunters. It will save you money.

App Required

The Positive Grid Spark 40 will work without using the Spark App, but to really get the benefit of this small amplifier, you must use the app. It is a simple install and having been around for a while, the user interface is quite good. I find it too small on my iPhone, but it is really good on the iPad and iPad Pro. Folks with better eyesight will probably find the phone just fine.

Specifications

The Spark 40 is a pretty flexible product. It weighs in at about 11.5 pounds and is about 14 inches long by 7 inches tall and 7 ½ inches deep. I bought mine in what they call Pearl White tolex but by default it comes in black. The controls are top mounted. There is a standard ¼” input for your instrument and ⅛” output for your headphones. There is a small on off switch and a music volume control. The main knobs are the Amp Type selector, Gain, Bass, Middle, Treble and Master Volume, followed by Modulation, Delay, Reverb and overall Output. There are four preset selector buttons as well as a button that doubles as a tuner on or tap temp function. On the back is the connector for power which is provided by the included power block that plugs into a standard AC outlet. The power block supports input voltage from 110v to 240v. There is a bi-driectional USB Type A port and a ⅛” input for an Auxiliary music source such as your Smartphone or other media player. There is also an LED for when you use the unit as a Bluetooth speaker.

Frequency response is quoted as 20Hz-20KHz but that means little as it includes no + or - qualifiers. It provides stereo output at up to 116dB at 1m using a 40 watt Class D amplifier into a pair 4” speakers in a standard bass reflex design cabinet. Given the small speaker size, I expect that there is some computational audio being done as it sounds decent, even when used with a bass guitar with active pickups. The total impedance is 4 ohms which implies a very efficient (read louder at lower power) system.

There are 30 amp simulations as it comes from the factory, and as of this writing you can purchase additional amp sims from Positive Grid for download. The device includes 40 different effects falling into the categories of Noise Gate, Compressor, OD/Distortion/Fuzz, Modulation, Delay and Reverb. The only expansion pack I see is the Jimi Hendrix option which adds a Wah, some more amps, a Vibe and four fuzzes. AS there is no expression pedal input, I am not sure how the Wah works and i have not at this time purchased the Hendrix pack.

In the box comes the unit, the power adapter, a USB cable, a Quick Start guide and a license for Presonus Studio One. Initially this was Studio One Prime, but when Fender bought Presonus they killed off Prime and I believe you may now get a promo code for Artist although that could change without notice. If you use Windows, Studio One is an excellent DAW. If you use a Mac, you already have GarageBand, although there is nothing wrong with Studio One.

You will be reminded to download the Spark App which is available for iOS and for Android from Apple iOS App Store or Google Play respectively.

Audio Samples

I plugged the Spark 40 directly into my Mac using the supplied USB cable. It is USB A on one end and USB B on the other. Given that it’s 2023, I would have preferred it to have a USB C port on the amp just to reduce the number of different cable types that clutter up the studio space. I used Logic Pro for the recordings and as I often find, the input levels from the USB feed are very low. Consequently I had to use a neutral boost in a flat EQ to get the levels up to useful. The downloadable docuemtation says that the music volume knob that controls the output from the Aux in controls the USB level, but if it does, it sure doesn’t do anything for the USB level out from the amplifier itself. I found manipulation of the Master Volume in the virtual amps helped a bit depending on the amp.

The first sample is a Strat in position 4 going into the Spark implementation of a Matchless DC 40. I am guessing at the real amp of course, because most amp sims do not name the actual amplifier but use other names to suggest what it is. The controls are like a DC 40 so that’s my guess. The amp was set completely neutral with no effects on in the Spark and nothing applied in post except the aforementioned boost. It sounds to me pretty good through the amp speakers and better through the studio monitors during playback.

The second sample is the same Strat in the middle position, same amp, but with an LA comp, an SAB drive, an Echo and a short plate reverb. The echo virtual stomp looks like an Echoplex and while decent, doesn’t really achieve the real sound of tape delay. That said, it’s a rare digital pedal that does.

The third sample is a Martin SC-13e plugged into the Spark and uses the Pure Acoustic virtual amplifier. The sample also has an optical comp applied as well as Studio B reverb. It sounds decent enough, but as I left the amp sim completely neutral, I think that it could be improved with some tweaking and some work in post production because the source is a piezo pickup, and sadly, sounds like a piezo pickup. I did try different acoustic amp options in the Spark app, and this was the best sounding option. I would have to do a lot more playing around before I could say that the amp is a good choice for a piezo equipped acoustic.

The fourth sample is a Les Paul Axcess bridge pickup into the Spark Plexiglas amp sim with a Hall Reverb. It is pretty Plexi-ish and the amp does a decent job through its native small speakers. Electric players will be very happy and there are a lot of other “driven” amp options to choose from, I just like the sound of a Marshall Plexi.

The fifth sample is the same guitar, neck pickup with a Big Muff added in the Spark effects chain. I think it does a terrific job recorded and live. To me, it sounded better than a real Big Muff.

The final sample is a Jack Casady bass, which when first released was sold as a Les Paul bass back in the seventies. It is semi-hollow and has a single pickup with a three way tone cap setting. For this effort, the tone cap was set to 250. If you’ve never seen one of these basses, Gibson did a guitar and a bass in the early seventies as gold tops only. They did not sell particularly well and if you find one today, on most of the examples that I have seen, the gold top has discoloured to an ugly mold green. Epiphone does the Jack Casady signature now and it is an excellent bass with a lot of soul because of its semi-hollow construction. I used the Spark RB800 bass amplifier which looks Ampeg-ish. No other effects in the chain and I think it sounds great. This confirmed for me that the Spark 40 is a really good bass amp as well.

Conclusions

From a price perspective and if battery power is not a concern, it is my opinion that the Spark 40 is a great selection in a space that includes the excellent Yamaha THR and Boss Katana AIR products. It is much more than a simpler small bedroom amp like the Blackstar Fly Rig 3, and while Yamaha includes its excellent Line 6 effects and Boss includes their own effects, in my opinion the effects in the Spark 40 are quite decent. As is typical, you have to so some guesswork to figure out which amp sim is supposed to be what amp, and the same is true for the virtual effects pedals. In its use case as a small portable bedroom / practice amp that can also be used as a USB interface for recording yourself, I think that the Spark 40 is a winner. In reviewing those who do not like it, with respect, I find that they complain that it does not do what it’s built to do. For example, I think that the delays are ok, but not great, but then consider that the entire package costs less than a high end delay pedal on its own, so the reviewer who complains that the delays are not as good as their Strymon El Capistan may be coming from a place of unrealistic expectations.

I am not pleased with the manual. It’s pretty lightweight and can be confusing or wrong. For example it states that the DAW level over USB is controlled by the Music Volume knob, whereas I found that it did nothing at all. Mind you, I only use Macintosh computers so that may be a Windows thing as Windows requires a separate ASIO driver.

There is a lot of stuff NOT covered in this review because I do not write about that which I do not know and have not used. As I dive into the additional functions and build competence in using them, a part two will come out.

As always, thank you for reading. Please submit comments and questions. Until next time, peace.