Positive Grid has a new ultra-portable version of its high-tech Spark guitar amplifier. Designed for musicians seeking a versatile and powerful practice amp, the 3.5-inch-tall Spark Go works with a companion app loaded with virtual amps, pedals and other effects -- and it can even flesh out your sound with AI-powered drums and other backing instruments. Like its predecessors, the Spark Go pairs with an iOS / Android app to go far beyond amplifying your strumming and picking; it enhances it digitally. It includes 50,000 tones (ranging from boutique to modern), 33 amps and 43 effects and pedals, giving you plenty of novel ways to shape your sound. And if you want to learn new tunes, the app can sync with Spotify or Apple Music to display AI-generated chords for the song you're hearing. Engadget's 2021 review of the Spark Pearl (a larger model in the same line) found the app to have some rough edges -- including a less-than-convincing AI drummer.