Real owners lean toward the Boss Katana 50 Gen 3: 65% of 625 owners recommend it, vs 54% of 52 for the Positive Grid Spark 40.
Verdicts aggregated from Reddit, enthusiast forums, and YouTube owner comments — affiliate reviews excluded. Sample sizes differ; judge accordingly. How we score
Across both owner bases, value is the headline, the Katana 50 Gen 3 and Spark 40 are each called excellent for the money as practice amps with deep tone libraries. Katana owners point to great cleans and models, a big built-in effects stack that stands in for pedals, and a tube-like feel, tempered by stock tones that need dialing in, a fiddly editing interface, and a sound some find processed next to a tube amp. Spark 40 owners enjoy its huge app-driven tone variety and how fun it is for jamming and learning songs, but several hit reliability quirks like hiss or dropouts, note it isn't loud enough to gig, and say it leans thin and digital versus tube amps and needs the app for full benefit. A player who wants variable wattage and an amp that scales past the bedroom leans Katana; a beginner focused purely on at-home practice with app-based features leans Spark 40. The decision hinges on whether you need headroom beyond home practice or just an easy, tone-rich practice companion.
“This amp is a no brainer. Cheap and delivering a great sound and loaded with features.”— @088Noir on YouTube
“Told my parents i wanted world peace for christams, but if i couldn't get that, Id want the amp instead lol”— @jakerobertson5198 on YouTube
“now it has a wool blanket thrown over it”— @ReductioAdAbsurdum on YouTube
“What I love most about Spark is when I want to learn a song, I search the cloud for the song.”— @jrigwald on YouTube
“The best practice amp I have ever owned. Full stop.”— @l-Libertine on YouTube
“The first built-in practise pattern I tried has got wrong chord positions in the grid - pretty much useless for a beginner, who *depends* on the practise material to be _correct._”— @Noone-of-your-Business on YouTube
Across both owner bases, value is the headline, the Katana 50 Gen 3 and Spark 40 are each called excellent for the money as practice amps with deep tone libraries. Katana owners point to great cleans and models, a big built-in effects stack that stands in for pedals, and a tube-like feel, tempered by stock tones that need dialing in, a fiddly editing interface, and a sound some find processed next to a tube amp. Spark 40 owners enjoy its huge app-driven tone variety and how fun it is for jamming and learning songs, but several hit reliability quirks like hiss or dropouts, note it isn't loud enough to gig, and say it leans thin and digital versus tube amps and needs the app for full benefit. A player who wants variable wattage and an amp that scales past the bedroom leans Katana; a beginner focused purely on at-home practice with app-based features leans Spark 40. The decision hinges on whether you need headroom beyond home practice or just an easy, tone-rich practice companion.
Owners point the Boss Katana 50 Gen 3 at budget players wanting the best value amp, and bedroom and jamming players at variable wattage.
Owners point the Positive Grid Spark 40 at bedroom and at-home practice players, and beginners learning songs and dialing in tones.
The most-cited downside of the Boss Katana 50 Gen 3 is default and out-of-box tones can underwhelm until dialed in. For the Positive Grid Spark 40, it's reliability issues, hiss or cutout.