Real owners rate these about evenly: 54% of 201 Marshall CODE 50 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, the CODE 50 and the Spark 40 land as affordable amps with a huge range of app-driven tones that owners still describe as thin and digital next to a real tube amp. CODE 50 players value its gig-capable volume and its once-dialed sound, but flag a cheap stock speaker many end up swapping, muddy factory presets, and a fiddly learning curve. Spark 40 owners call it a fantastic-value bedroom amp that is simple to use and fun for learning songs, while faulting reliability quirks like hiss or cutouts and noting it isn't loud enough to gig. A guitarist who needs one amp that can keep up with a band leans to the CODE 50; someone practicing at home who prizes ease and value leans to the Spark 40. It hinges on whether stage volume or simple bedroom practice is the priority.
“you made that sound better in 1 minute than I had in 1 year!”— @alexmcgrath674 on YouTube
“I own this amp and I can tell you, it sounds much better than it does on this video.”— @CapeFearDrift on YouTube
“been trying to tweak this amp for two years and still can’t get a decent tone”— @extramediumplease5965 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, the CODE 50 and the Spark 40 land as affordable amps with a huge range of app-driven tones that owners still describe as thin and digital next to a real tube amp. CODE 50 players value its gig-capable volume and its once-dialed sound, but flag a cheap stock speaker many end up swapping, muddy factory presets, and a fiddly learning curve. Spark 40 owners call it a fantastic-value bedroom amp that is simple to use and fun for learning songs, while faulting reliability quirks like hiss or cutouts and noting it isn't loud enough to gig. A guitarist who needs one amp that can keep up with a band leans to the CODE 50; someone practicing at home who prizes ease and value leans to the Spark 40. It hinges on whether stage volume or simple bedroom practice is the priority.
Owners point the Marshall CODE 50 at beginners and bedroom players wanting many tones cheaply, and tinkerers willing to tweak presets and use the app.
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 Marshall CODE 50 is thin, digital tone lacking tube feel. For the Positive Grid Spark 40, it's reliability issues, hiss or cutout.