“Modified connects us with a long-standing tradition of modifying Marshall amps that dates back to the 1970s”: Marshall unveils factory modded takes on the 1959 Plexi and JCM800 – tipping its cap to the amp wizards of rock’s golden era

NAMM 2025: Marshall has announced the arrival of its first commercially available factory-modded tube amps, the 1959 Modified and JCM800 Modified.

We knew some form of modified amp was on the way. Guitar World first broke the news last year in an interview with Marshall Group CEO Jeremy de Maillard, in which he told this writer that the legacy amp giant had big plans for new products and revealed “mods came very early into that conversation.”

At the time, after being sworn to secrecy, I was also given a tantalizing glance at an early Modified unit but was not able to hear it in action at the time. Since that point Ryan ‘Fluff’ Bruce posted a teaser image of a 1959 Modified over on Instagram, noting “NAMM is gonna be fun.”

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Now we have the official announcement and it seems both the 1959 (AKA the Plexi) and the JCM800 are getting the factory mod treatment.

“Modified connects us with a long-standing tradition of modifying Marshall amps that dates back to the 1970s,” says the firm.

“Artists, both in studios and on stages, were looking to get something different from the industry-standard amps of the time. Marshall mods were sometimes about getting ‘more’ – more distortion, more sustain, a bigger sound.

“Other times, they were about versatility, allowing musicians to achieve sweeter tones or to get the best from their Marshall heads without driving them to ear-splitting volume levels.”

As such, the 1959 Modified combines a host of popular mod options into one unit, including the popular Master Volume tweak (which enables players to get a gained-up crunch at lower volumes), a switchable bright cap (for fine-tuning the highs), a gain boost switch, plus a clip type switch, enabling a choice of diode or transistor clipping.

The JCM800, meanwhile, adds a gain boost switch favored by ’80s classic rockers, alongside a mid-boost (helpful if you want solos to cut through the mix), and a tight switch, which cuts the low-frequency flab for modern, down-tuned metal playing.

It’s a smart move from the firm: tipping its cap to the popular Marshall mod scene and the much-admired work of the so-called amp wizards of the ’70s and ’80s, but doing so from its original home in the UK.

The mods are all completed to order in the firm’s UK facility at Bletchley and, perhaps unsurprisingly, carry a price to match that prestige, with the 1959 Modified coming in at $3,699 and the JCM800 costing $3,299.

The Modified series isn’t the only new announcement from Marshall at this year’s show, the firm’s also unveiled a line of Marshall Overdrive amp-in-a-box pedals, bringing authorized takes on Plexi, DSL and JCM amp tones to your pedalboard for the first time.

For more information, head to Marshall.