Carl Martin Ampster review

This valve-driven DI box from Carl Martin could be the missing link for pedalboard users

Carl Martin Ampster
(Image: © Future / Phil Barker)

Guitar World Verdict

The Ampster adds valve warmth and balanced DI connectivity to any pedalboard, and has all the functions you need to dial in a great sound.


  • +

    Tone-sweetening and practical.

  • +

    A quality DI with ground lift.

  • +

    Series effects loop.


  • -

    Niche product but indispensable for ’board users.

  • -

    Needs a solid 1A of DC power.

You can trust Guitar World Our expert reviewers spend hours testing and comparing guitar products so you can choose the best for you. Find out more about how we test.

Based in Denmark, analog specialist East Sound Research has been turning out clever products for guitar and bass under the Carl Martin brand for nearly 30 years, and has an enviable artist roster that includes Joe Bonamassa, Pete Thorn and Kid Andersen. 

Adding to an already diverse range that includes pedals, amps and switching solutions, the Ampster is a valve-based DI box that’s poised to be popular for anyone who uses pedals.

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Nick Guppy

Nick Guppy has been a regular contributor to Guitarist magazine for over 20 years, mostly writing reviews on guitar amps and related products. He built his first valve amplifier at the age of 12 and has since bought, sold and restored many more, with a particular interest in Vox, Selmer, Orange and tweed-era Fenders, alongside Riveras and Mark Series Boogies. When wielding a guitar instead of soldering iron, he’s enjoyed a diverse musical career playing all over the UK, including occasional stints with theatre groups, orchestras and big bands as well as power trios and tributes. His favourite musical genres are ‘anything that’s good’.