Hands-On Review:DigiTech RP55, RP155, RP255, and RP355 Multi-Effects Processors

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The RP family expands with more firepower and more control

By Ara Ajizian
Musician’s Friend Staff Writer

Since their introduction in 2006, DigiTech's RP Series multi-effects processors have established themselves as leaders in the field with realistic models of amps, cabinets, and effects; intuitive programmability; and realtime control. At this year's Winter NAMM show, DigiTech unveiled a number of new RP units, completely revamping the line. Not long ago I reviewed the reigning king of the series, the RP1000, which incorporates an advanced switching system and really is a beast unto itself. For this review, I evaluated its newest siblings—the RP55, RP155, RP255, and RP355.

A quest for tone

Every musician has to start somewhere. Typically, it's with a less expensive guitar and amplifier setup. I know in my own experience, finding my sound didn't come until I had spent many hours honing my technique. After all, what's the point of playing through a $1,500 tube amp if you really can't play that well? With the inexpensive, fully functional RP55, it's easy to work on your chops and explore different tones at the same time.

With its small footprint and simple, intuitive controls, it's perfect for bedroom practice, and for those who have yet to settle on their first real amp or effects setup. With its 11 amp, 5 cabinet, and 20 effects models, you can easily experiment with different setups to find your sound. Among its 11 amp models are vintage tube favorites as well as modern, high-gain staples. Combine any of them with the five different cabinets and get the feel for what a 2x12" combo sounds like compared to a 4x12" half stack. With its AudioDNA DSP chip, the RP55's models give you a great reference point when it comes time to buy your first amp or upgrade from a practice amp.

On the effects front, it's loaded with 20 studio-quality models based on DigiTech favorites like their flanger, chorus, phaser, tremolo, three different delays, and six reverbs. Plug in an expression pedal and take full advantage of the Dunlop Crybaby model, or get your Tom Morello on with the DigiTech Whammy. With the ability to run eight effects at once, it's easy to dial up tons of great tones, no matter what style of music you're into playing.

Another fantastic feature of the RP55, especially considering its sub-$50 price point, is the built-in drum machine. We've all known players who spend countless hours practicing in their room, only to find it awkward when it comes time to play with other musicians—particularly drummers. Jamming along with the RP55's numerous beats will make your practices much more productive.

The DigiTech RP Family of Multi-Effects Processors

Sibling rivalry

The three bigger brothers to the RP55—the RP155, RP255, and RP355—share a number of features but get more robust in different ways as you move up the line. All three make use of DigiTech's 24-bit AudioDNA2 DSP processor for state-of-the-art, incredibly accurate modeling of amps, cabs, and effects. USB connectivity allows you to easily record to your DAW software (or the included Cubase LE4), as well as edit patches using the free, downloadable X-Edit software for your PC or Mac. X-Edit is a simple, intuitive alternative to programming and saving patches via the units themselves, particularly for visual types like me. Each unit also comes with 30 tone and 30 effects libraries for instantly calling up entire high-quality rigs with ease.

The RP155, RP255, and RP355 also include a 20-second looper, a powerful addition that can really expand your creativity when it comes to writing. I've always done my best songwriting in group situations as opposed to being alone, but found with the looper, drum machine, and USB connection I had plenty of tools at my disposal to turn the ideas in my head into concrete, fleshed-out tunes that I could present to the band.

Different strokes

One difference among the RP155, RP255, and RP355 is in the number of models each contains (see Features & Specs). Additionally, the RP255 and RP355 incorporate an expression pedal for controlling not just effects, but virtually any parameter you choose. Both also provide an 1/8" stereo input for connecting an external device to play along with. This is great if you're trying to learn a particular song or part and need a convenient way to hear it as you jam.

The RP355 has some extras that make it even more powerful for both recording and live performances. Balanced XLR line outs ensure you're ready for any situation a sound man can throw at you, while the Stompbox Footswitch mode gives you the convenience of turning distortion, chorus, and delay effects on or off with the tap of your toe, just as you would with a stompbox. With the most I/O, models, and control of all the new RP units, the RP355 is clearly the choice for the gigging, pro-level guitarist who needs an easily accessible universe of tone.

Keep it in the family

DigiTech's commitment to players of all skill levels is evident in these new RP units. Whether you're just starting out and need access to powerful practice tools and high-quality tones, are an intermediate player looking to find new sounds and hone your songwriting skills, or are making a living on the club circuit, there's an RP for you. Thanks to features like a built-in drum machine; AudioDNA or AudioDNA2 DSP processing; and of course the myriad amp, cabinet, and effects models that each possesses, the RP Series has the power you need to take your music higher.

Features & Specs


  • 11 amp, 5 cab, 20 effects models
  • 8 simultaneous effects
  • AudioDNA DSP processor
  • Drum machine with 30 patterns
  • 40 user/40 factory presets
  • Built-in tuner
  • Expression pedal input
  • 24-bit analog-digital converters


  • 83 amp, cab, and effects models
  • Lexicon reverbs
  • 11 simultaneous effects
  • AudioDNA2 DSP processor
  • 20-second looper
  • 24-bit/44.1kHz sample rate
  • 2x2 USB 2.0 audio streaming
  • Drum machine with 60 patterns
  • 30 tone/30 effects libraries
  • 50 factory/50 user presets
  • Independent 1/4" stereo outputs
  • Amp/mixer switch for optimizing outputs
  • USB editing with DigiTech X-Edit software
  • Power supply included


  • Same features as the RP155 with 94 amp, cab, and effects models; 60 factory/60 user presets, and onboard expression pedal.


  • Same as the RP255 with 3 selector pedals and 126 amp, cab, and effects models; balanced XLR line outs, and Stompbox Footswitch mode.