Geary Yelton reviews the AdrenaLinn II, the updated version of Roger Linn Design''s award-winning effects processor for guitarists.

Although Roger Linn has had a measure of success as a guitarist and songwriter, he is best known for designing the first digital drum machine (the Linn LM-1) as well as Akai's popular MPC series of sequencer workstations. In recent years, he has turned his attention to creating new effects processors for guitarists, a path that led to developing the AdrenaLinn, winner of a 2003 EM Editors' Choice award (for more info, see the August 2002 and January 2003 issues, available online at

Like the first AdrenaLinn, the new model hosts dozens of effects in a stompbox the size of a paperback novel (see Fig. 1). In addition to offering basic drum-machine functionality, it is a sequencer-driven dynamic filter, distortion processor, amp modeler, delay line, noise gate, and more. You can load one effects Preset and one drum pattern at a time and switch them by turning a knob, pressing a footswitch, or sending a MIDI command.

In many ways, the AdrenaLinn II is identical to its predecessor, but it has numerous enhancements, including simplified effects programming, three times the maximum delay time, twice as many amp models, and revised drum sounds and patterns. Owners of the older model can order a kit ($99) to upgrade their AdrenaLinns to the newer version.


The shell of the AdrenaLinn II is a black cast-aluminum box with a vinyl overlay that's available in yellow or blue. Front-panel controls consist of two rugged footswitches, four detented infinite-rotation knobs, four tiny buttons, and a trim pot for adjusting the input level. A red Clip LED and 16 green indicator LEDs supplement the main display, a large 3-character LED. The construction is reasonably robust, and the unit should easily withstand anything short of outright abuse.

The back panel provides a ¼-inch mono input for your guitar, two ¼-inch outputs, MIDI In and Out ports, and a connector for the included 9 VDC wall wart (see Fig. 2). A ¼-inch stereo headphone jack is a welcome addition that was missing from the earliest models of the AdrenaLinn. All the connections are labeled on the top of the front panel, making them easy to identify from overhead. I am disappointed that the unit has no power switch. I also wish that the device could be battery-powered for increased portability.

One especially thoughtful touch is that the AdrenaLinn II has two output settings: one for a flat-response sound system and another for a guitar amp. The Amp setting compensates for the boost in upper midrange frequencies that a guitar amp typically produces; it affects the sound of only the amplifier models.

On the front panel is a printed matrix from which you can select rows of functions for each of the four knobs. By default, turning the knobs selects Presets, Drumbeats, Tempo, and Volume, and the alphanumeric LED displays the selected value. Holding the Main button for half a second selects four secondary functions, and tapping on the button returns to the main functions. For additional functions such as editing Presets, arrow keys step through eight rows of four parameters printed on the front panel: two rows for effects, two for amp models, one for delay, two for Drumbeats, and one for MIDI. By pressing the up and down buttons at the same time, you can also access hidden parameters such as alternate modulation sources and filter modes.

Because the main display shows only three characters, most words must be abbreviated. A legend printed on the front panel shows the 3-letter names for the 14 effects types and 6 amp models. Because more amp models are available, though, and because parameter names are also abbreviated, you might want to keep the user manual handy.


The AdrenaLinn II provides a remarkable variety of effects that includes virtually everything except harmonization and reverb (which are probably better left to more expensive or dedicated devices anyway). Although its specialty is filter effects, the AdrenaLinn II is also capable of rotary-speaker simulation, vibrato, tremolo, autopan, flanging, chorus, and even arpeggiation. Each effect offers a handful of variations; for example, tremolo can be a slow stereo pan, a hard switch between left and right, a slow pan to the left followed by a hard pan to the right (called sawtooth tremolo), or a randomly selected pan position for each tremolo pulse.

A Preset combines one effect, an amp model, and a delay. You can set up the Bypass switch to determine the combination that goes into effect when you press it: effect only, effect with delay, and so on. Time-based effects can always be synced to tempo, which is determined by the current Drumbeat or by an external MIDI Clock. A single cycle of a flanger, for example, can be a quarter note, one bar, or four bars long. Random Filter is a Preset that selects a new cutoff frequency every eighth or 16th note.

Some effects are variations on their classic counterparts. Most filter effects use an envelope generator triggered by an audio signal to control the filter's cutoff frequency, which produces an auto-wah type of effect first popularized in the late '70s by a stompbox called the Mu-Tron (see Web Clip 1). Talk Box is a simulation that doesn't require you to put a plastic tube in your mouth. It's really just another autofilter effect, but it sounds as though it could occasionally substitute for the real thing (see Web Clip 2). Rotary Speaker has two speeds, but the shift between them is abrupt, unlike the shift on a real Leslie.

The AdrenaLinn II offers several Presets that use Filter, Tremolo, or Arpeggio Sequences. The factory settings provide 20 sequences of each type, and if you have the patience, you can program a different sequence for each of the 100 User Presets. Each sequence is 32 steps long. For each step, you can determine the Level and whether a two-stage envelope generator is on or off. The Level parameter controls cutoff for Filter Sequences, volume for Tremolo Sequences, or pitch for Arpeggiator Sequences. Because Arpeggiator Sequences always play the same note pattern no matter what you play (see Web Clip 3), I found the Filter Sequences to be much more versatile (see Web Clip 4). You can, however, modulate Arpeggiator Sequences with a MIDI keyboard or other controller.

Several of the effects offer MIDI-controllable parameters. You can control envelope rates with Velocity, for example, or control filter frequency with Aftertouch or one of several other MIDI CCs. You can also assign MIDI CCs to modulate flanger frequency.

The delay section provides a single-tap delay, which doesn't sound especially exciting at first glance. However, you can specify delay times that relate to tempo in a variety of lengths: one every two measures, three every four measures, one every measure and a half, and other variations. The maximum delay time is an impressive 2.8 seconds, long enough to record and play loops in real time (see Web Clip 5). Even at the highest settings, though, it can't produce an infinite repeat.


Even if you use such effects rarely, you'll probably make frequent use of the AdrenaLinn II's guitar-amplifier modeling. You can select from 24 amp models ranging from simulations of genuine classics to simple fuzz and clean console EQ, and they all sound quite good. Real amp simulations include four Fenders, three Marshalls, a Hiwatt DR103, a Budda Twinmaster, a Roland JC-120, a Soldano SLO-100, two Mesa/Boogies, and two Voxes. Five additional settings are Roger Linn Design Thin, Blues, Deep, Bright, and Rectified.

For each amp, you can set the overdrive gain, 3-band EQ, and output volume. You can also specify whether the effects occur before or after the amp in the signal chain. All of the overdrives sound great, though not necessarily as warm as the distortion a real tube amp produces.


The Drumbeat section plays four-voice patterns using individually sampled hits, but it lacks some of the capabilities of a full-function drum machine. Pattern length is always two measures, and you can't chain patterns together to sequence a song. Nor can you send MIDI Program Change messages to change Drumbeats without also changing the effects Preset. You can change them with MIDI Song Select messages, however, so you can chain patterns with the aid of an external sequencer.

Even without onboard pattern sequencing, the Drumbeat section makes the most of its resources. Like the original AdrenaLinn, the AdrenaLinn II has memory enough for 100 factory beats (F00 through F99) and 100 user-programmable beats (U00 through U99). Straight from the factory, the User Bank duplicates the Factory Bank to supply beats you can edit. Location 99 contains a metronome click, and 100 is silent. Styles range from straight rock to syncopated funk to swinging hip-hop to some pretty happening techno patterns (see Web Clip 6). A few make good use of the onboard processing, but most are dry. Each beat has its own tempo, but you can easily override that default. The collection offers enough variety that you should have no problem finding a groove that inspires you.

As you might expect from the man who invented the LinnDrum, the quality and selection of the drum samples is consistently good. Most are recordings of real drums, but synthesized sources such as the Roland TR-808 are available, too. Each Drumbeat contains 16th notes, eighth notes, or eighth-note triplets; the two measures are identical in most factory beats. Each step contains a bass drum, snare, hi-hat, and percussion voice. Each of the first three voices offers a choice of 9 samples, and the last gives a choice of 15 sounds. Whereas the bass drum is always a kick and the snare drum is always a snare, the hi-hat voice could be a different cymbal or a tambourine. A percussion sound might be a tom, a triangle, an electronic zap, or any sound that doesn't fit the other categories.


Guitarists have been reaching for new sounds since electric guitars first appeared, and effects processors have steadily evolved to meet their needs. The AdrenaLinn II is a significant step in the evolution of stompboxes. Considering the number of effects that are packed into this single stompbox, the AdrenaLinn II is a bargain in anyone's book. It does so many sounds that it might take you awhile to explore everything. Luckily, the user manual is quite good. Best of all, the AdrenaLinn II offers effects that you won't find anywhere else.

Associate editorGeary Yeltonused to play bass professionally, but now he's a veteran knob-twister. Still, his favorite instrument is a Gibson guitar that's even older than he is.

AdrenaLinn II Specifications

Analog Input(1) unbalanced ¼" TSAnalog Outputs(2) unbalanced ¼" TS; (1) ¼" stereo headphoneMIDI PortsIn, OutEffects Presets(100) factory, (100) userDrum-Pattern Presets(100) factory, (100) userEffect Types14Amp Models24A/D/A Conversion24-bit, 40 kHzInternal Processing32-bitDisplay3-character LEDPower9 VDC adapterDimensions7.5" (W) × 1.4" (H) × 4.7" (D)Weight2 lb.


Roger Linn Design

AdrenaLinn II
effects processor


PROS: Lots of unique effects. Real-time MIDI control. Outstanding value.

CONS: No power switch. No battery power. Can't display Preset or parameter names.


Roger Linn Design
tel. (510) 898-4878