The MXR Joshua Ambient Echo is a compact digital delay pedal from MXR, released in 2024, that aims to put the sound of 1980s rackmount stereo delay units into a standard MXR compact enclosure, the same size as a Phase 901. Its name is a nod to U2's 1987 album The Joshua Tree, whose guitar parts, played by The Edge, were built on rhythmic, ambient delay from studio rack processors1. MXR says it is tuned by Jeorge Tripps to deliver the soundscapes of vintage rack-style processing2.
It is not a signature pedal and The Edge does not use it; his delay sounds are the inspiration rather than an endorsement3. What you get is rhythmic delay with an optional second echo, modulation, octave voicing on the repeats, tap tempo, and a delay time range of 50 ms to 1000 ms2.
The Edge's Joshua Tree delays in a compact pedal
The pitch is straightforward: the rack delay units of the 1980s, the kind crucial to The Edge's trademark sounds on The Joshua Tree, recreated in a pedal that fits a normal pedalboard1. Guitar Pedal X's Stefan Karlsson described the circuit as a smart take on the TC 2290 rack unit, and called the pedal "a fantastic encapsulation of that sort of TC2290 sound in a truly smart form factor," while noting it is "a little clunky in some ways to operate with hidden features"5.
The enclosure is a white sparkle finish in the standard MXR compact size, with six knobs and two color-changing push-buttons on top15. Delicious Audio describes the aim as offering, in a compact case, the legendary sound of The Edge as heard on that 1987 album, a guitar sound drenched in rhythmic yet ambient delay7.
"MXR has done an incredible job here of giving you the Edge's Ambient Effects - as deployed on the 1987 Joshua Tree album."
The controls
Six knobs handle the main parameters: Delay, Mod, Voice, Regen, Division and Mix8. Two top push-buttons, Echo 2 and the bypass/tap footswitch, sit alongside them9.
| Control | What it does |
|---|---|
| Delay | Sets delay time, 50 ms to 1000 ms2 |
| Division | Cycles through rhythm settings: 1/4 note, dotted 1/8, 1/8, 1/8 triplet, double echo with an 1/8 note, and dotted 1/84 |
| Regen | Controls the delay's feedback7 |
| Mod | Adjusts modulation depth and rate together; secondary functions let you set them separately10 |
| Voice | Sets the amount of down and up octaves (-1, +1 and +2) on the repeats7 |
| Mix | Balances dry and delayed signal8 |
| Echo 2 switch | Adds a second echo that always comes in at a quarter note relative to your tapped tempo10 |
| Trails switch | Engages buffered bypass so repeats fade out when the pedal is switched off42 |
| CTR mode switch | Sets the CTR jack for expression, tap or stereo right output42 |
Tap tempo works by pressing and holding the footswitch for one second, then tapping your rhythm; the Echo 2 button flashes while you are tapping410. Holding down an off-board switch connected to the CTR jack freezes the echo lines at maximum feedback and blocks any new signal from entering the echo until you release it, a freeze mode for ambient swells4. The repeats also go short enough to work as chorus and slapback, up to a standard quarter note delay10. An adjustable low pass filter in the delay feedback lets you darken the repeats2.
Power and connections
The Joshua runs on 9 volts DC and draws 300 mA, which rules out battery power entirely: the manual states the pedal cannot be powered by a battery4. Jim Dunlop lists the Dunlop ECB003 9-volt adapter and the MXR Iso-Brick Pro, Iso-Brick and Mini Iso-Brick power supplies as compatible4. Guitar World's review lists the supplied adapter as 250 mA, while the manual's current draw figure is 300 mA; the two sources disagree, and the manual's figure is the one to build a power supply around42.
At 300 mA, this pedal needs a dedicated output on an isolated power supply. It will not run on a battery, and it is a heavier draw than most compact analog MXR pedals.
Connections are a standard input, a TRS output and the CTR jack2. The CTR jack takes an expression pedal to control settings or a tap switch to set the tempo of the echoes4. For stereo, use a TRS 1/4 inch cable from the output, which carries both channels27. Alternatively, set the CTR switch to its right position and the CTR jack becomes a right channel audio output, in which case the ring connection on the main output jack is muted4.
Other measured specifications from the manual: input impedance 1MΩ, output impedance 100 Ω, maximum input level +5 dBV, noise floor -97 dBV4.
What reviewers said
On That Pedal Show, Dan and Mick looked at how the Echo 2 button and the Divisions control interact, and their verdict on the core sound was blunt10:
"And that sounds flipping fabulous."
Videos
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Pete Thorn
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Questions
Can the MXR Joshua run on a battery?
No. The manual states plainly that the pedal cannot be powered by a battery. It runs on 9 volts DC through a power adapter, drawing 300 mA, so it needs a proper pedalboard power supply rather than a battery or a small daisy chain.
Is the MXR Joshua Ambient Echo true bypass?
Yes, by default. The footswitch toggles the pedal on and off in a true bypass configuration. When you engage Trails Mode, the pedal switches to buffered bypass so the repeats fade out naturally instead of cutting off abruptly when you switch it off.
Does The Edge use the MXR Joshua?
No. The Edge's delay sounds on U2's The Joshua Tree are the pedal's inspiration, and the name is a nod to that album, but it is not a signature pedal and he does not use it. It is MXR's own take on the vintage rack processors behind those tones.
Does the MXR Joshua have presets?
No. The guitar.com review lists the absence of presets among its minuses. You get six knobs, two push-buttons and a set of secondary functions, but no stored settings, so you dial in sounds manually each time.
How do you use the MXR Joshua in stereo?
Use a TRS 1/4 inch cable from the output jack, which carries both channels. Alternatively, set the CTR switch to its right position and the CTR jack becomes a right channel audio output, in which case the ring connection on the main output jack is muted.
Sources (10)
- MXR Joshua Ambient Echo review: impressive The Edge tones, guitar.com, 2024-06-14
- MXR Joshua Ambient Echo review, Guitar World, 2024-01-08
- The new MXR Joshua Echo delay pedal channels the rack sounds of U2's Edge, MusicRadar, 2024-01-03
- M309.pdf, Jim Dunlop, 2024
- Guitar Pedal X, Guitar Pedal X, 2024-01-09
- VOLUME (X)™ 8 PEDAL, Dunlop (jimdunlop.com)
- MXR Joshua Ambient Echo, Delicious Audio, 2025-05-19
- U2 in a box? MXR goes for "atmospheric perfection" with new Joshua Ambient Echo delay pedal, GuitarPlayer.com, 2024-01-03
- Guitar Pedal X, Guitar Pedal X, 2026-07-30
- MXR Joshua Echo, Peace Hill ODS Tube Preamp, MXR Super Badass OD & Beetronics Old Lion Meat Fuzz, That Pedal Show (YouTube), 2026-08-28
