Electro-Harmonix Holy Grail Plus

The Electro-Harmonix Holy Grail Plus is a digital reverb pedal released by Electro-Harmonix in 2008 and discontinued in 2022¹. It builds on the company's original Holy Grail, keeping that pedal's spring, hall and flerb reverbs and adding a room reverb, for four modes in total¹. Where the original Holy Grail gave you a single knob, the Plus adds a wet/dry blend control and a multifunction Amount knob, making it a more adjustable pedal while staying simple to run.

Four reverb modes, including Flerb

A single REVERB switch on the pedal chooses the reverb mode: SPRING, HALL, ROOM or FLERB¹. The first three cover the familiar ground. Vintage Guitar, reviewing the Epitome (a multi-effects pedal whose Holy Grail section carries the same Spring, Hall, Room and Flerb settings), described them as "Spring (classic surf sounds), Hall (big cathedrals), Room"².

Flerb is the odd one out, and the mode that gives the Holy Grail family its character. Electro-Harmonix describes it, on the related Nano Holy Grail, this way³⁴⁵:

MusicRadar's Alex Lynham, in a 2021 look at essential reverb pedals, put it more plainly: "Flerb mixes reverb with flange"⁵. For a player, that means the Flerb mode is less a conventional room sound and more a moving, swirling wash, closer in spirit to a modulated reverb than to a spring tank.

The controls

The Plus keeps the Holy Grail family's one-knob simplicity but splits the work across three controls and a footswitch¹.

The Amount knob is the heart of the pedal. Because its function changes with each mode, one knob covers decay (how long the tail lasts), damping (how the tail rolls off) and modulation speed (the movement in Flerb)¹. The Blend knob then sets how much of that reverb sits against your dry signal, from fully dry to fully wet, which is useful for ambient swells at the 100% wet end¹.

By comparison, the original Holy Grail had a single control. As JHS Pedals' Nick Loux described it: "It literally has one knob that says reverb, and when you turn it up, it adds more reverb"⁷. MusicRadar's Lynham noted that the single control "takes it from the ambience of a small room to a huge concert hall"⁵. The Plus gives you that same range plus independent control over the mix.

Power

The Holy Grail Plus runs on the EHX 9.6VDC power supply, with a 9.6VDC-200mA adapter included in the box¹. The pedal's current draw is 190mA¹.

The same 9.6VDC-200mA adapter arrangement carried across the family: the Holy Grail Nano, the Holy Grail Neo and the Holy Grail Max all shipped with one³⁸⁹.

History and versions

The Plus sits in the middle of a long line. The original Holy Grail, reviewed by Vintage Guitar in June 2002, was a digital reverb pedal made in the U.S. with three modes: spring, hall and flerb¹⁰. It used a buffered bypass rather than true bypass⁵. Premier Guitar's review of the later Cathedral noted that the Holy Grail series was the earlier Electro-Harmonix reverb line the Cathedral built on¹¹.

The Plus, released in 2008, took the original's spring, hall and flerb reverbs and added the room reverb, plus the Blend and multifunction Amount controls and true bypass¹. It was discontinued in 2022¹.

Around it sat several siblings:

The Neo arrived in March 2015, with Guitar.com reporting that Electro-Harmonix added it "responding to requests by pedalboard users for a compact pedal that includes plate reverb"¹³. The Max went a different direction, with Spring, Hall, Plate and Reverse modes¹⁴.

The Holy Grail story gained a new chapter in January 2026, when Josh Scott of JHS Pedals showed a lost Holy Grail prototype found in the Electro-Harmonix basement while researching a book on the company. On that video he also noted a circuit detail about later production: "The newer versions, they do not use the crystal chip because it's out of production"¹⁵.

What reviewers said

Published reviews of the Holy Grail line have been consistently positive about its spring reverb in particular. Vintage Guitar's 2002 review of the original was blunt¹⁶¹⁰:

The reviewer found the original delivered an authentic spring reverb sound that other, pricier pedals did not match¹⁰. Two decades later the spring setting still had fans: in Premier Guitar's 2025 review of the Epitome, whose reverb section is the Holy Grail's, the reviewer wrote:

The same reviewer reported using that spring setting on guitars, bass, vocals and synthesizers, and rated it damn close to replicating a true spring reverb¹⁶. MusicRadar's 2021 piece listed the Holy Grail among five essential reverb pedals, noting its three modes and its Flerb as a unique feature, while also flagging its buffered bypass as a trade-off on the original⁵. Gearnews' 2026 spring reverb buying guide still pointed players to the Nano Holy Grail's single-knob, three-way-switch simplicity, Spring, Hall and "the unique Flerb mode"¹⁷¹.

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