Electro Harmonix Holy Grail Max

A More Ambitious Holy Grail: The Spirit of the Original with "Studio" Textures

The Holy Grail Max retains the DNA that made the Holy Grail series famous: a reverb that's simple to set, immediately musical, with the essential Spring and Hall modes. It takes the concept further by adding a Plate inspired by studio reverbs (dense, smooth, very "enveloping") as well as a Reverse for pads and reverse attack effects. The result: a versatile guitar reverb pedal, without menus or unnecessary sub-functions, designed to transition from vintage amp sounds to modern ambiances.

For Whom, Which Styles, and In What Contexts?

The Holy Grail Max is aimed at guitarists (beginners and pros alike) who want to enhance their clean tone, add depth to crunch sounds, or establish a true spatial signature in rhythm or lead playing. The Spring excels in surf, vintage rock, blues, while the Hall suits wide sounds (pop, post-rock, worship, solo). The Plate is perfect for clean, hi-fi textures in the studio, and the Reverse opens doors to shoegaze, ambient, experimental worlds.
Live, it adjusts in seconds and easily sits at the end of the chain (or in an amp's effects loop if you prefer reverb after preamp distortion). In home studio, it excels at thickening a mono take without complicating the session.

Controls, Modes, and Operation: Electro-Harmonix Efficiency

The Holy Grail Max goes straight to the point: a REVERB selector chooses the ambiance type (Spring, Hall, Plate, Reverse), a BLEND potentiometer adjusts the wet/dry mix, and a TIME potentiometer sets the reverb length. This multifunction control makes all the difference: on Spring/Hall/Plate, TIME controls the decay (the tail length); on Reverse, it determines the attack time (the delay/time before the reversed reverb fully "appears").
The footswitch activates the effect with true bypass to preserve signal integrity when the pedal is off. Another strong point: the mix control maintains a consistent volume feel, and your dry signal remains analog through the pedal, helping to keep attack and dynamics even with very wet settings.

Sound Character

Spring delivers that lively, slightly gritty, "amp-like" quality that highlights open chords, picking, and rock'n'roll riffs. Hall stretches the space with a broader sense of depth, ideal for adding breadth without radically changing your EQ. Plate offers a denser, silkier, very homogeneous reverb, perfect for modern clean tones, arpeggios, and large pads: at high TIME settings, you can achieve very long tails, like an ambient "wash." Finally, Reverse provides a sucked-back/reversed effect, excellent for intros, transitions, or thickening a riff by creating a reverb that seems to rise toward the note.
Note: the Holy Grail series has appeared on many pedalboards, notably with guitarists known for their textures and ambiances (such as John Frusciante or Kevin Parker), which speaks volumes about the immediate usability of these reverbs in real-world situations.

Technical specifications

Effects	Reverb	Type	sector
Technology	Digital	Use	electric guitar
Format	Pedal	Color	Black

Modes	Spring, Hall, Plate, Reverse	Dimensions	102 x 121 x 89 mm
TIME potentiometer	decay (Spring/Hall/Plate) or attack time/Reverse time (Reverse)	Weight	290 g
Input	6.35mm Jack	Required power supply	9 V DC (center negative)
Output	6.35mm Jack	Consumption	80 mA
Power input	DC connector (center negative)	Adapter supplied	9.6 V DC / 200 mA
Input impedance	1 megaohm	Battery operation	no
Output impedance	550 ohms