Electro-Harmonix Holiest Grail Instruction Manual

HOLIEST GRAIL

- DESCRIPTION -

The Holiest Grail is built around a high quality stereo reverb algorithm coupled with a
painstakingly developed simulation of spring reverb as found in guitar amps and dedicated
reverb tanks. The decay time, damping and diffusion parameters of the reverb can be
freely tweaked to design an infinite array of natural and unnatural sounding spaces. A
versatile pre-delay can be applied to the reverb, and a feedback control has been added to
the pre-delay to provide even greater sound-sculpting capabilities for spatial simulation
and/or experimentation.

As an aid to both live performance and recording, the box is able to store 8 user presets
and can be remotely controlled via MIDI. A standard expression footpedal can be used to
control the amount of signal sent to the reverb, a performance tool that can help
personalize the sound.

WARNING: Use only the 9VDC/500mA AC adapter the Holiest Grail comes
supplied with. Do not use any other AC adapters. Using other AC adapters, even
those made by Electro-Harmonix, could cause harm to the unit, the adapter or you.
The Holiest Grail does not use batteries.

INPUT

-------------------------------------------------------------------------------------------­INPUT GAIN Slider –

Converter. The green LED lights when there is sufficient level. The red LED will light when
clipping occurs.

presets.

The position of the INPUT GAIN Slider is not saved with the user

- CONTROLS/INDICATORS -

A control for setting optimal analog signal level into the A/D

Signal LED

depending on the strength of the input signal. The louder the signal the brighter this LED
will be.

Clip LED

the A/D Converter. Ideally you want the largest possible signal entering the A/D Converter
without clipping. One way to achieve the ideal signal level is to raise the INPUT GAIN Slider
until the CLIP LED starts to blink and then lower the INPUT GAIN Slider slowly until the
CLIP LED stops lighting.

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Pre-delay Controls

Reverb Controls

– Green LED above INPUT GAIN Slider. The Signal LED varies in brightness

– Red LED above INPUT GAIN Slider. The Clip LED lights when the signal clips

REVERB Design

TIME Slider –

instrument and the start of the reverb. For maximum usability, the slider has
two ranges of usage: between 0% and 50%, the predelay time can be adjusted
from 0 to 100 ms with an accuracy of approximately 1.5 ms. From 50% to
100%, the time ranges from 100ms to 440ms in 5 ms increments.

FEEDBACK Slider –

pre-delay before the reverb. At its maximum setting an infinite loop will be
created. At the lowest level the pre-delay simply delays the sound of the reverb
without any special effects. When the FEEDBACK Slider is set somewhere in the
middle, your original note will enter the Reverb a number of times.

DECAY Slider –

apparent size of space. At maximum setting an infinite reverb may occur,
depending on the other settings.

DAMPING Slider

setting of 0% has more damping and thus the reverb is muted. As the slider is
pushed up, the reverb sounds more bright and ‘open’. Higher settings (less
damping) also yield a longer reverb time.

DIFFUSION Slider

provide a density control to make subtle variations in the quality of the reverb

Controls the length of time between striking a note on your

Controls the amount of feedback that is re-circulated in the

Controls the length of the reverb time. This affects the

– Affects the frequency response of the reverb over time. A

– Works in conjunction with the other parameters to

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sound. At the lowest setting, the reverb has a grainier quality, while at the
maximum setting the reverb is at its most lush.

Output Mixer Controls

DRY Output Level Slider

– Controls the amount of dry signal sent to the
outputs. The dry signal is mixed into both the left and right output channels. At
maximum setting, 100% signal is output.

SPRING Output Level Slider

– Controls the amount of spring simulation
effect sent to the outputs. The spring signal is mixed into both the left and right
output channels. A higher setting makes the output “spring-ier.”

REVERB Output Level Slider

– Controls the amount of stereo reverb signal

sent to outputs. A higher setting yields more reverb signal.

PRESET Management

-------------------------------------------------------------------------------------------­PRESET/FREE MODE Slide Switch–

When in Preset Mode, programs can be saved and
loaded. When in Free Mode, all preset capability is disabled and all parameters are derived
from their slider values. (What you see is what you get!) In Free Mode, the Preset A and B
Footswitches have no function.

PRESET BANK Slider

– Selects the bank (1-4) to use when saving or loading presets. In

Free Mode, this slider has no function.

PRESET A Footswitch

– Tap this footswitch to load Preset A. Hold down the footswitch

for approximately 5 seconds to save a preset to position A.

PRESET B Footswitch

– Tap this footswitch to load Preset B. Hold down the footswitch

for approximately 5 seconds to save a preset to position B.

Preset A LED
Preset B LED

– Lit solid when Preset A is loaded. Blinks when saving to Preset A.
– Lit solid when Preset B is loaded. Blinks when saving to Preset B.

-BYPASS -

STATUS LED On/Off

– If lit, the reverb is active. If not, the unit is in True Bypass.

BYPASS Footswitch

– Toggles between processed sound and True Bypass. When the
Holiest Grail is in True Bypass mode, the Input Jack will be connected to the Main Output
Jack so the Bypassed signal will exit through the Main Output Jack. There will be no output
on the Stereo Output Jack when in True Bypass mode.

- Jacks -

INPUT -

This ¼” jack is the audio input.

MAIN OUTPUT -

This ¼” jack is the Main or left audio output. When the unit is

bypassed, this output contains the true bypass signal.

STEREO OUTPUT -

This ¼” jack is the right audio output or silence when in bypass.

EXP. PEDAL INPUT —

This ¼” input accepts an Expression Pedal with a TRS connection
or a Control Voltage (Between 0 and 5V) on TS connection. The Exp. Pedal Input controls
the level of signal into the reverb, useful for fades, swells, and other effects.

MIDI IN

- Standard 5pin DIN jack, MIDI Input.

MIDI OUT

- Standard 5pin DIN jack, MIDI Output.

PWR -

which is supplied with Holiest Grail.

This 2.5mm barrel jack supports a 9VDC/500mA external power supply adapter

- PRESET MODE -

When the unit is in Preset Mode, eight presets are available where one can store and recall
their very own personal sound settings. There are four banks each containing two presets.
The Preset Banks, 1 through 4, are selected using the Preset Bank Slider. The Presets, A &
B, within each bank are selected using the Preset Footswitches. Selecting a preset to load
or save requires choosing a combination of the bank slider and one of the preset

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