Radial Engineering Head Load User's Guide

®

Guitar Amp Load Box and Direct Box

True to the Music

User Guide

®

www.radialeng.com

Radial Engineering Ltd.
1588 Kebet Way, Port Coquitlam
British Columbia, Canada, V3C 5M5
tel: [phone] • fax: [phone]
email: [e-mail]

www.radialeng.com

IMPORTANT SAFETY & USER NOTICE

! !

It is your responsibility to confi rm the Headload is connected properly before
operating your amplifi er. If you are unsure about connecting or operating the
Headload consult a qualifi ed technician or see your dealer. Damage caused by
improper operation is not covered under the warranty. See the back cover for
warranty details.

ALWAYS USE THE HEADLOAD WITH A SPEAKER CABINET

A speaker cabinet must be connected to the Headload at all times. It is pos-

sible to use the Headload as a dedicated load box without a speaker connect-

ed but this is not a recommended practice as you may damage the Headload

or your amp if the LOAD SWITCH is not in the propper setting. Damage due

CAUTION - USE OF THE HEADLOAD WITH AMPLIFIERS WITH BRIDGED

OR BALANCED SPEAKER OUTPUTS IS STRICTLY PROHIBITED.

Although these types of circuits are rarely employed on instrument amps, us­ing the Headload with them can cause an electrical shock. Please consult the
amplifi er manufacturer to ensure the power output section of your amp is not
bridged or balanced. As we have no control over the use of these amps, for legal
liability reasons, Radial Engineering Ltd. strictly prohibits use of the Headload
with such amplifi ers.

CONNECTING YOUR RADIAL HEADLOAD

BEFORE CONNECTING OR DISCONNECTING

to misuse is not covered under the Radial 3-year warranty.

PLEASE READ BEFORE

ALWAYS TURN YOUR AMPLIFIER OFF

It is normal for your Headload to get warm during operation. The Headload fan
draws cool air in through the front, top and sides and exhaust hot air out through
the rear. Do not block the air vents and always provide a minimum of 2.5cm (1”)
of open air space around the Headload when in use.

As with all products capable of producing high sound pressure levels (SPL), users
must be very careful to avoid hearing damage that may occur from prolonged
exposure. This is particularly important as it applies to headphones. Prolonged
listening at high SPLs will eventually cause Tinnitus and can lead to partial or
complete loss of hearing. Please be aware of the recommended exposure limits
within your legal jurisdiction and follow them very closely. The user agrees that
Radial Engineering Ltd. remains harmless from any health effects resulting from
the use of this product and the user clearly understands that he or she is entirely
responsible for the safe and proper use of this product. Please consult the Radial
Limited Warranty for further details.

DO NOT BLOCK THE AIR VENTS

HEADPHONE SAFETY WARNING

®

™

Radial Headload

Guitar Amp Load Box

User Guide

Table of Contents .....................................................Page

Overview................................................................................................1

Features and Functions ......................................................................... 3

Unpacking and Optional Rackmount Kit ................................................ 5

Getting Started ......................................................................................6

Connectiing the Amp and Speaker ........................................................ 7

Using the Attenuator/Loadbox .............................................................. 8

Connecting the JDX Balanced Outputs ................................................. 9

Using the JDX......................................................................................10

Using the Phazer ................................................................................. 11

Specifi cations ......................................................................................12

Radial Limited Warranty ....................................................... Back Cover

Congratulations and thank you for purchasing the Radial Headload, an
innovative speaker power attenuator, loadbox and guitar amp direct box.
The Headload is a unique tool that lets you drive your amp hard for great
tone while keeping speaker volume low. This lets you optimize the tone
from your guitar amplifi er without having to perform at ear-blistering levels.

The Headload features a built-in JDX amp DI that captures the natural
tone of your amplifi er/speaker and interfaces it with professional PA and
recording systems. The Headload has also been equipped with a Radial
Phazer. This phase adjustment tool lets you time-align the JDX direct
output with a microphone to deliver incredibly natural tones, or when
pushed to extreme, create over the top effects.

The Headload is easy to use, however it differs signifi cantly from standard
attenuators. We recommend you take a few minutes to read this manual
before operating your Headload. Should you have any questions, check
the Headload FAQ page at www.radialeng.com. This is where we post
questions from users and informational updates. If you would like to
share your experience with Radial products we invite you to contact us
at [e-mail] or on Facebook at www.facebook.com/radialeng.

®

True to the Music

OVERVIEW

The Headload is a combination load box and attenuator that is capable of handling up to
120 watts RMS of continuous power and peaks of 180 watts. Inserted between the head and
cabinet, it allows the guitar amp to be driven hard while reducing the output level to reduce
the sound pressure on stage or provide the means for quiet recording in the studio. This
enables the artist to optimize the tone from the guitar amplifi er without having to perform at
ear-blistering levels.

HEADPHONES

FROM AMP

AMP

TO SPK

SPK CAB

JDX Section

In order to ensure greater consistency from gig to gig, the Headload is equipped with a Radial
JDX Reactor direct box. This captures both the signal from the head plus the reactive load
from the speaker cabinet for a more natural feel. The JDX has two balanced line outputs.
This fi rst is Pre-EQ and intended to feed the standard JDX tone to the FOH mixing console.
The Post-EQ output is intended to feed the monitor system allowing the player to modify the
tone using the JDX EQ and cabinet emulation fi lters.

HEADPHONES

AMP

F.O.H

Radial Engineering Ltd.

MONITORS

FROM AMP

TO SPK

SPK CAB

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Headload Guitar Amp Load Box

True to the Music

Phazer Section

For engineers that prefer to combine a direct feed with a microphone, the Headload has also
been equipped with a Radial Phazer. This phase adjustment tool lets you time-align the JDX
direct outputs with the microphone to deliver incredibly natural tones, or when pushed to
extreme, create over the top effects.

®

AMP

TO SPK

MIC

SPK CAB

F.O.H

HEADPHONES

FROM AMP

MONITORS

Its purpose is to shape the sound by shifting the phase of the JDX signal from the Head­load in relation to a microphone signal allowing you to tune the overall phase-response of
the combined signals. The diagrams below show the phase offset created by the JDX and
microphone signals. The Phazer is used to shift the JDX signal and align the fundamental
waveforms.

JDX Signal

Mic Signal

JDX Signal

Mic Signal

Time

Phase Shift

Time

Phase Shift

The Radial Phazer is capable of shifting the phase continuously over the complete 360°
range. You simply dial in the amount of phase shift that sounds best to your ears.

Radial Engineering Ltd.

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Headload Guitar Amp Load Box