Radial Engineering Firefly User's Guide

®

Firefly

Tube 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]

True to the Music

www.radialeng.com

True to the Music

®

®

™

Radial Firefl y

Tube Direct Box

Table of Contents Page

Feature set ...................................................................................................................1

Overview.......................................................................................................................3

Making connections ......................................................................................................4

Setting Up the Firefl y for Various Instruments ..............................................................8

Setting the output controls ............................................................................................9

Remote switching and mute with JR•2 .........................................................................10

Rackmounting kit ..........................................................................................................11

Specifi cations ...............................................................................................................11

Block diagram ...............................................................................................................12

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

Congratulations and thank you for purchasing the Radial Firefl y! You are now the proud
owner of what is arguably the most exacting direct box ever made. The Firefl y combines state
of the art electronics with a tube drive and transformer coupled output to produce a clean
warm tone. And hidden inside are a ton of very cool features designed to enable the Firefl y
to be used in all types of applications for all types of instruments.

Although you will fi nd the Firefl y to be super easy to use, we recommend you to take a few
minutes to read the manual to ensure you understand the various features and get the most
out of this amazing device. If after reading the manual you need further clarifi cation, please
visit the Firefl y F AQ page on the Radial web site. This is where we post questions and answers
from users along with the latest updates. Then, if you still do not fi nd what you are looking
for, we invite you to send an email to [e-mail] and we will do our very best to get
back to you promptly.

Now get ready to plug into one of the most enjoyable pieces of audio equipment ever!

Radial Engineering Ltd.

Fire y™ Tube Direct Box

®

FRONT PANEL FEATURE SET

True to the Music

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1. TRIM-A & B: Input level controls used to match the gain between the two instruments.

2. SELECT: Selects the active input for fast instrument changes. The illuminated LED

indicates the active input.

3. MUTE LED: Indicates when the mute function is active. Remote controlled via the
optional JR•2 footswitch.

4. DRAG: Used to retain the natural feel of the instrument by adjusting the load for
passive pickups.

5. LOW CUT: Variable high-pass fi lter rolls off low frequency resonance that can cause
feedback or muddy up the sound.

6. LEVEL: Level control for the balanced XLR output. Variable from mic to line-level.

7. PROTECTIVE FRONT LIP: The enclosure design create a protected zone around the

switches and knobs to prevent damage.

8. POWER: Locking 5-pin XLR power supply connection. The external supply helps
reduce noise and delivers +/-16 volts (1600mA) that is internally stepped up to 48V for
the tube.

9. OUTPUT: Balanced XLR output connects to the PA or recording system. Transformer
isolated to eliminate hum & buzz caused by ground loops.

Radial Engineering Ltd.

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Fire y™ Tube Direct Box

True to the Music

REAR PANEL FEATURE SET

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98

10. 180º POLARITY: Inverts the signal polarity by fl ipping pins-2 and pin-3 on the XLR
output. Used to reduce resonant peaks that cause feedback.

11. GROUND LIFT: Disconnects pin-1 at the XLR out. Helps reduce noise caused by
ground loops.

12. AUX PRE/POST: Changes the signal path of the ¼” AUX OUT. When set to the
inward position (pre) the AUX OUT provides a direct clean buffered feed from your
instruments. When set to the outward position the AUX OUT is like the main XLR
output, post tube stage, fi lter section and insert loop.

13. TUNER OUT: Always-on, high-Z output used to connect an electronic tuner.

14. REMOTE: Used to connect the optional JR2 remote footswitch. When connected, this

lets you select the active input channel or mute the Firefl y for tuning.

15. AUX OUT: High-Z thru-put for stage amp. Confi gurable ‘pre or post’ tube and insert.

16. INSERT: Buffered effects loop uses standard ¼” TRS send & receive cable to interface

guitar pedals and studio rack effects.

17. INPUTS A & B: High-Z inputs lets you switch between two instruments for quick on­stage changes. The input level is set using the TRIM-A & B controls.

18. AUX THRU (side panel): Recessed switch engages transformer
isolation for ¼” AUX OUT to eliminate hum and buzz caused by
ground loops.

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Radial Engineering Ltd.

2

Fire y™ Tube Direct Box

®

True to the Music

OVERVIEW

The Firefl y is a direct box. What this means from a ‘technical’ standpoint is that the Firefl y is
designed to deliver the sound of the instrument to the recording system or PA without intro­ducing artefact. But the sheer fact that the Firefl y employs a tube as part of the circuit means
that the tube will add warmth and natural even order harmonics to the signal. Technically,
DI boxes like the Radial JDV™ are much more accurate while the Firefl y is designed to add
character. That being said, the Firefl y remains a direct box and therefore, it must perform the
task... and do it well.

The primary task of a direct box is to convert the unbalanced high impedance signal from
an instrument to a balanced low impedance signal suitable for a PA system or for recording.
The output from a direct box is usually equivalent to a mic level signal. This enables the DI to
‘comfortably live’ along side microphones, using the same mic splitters, mixing console inputs
and microphone preamps. Standardizing the signal makes it easy to switch around cables
on hectic stages when trouble shooting. And although the Firefl y is able to produce a much
hotter output than a typical DI box, turning down the master volume is all that is required to
match things up.

Several extra features have been added to the Firefl y to increase functionality on stage and
better adapt to the various instruments that may be connected. For instance; two inputs make
it easy to swap instruments. Drag Control lets you adjust the load on the pickup for optimum
signal transfer. The 4 meg-ohm input impedance lets you properly load piezo pickups so that
they sound right. You can also add options such as a remote control for input switching and
quiet tuning on stage. And of course you can rack mount the Firefl y in a single space using
the optional 19” rack adaptors.

Radial Engineering Ltd.

TYPICAL SETUP

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Fire y™ Tube Direct Box