Groove Tubes Studio Series

Operators GuideTheBrickTM

Tube Microphoneand Instrument
Preamplifier

Congratulations!

Specs

We believe you’ve justpurchased the world’s finest
portable tube mic andinstrument preamplifier available
anywhere, for any price. The Brickgot it’s name when noted engineer
Greg Ladanyi had commented that
“this thing is built like a brick”!

Mic Input
Nominal 150 Ohms
sourceReflected Load presented
to source is 600 Ohms
For use with:
Condenser Mic
Dynamic Mic
Ribbon Mic

Inst Input

Your new GT Brick can be used for a multitude ofaudio signal amplification and distribution chores:
1 - A Tube Mic Pre for Studio:
The Brick will work warming wonders for all
dynamic, condenser, or ribbon type studio grade
microphones in any recording environment. The
Brick can provide up to +55dB of tube gain to any
studio mic. This is more than enough gain for direct
recording into computer based recording systems
or traditional analog formats.
2 - A Tube Mic Pre for Stage:
Many engineers have noticed how our ViPRE tube
mic pre added so much depth to dynamic mics
popular for live perforrmance. They asked us todevelop a portable and road worthy mic pre that
could work the same audio magic for a dynamic or
wireless mic in live performance applications. That
is why we designed the Brick capable for stage or
studio use with its unique rugged steel package
and special internal construction features.
The Brick is a compact powerhouse preamp thatwill noticeably improve the tone of all common
stage mics, either dynamic, condenser or wireless.
The Brick’s 3 internal tubes and massive custom
output transformer can drive a signal 100’s of feetwith no loss...and improve any performance. Now
you can get studio grade tone and performance on
any stage!
3 - A Tube Line Driver:
The Brick can input an unbalanced line or
instrument level signal and output a balanced
signal that will add depth and warmth to any
recording. Its balanced and floating output will
arrive at your mixing console or recorder warm, fat,and totally unaffected by the journey.

4 - A Tube Instrument Preamp for Studio:
The Brick has the same tonal feature as its
forerunner, the GT DITTO box. Just plug in yourelectric or acoustic-electric guitar, electric bass,
synth or keyboard to amplify and drive a balanced
and floating signal to your mixer or recorder. The
brick is capable of amplifying up to +30dB with its
3 tube cascode gain circuitry. You may use theBrick as a neutral D.I. (with Gain at “0”) and thesignal level will be unchanged. Or, use the Brick as
a preamplifier (Gain up to +30dB and you will notneed any additional gain from your board). The
Brick will preamplify any line or instrument signals
directly into a +4 or -10 Line input stage of yourmixer or recorder.
5 - A Tube Instrument Preamp for Stage:
Hear the difference a real tube preamp can makefor your live instrument performances. The Brickoffers those sweet tube dynamics and warming
properties to all live stage performances. You willfind this especially helpful for those instrument
wireless systems that can sound thin. The Brickshrugs off that thin wireless tone and replaces itwith Fat! Once you play out live with a Brick, you’ll
never go back!
The Brick also adds clarity, punch, and tube warmth
to the wide range of electro-acoustic guitar pickups
that can sound brash and brittle....while roundingout the boom of an electric bass. The Brick will
provide added clarity, dimension, and true dynamic
response of tubes when compared to the “pseudotube”, solid state or passive DI boxes.

Three megohm
High Impedance,
For use with :Electric Guitar
Electro-Acoustic Guitar
Piezo-electric Pickups
Electric BassElectronic Keyboard
Electronic Synthesizer
LIne Level Signals

Output Level
Nominal + 4 dBm
Maximum +16 dBm
terminated at 600 Ohms

Dynamic Range
118 dB

Available Gain
INST= + 30 dB
MIC = + 55 dB

Bandwidth
6 Hz to 22K Hz@ Minimum Gain(+0 dB and -3 dB)

NoiseA Weighted
EIN -90 dB

Total HarmonicDistortion.013% @ +4 dBm

Phantom Power+48 volts DCMic Polarity
PIn 2 Positive

AC
Primary input voltage isInternally Selectablebetween 120v and 240v
50-60 Hertz

FUSE
1 Amp @ 120 volts
1/2 Amp @ 240 volts

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The Brick Operators Guide

Other Features:
Signal Ground Lift:
Engaging this switch to the “0” position will isolate
your signal ground from your Earth ground and can beused to “float” your signal in certain environments.
This switch does not unbalance your XLR transmission
line or add induction of hum or noise.

Operating Instructions:
Mic Preamp:
Insert your Lo Z microphone into the XLR jack labeled“MIC INPUT” on the front panel of the Brick. The Brickautomatically adds +25dB of gain with the Gain control
set fully to the left. As you rotate the Gain control tothe right, the Brick will gradually increase the gain upto +55dB.
Instrument Preamp:
Insert your instrument into the far left 1/4” input
labeled “INST INPUT”. There is zero gain added(ie: Unity Gain”) when the Gain control is fullycounterclockwise. Rotating the Gain control to theright will gradually increase the amplification factor up
to +30dB.

Gain Control:
This control allows you to set the Brick for “0” dB, orunity gain, for the “INST INPUT” signals. The Brick’s
internal all tube amplifier can add up to +30dB in thefull clockwise position
The “MIC INPUT” signals will be automatically
amplified @ +25dB and can be increased to up to+55dB with the Gain control in the full clockwise
position.
Phantom Power:
Activating this switch will add +48vdc to the XLR jackfor powering common phantom powered condenser
microphones.
On/Off switch
External fuse holder provided on the opposite sidefrom the audio input/output face panel.

Instrument DI:Insert your instrument into the far left 1/4” input
labeled “INST INPUT”. There is zero gain added(ie: Unity Gain”) when the Gain control is fully
counterclockwise.
You may pass your instrument signal onto anotherstage amp by using the “INST THRU” 1/4” output jacklocated directly to the right of the “INST INPUT” jack.
This will not affect the Brick’s preamplification gain ortone.
Line driver:Same rules apply as for the Instrument D.I. above. The
Brick passes unity gain when the Gain control is set in
the fully counterclockwise position.
Trading tube gain for solid state gain is almost always
desirable and will result in a better soundingperformance.

NOTE: The balance output signal from the Brick uses Pin 2
as “hot”, consistent with the AES standard. You may"unbalance" this signal and run it single ended but humand noise induction may result depending on theenvironment conditions.

©2003 Groove Tubes LLC. All rights reserved. Groove Tubes, The Brick byGroove Tubes LLC. All specifications subject to change without notice.

GROOVE TUBES LLC

Hear the Difference!

Studio Products1543 Truman Street
San Fernando, California 91340 USA
Tel 818 361 4500
Fax 818 365 9884

www.groovetubes.com