MTX Audio POWER AMPLIFIE User Manual

POWER
AMPLIFIER

OWNER’S
MANUAL

POWER AMPLIFIER OWNER’S MANUAL

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CONGRATULATIONS...

on your purchase of a new MTX Audio
Thunder Amplifier! MTX has long been the
industry leader in mobile enclosures and
speakers, and we have reached new heights
with the development of the new MTX
Thunder amplifiers. You couldn’ t have chosen
a more reliable, powerful, or better perform­ing amplifier. In fact, we back up every
Thunder amplifier with a three-year warranty
if installed by an authorized MTX Audio retail­er (see the warranty statement).

Your new MTX Thunder amplifier was
designed, built and thoroughly tested at our

state-of-the-art electronics manufacturing
facility. We manufacture every amplifier using the
latest Intelligent Surface Mount Technology. Some
of the advantages of the new design are its signifi­cant improvements to the amplifier’s electrical and
mechanical properties. ISMT devices feature sub­stantially shorter internal and external lead lengths.
This reduces stray capacitance and inductance,
which results in cleaner and more accurate musical
reproduction with significantly less noise interfer­ence. The ISMT mounter produces amplifier boards
with smaller and lighter components, which are
more resistant to vibrations inherent in the automo­tive environment.

A word about power ratings. It is important for you
to know how they stack up. MTX has chosen the
most honest, most conservative way to rate our
amps. We show you the RMS power, at 12.5 volts,
and dynamic power at 14.4 volts. However, we go
above and beyond the call of duty. We test each
amplifier. The technician records the “actual”
power output, and records this number on your
Certified Performance Certificate. The amplifier
must meet or exceed the rated specification before
we’ll ship it. No questions. No exceptions.

We want to ensure you get continuous high per­formance from your MTX Thunder amplifier, so we
recommend that you have it professionally installed
by your authorized MTX dealer.

HOW TO USE THIS MANUAL

If you are installing this amplifier yourself, we rec­ommend that you read the manual cover-to-cover
before you install it. Familiarize yourself with the
features and details on the input and output panels.
Make sure you have all the equipment you need.
Then follow the step-by-step installation instruc­tions included. Sample installation diagrams may be
found on our website:

mtx.com

If you have any questions, write or call us:

MTX Audio

4545 E. Baseline Rd. Phoenix, AZ 85042

602-438-4545 • 800-CALL MTX

[e-mail]

mtx.com

Please take a moment to register your purchase
on-line at mtx.com.

Please also record the serial number of your
amplifier in the space provided below and keep this
manual for future reference, as well as your sales
receipt as proof of ownership. (The serial number
of your amplifier is marked on the bottom of its
metal chassis.)

SERIAL NUMBER:
DATE OF PURCHASE:

Introduction

ENGLISH

• Thunder Amplifiers are Covered by One or More
of the Following United States of America
Patents: #5,598,325, #5,631,608, #5,783,970

• Acoustically Seamless Turn-On/Turn-Off

• Adjustable Input Sensitivity

• Anti-Shock PCB Mounting Design

• High Powered Transformer

• Intelligent Surface Mount Technology

• Nickel-Plated, Heavy Duty Terminal
Block Connectors

• Patented PWM MOSFET Switching Power Supply

• Real Time Computerized Protection Circuit

• Unique Rubber Insulated Iso-Feet™

• 12dB/Octave Stereo High Pass, 24dB/Octave
Mono Low Pass Crossover

• Bridgeable Circuit Design

• Buffered RCA Output for Daisy-Chaining
Multiple Amplifiers

• Left and Right Individually Adjustable
Input Sensitivity

• Patented Class A 100% Discrete Driver
Circuit Topology

• Patented Pure N-Channel Design

• Thunder EQ Bass Enhancement

• Tracking RCA Crossover Output

• Smart-Engage™ Auto Turn-On for Easy
Integration with Factory Head Units When Using
Speaker Level Inputs (THUNDER342)

• Speaker and Low Level Inputs (THUNDER342)

Features

Specifications

THUNDER342

• RMS Power measured at 12.5 Volts DC:
60 Watts x 2 into a 4 Ohm load with less than 0.1% Thd+N
120 Watts x 2 into a 2 Ohm load with less than 0.1% Thd+N
240 Watts bridged into a 4 Ohm load with less than 0.1% Thd+N

• Dynamic Power measured at 14.4 Volts DC:
85 Watts x 2 into a 4 Ohm load
170 Watts x 2 into a 2 Ohm load
340 Watts bridged into a 4 Ohm load

• Signal to Noise Ratio: ≥110dB A-Weighted

• Damping Factor: >200

• Frequency Response: 20Hz-20kHz ± 0.25dB

• Maximum Input: 8Vrms

• Thunder EQ: Variable Bass Boost (0-18dB) centered at 40Hz

• Crossover: Variable 40Hz to 200Hz, 12dB/Octave Stereo
High Pass, 24dB/Octave Mono Low Pass, or Full Range

• Dimensions: 10.7" x 9.75" x 2.1" (27.2cm x 24.8cm x 5.3cm)

THUNDER502

• RMS Power measured at 12.5 Volts DC:
90 Watts x 2 into a 4 Ohm load with less than 0.1% Thd+N
180 Watts x 2 into a 2 Ohm load with less than 0.1% Thd+N
360 Watts bridged into a 4 Ohm load with less than 0.1% Thd+N

• Dynamic Power measured at 14.4 Volts DC:
125 Watts x 2 into a 4 Ohm load
250 Watts x 2 into a 2 Ohm load
500 Watts bridged into a 4 Ohm load

• Signal to Noise Ratio: ≥110dB A-Weighted

• Damping Factor: >200

• Frequency Response: 20Hz-20kHz ± 0.25dB

• Maximum Input: 8Vrms

• Thunder EQ:Variable Bass Boost (0-18dB) centered at 40Hz

• Crossover: Variable 40Hz to 200Hz, 12dB/Octave Stereo
High Pass, 24dB/Octave Mono Low Pass, or Full Range

• Dimensions: 12.6" x 9.75" x 2.1" (32.1cm x 24.8cm x 5.3cm)

THUNDER942

• RMS Power measured at 12.5 Volts DC:
175 Watts x 2 into a 4 Ohm load with less than 0.1% Thd+N
350 Watts x 2 into a 2 Ohm load with less than 0.1% Thd+N
700 Watts bridged into a 4 Ohm load with less than 0.1% Thd+N

• Dynamic Power measured at 14.4 Volts DC:
235 Watts x 2 into a 4 Ohm load
470 Watts x 2 into a 2 Ohm load
940 Watts bridged into a 4 Ohm load

• Signal to Noise Ratio: ≥110dB A-Weighted

• Damping Factor: >200

• Frequency Response: 20Hz-20kHz ±0.25dB

• Maximum Input: 8Vrms

• Thunder EQ: Variable Bass Boost (0-18dB) centered at 40Hz

• Crossover: Variable 40Hz to 200Hz, 12dB/Octave Stereo
High Pass, 24dB/Octave Mono Low Pass, or Full Range

• Dimensions: 17.8" x 9.75" x 2.1" (45.3cm x 24.8cm x 5.3cm)

POWER AMPLIFIER OWNER’S MANUAL

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1. Turn the gain control on the amplifier all the way
down.

2. Turn up the volume control on the source unit to
approximately 3⁄4 of maximum.

3. Adjust the gain control on the amplifier until
audible distortion occurs.

4. Adjust the gain control down until audible distor­tion disappears.

5. Follow steps 3-4 for other gain control settings if
applicable.

6. The amplifier is now calibrated to the output of
the source unit.

Installation

Any deviation from the connection specifications recommended may cause serious damage to the amplifier,
speakers and/or vehicle electrical system. Please double-check the connection before turning the system on.

1. Disconnect the vehicle’s negative battery connection.

2. Place your Thunder amplifier at the predetermined mounting location. Using a felt pen, mark the exact
position of the mounting holes on the mounting surface. Set the amplifier aside. Use a sharp, precise blade
to cut small circles in the carpet and padding around the four marks denoting your mounting holes to
expose the metal underneath. Use a center punch to make an indentation in the metal to ensure that you
drill the exact position for the screws. Drill the four holes as marked.

3. Temporarily mount your Thunder amplifier.

4. Run a power cable from the vehicle’s battery through the firewall and through the interior of the vehicle
connecting one end to your Thunder amplifier’s +BATT terminal and connect the other end to the positive
post on the battery.

Note: Install a circuit breaker/fuse within 18" of the battery. This effectively lowers the risk of severe damage
to your vehicle should a short circuit ever occur in the audio system. Do not install the fuse in the fuse hold­er until all installation steps have been completed.

5. Find a good ground spot on the vehicle’s chassis and remove the paint to reveal bare metal at the contact
point. Attach the ground wire to that contact point and connect the other end of the ground wire to the
GND terminal of your Thunder amplifier.

6. Connect a Remote Turn-on wire from your source unit to your Thunder amplifier’s REM terminal (14 or 16
gauge wire). If your source unit does not have a dedicated Remote Turn-on lead, you may connect to the
source unit’s Power Antenna lead.

7. Connect RCA cables from your source unit to your Thunder amplifier’s RCA input jacks. If RCA (low level)
output is not available, connect the included speaker (high level) connector (Thunder342) to the speaker
wires from the source unit.

8. Connect your speakers to your Thunder amplifier’s speaker terminals using 12 gauge minimum speaker
cable.

9. Double-check all the previous installation steps, in particular, the wiring and component connections.
Securely mount the amplifier. If everything is in order, reconnect the vehicle’s negative battery connec­tion and begin adjusting your amplifier.

Note: Be sure that the Gain Level on the amplifier is turned all the way down (counter clockwise) before pro­ceeding with adjustments.

Common Oversights

• The battery ground should remain DISCONNECTED at all stages of installation.

• Do not begin drilling until you have put your Thunder amplifier aside. Using the amplifier as a drilling guide
may cause irreparable damage to the amplifier and void your warranty.

• Do not route any wires underneath or outside the vehicle body.

• Route signal wires (RCAs from source unit, speaker wires, etc.) away from power wires (power, ground,
etc.) to avoid ground loops and other sources of noise.

Adjusting the Gain

Typical Speaker

Wiring Configurations

Troubleshooting Guide

Read this if you wanna be a do-it-yourselfer or give us a call at 800-CALLMTX.

PROBLEM CAUSE SOLUTION

No LED indication No +12V at remote connection Supply +12V to terminal

No +12V at Power connection Supply +12V to terminal
Insufficient ground connection Verify ground connection
Blown power fuse Replace fuse

LED on, no output Volume on head unit off Increase volume on head unit

Speaker connections not made Make speaker connections
Gain control on amplifier off Turn up gain
Signal processing units off Apply power to signal processor
All speakers blown Replace speakers

Output distorted Head unit volume set too high Lower head unit volume

Amplifier gain set too high Lower amplifier gain

Balance reversed Speakers wired L + R reversed Wire speakers with correct

orientation

RCA inputs reversed Reverse RCA input

Some balance reversed Some Speakers wired L + R Wire speakers with correct

reversed orientation
Some RCA inputs reversed Reverse appropriate RCA inputs

Bass is weak Speakers wired out Wire with correct phase

of phase
Not using MTX woofers Buy MTX woofers

Blowing fuses Excessive output levels Lower volume

Amplifier defective Return for service

Stereo Amplifier
Bridge Mode Application
Impedance Requirement

4 ohm bridge minimum
2 ohm stereo minimum

8 ohm

8 ohm

+ - - +
L L R R

AMP

Two 8 ohm Speakers

OK

4 ohm

4 ohm

+ - - +
L L R R

AMP

Two 4 ohm Speakers

not

ok

POWER AMPLIFIER OWNER’S MANUAL

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1. Gain Controls – These controls are used to match the input sensitivity of the amplifier to the particu­lar source unit that you are using. The controls are factory set to 1Vrms.

2. RCA Input Jacks – These RCA input jacks are for use with source units that have RCA or Line Level
Outputs. A source unit with a minimum level of 200mV is required for proper operation. The use of high qual­ity twisted pair cables is recommended to decrease the possibility of radiated noise entering the system.

3. Speaker Level Inputs – This input, found on the Thunder342 will allow the amplifier to operate from
source units with speaker-level outputs. Output speaker leads from the source unit should be tied directly
to the wire harness provided with the amplifier.

Wire harness color codes:

Grey / Black = Source units right negative (-) White / Black = Source units left negative (-)
Solid Grey = Source units right positive (+) Solid White = Source units left positive (+)

With the Smart-Engage™ auto-turn circuit, a remote turn-on wire is not necessary when connecting the
speaker-level input wire harness to a high powered source unit. The amplifier will automatically turn on
when music is received.

4. Frequency Control – This control is continuously adjustable from 40Hz through 200Hz. Factory setting
is at 40Hz.

5. Crossover Select –This switch determines what type of signal comes out of the amp. If you select high
pass, the crossover slope is 12dB/stereo. If you select low pass, your crossover slope will be 24dB/mono.
Available crossover frequencies are 40-200Hz.

6. Thunder EQ – This equalization circuit is used to enhance the low frequency response of the vehi­cle’s interior. With up to 18 dB of boost and centered at 40Hz, the Bass EQ can be adjusted to meet your
own personal taste.

7. Compression Circuit – This new circuit, found on the Thunder942 and Thunder502, prevents the ampli­fier from going into clipping, even at high SPL levels. The compression circuit allows the listener to play the
amplifier at high volume levels, yet protects the speakers against the potential damage that can occur dur­ing dynamic musical passages. The circuit is switchable on/off, for those SPL competitors who run their
amplifiers into clipping on purpose. Warning: Damage to speakers may occur when the compression circuit
is in the off position.

8. EBC 2 – The EBC, or Electronic Bass Control, allows a remote bass control to be adjusted from the dri­ver’s seat. If the optional EBC is installed, the bass level will be able to be adjusted to overcome noise and
other interference. With EBC 2 multiple amplifiers can be controlled. (Thunder942 and Thunder502)

9. RCA Output Jacks and Switch – These RCA outputs allow for a signal to be sent to other ampli­fiers in a daisy-chain configuration. You can select whether the signal should be high pass , low pass or
full range. In low pass mode, the RCA outputs allow for multiple bass amplifiers to be level controlled using
one EBC.

Input Panel Layout

❶

❻

❹

❺

❷❾

❾

❸

❶

❻

❹

❺

❷❾

❾

❽

❼

❶

❻

❹

❺

❷❾

❾

❽

❼

POWER AMPLIFIER OWNER’S MANUAL

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1. Fuses - For convenience, all amplifiers utilize ATC type fuses. For continued protection in the event that
a fuse blows, replace the fuse only with the same value.
Caution: The power fuses on the amp are for protecting the amp against overdrive. To protect the vehicle’s
electrical system, an additional fuse is required within 18" of the battery on the 12V+ cable.

Thunder342 - 20A x 2
Thunder502 - 30A x 2
Thunder942 -150 Amps (not supplied)

2. Power Terminal – This is the main power input for the amplifier and must be connected directly to the
positive terminal of the car battery for the amplifier to operate properly. See the chart below for recom­mended cable sizes for each amplifier. Use caution when running this cable through the car. Try to avoid
the input RCA cables, antenna cabling, or other sensitive equipment as the large amount of current flowing
through this cable can induce noise into your system. It is also very important to have a tight connection to
ensure maximum performance.

Thunder342 – 10 Gauge
Thunder502 – 6 - 8 Gauge
Thunder942 – 1/0 Gauge

3. Ground Terminal – A good quality ground is required for your Thunder Amplifier to operate at peak
performance. A short length of cable the same gauge as your power cable should be used to attach the
ground terminal directly to the chassis of the car. Always scrape or sand any painted surfaces to expose
bare metal where the ground wire will attach.

4. Remote Terminal – All Thunder Amplifiers can be turned on by applying 12 volts to this terminal.
Typically this voltage is supplied by a wire from the source unit marked “remote” or “electric antenna”.

5. Speaker Terminals – As shown in the wiring diagrams, be sure to observe speaker polarity through
the system. Failing to wire the speakers in proper phase could result in a loss of bass response and/or poor
overall sound quality. Caution: Thunder amplifiers are not recommended for loads below 2 ohms stereo or 4
ohms bridged.

6. Power LED (top of heatsink) - A lighted LED indicates that power has been applied to the amplifier.
+12V from the battery to the +BATT terminal and +12V from a switched ignition or remote lead from a head
unit. An unlighted LED indicates power has been removed or the amplifier has overheated. In the case of
the overheat condition, the amplifier will turn back on after it cools down.

Output Panel Layout

❶

❺

❷❶❹❸

❺

❷

❹

❸

❷

❹

❸

❺

POWER AMPLIFIER OWNER’S MANUAL

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FELICITATIONS...

vous félicitant de votre achat d’un nouveau
amplificateur MTX Audio Thunder! MTX a été
depuis longtemps un leader dans l’industrie
d’enclos mobiles et speakers, et nous
sommes arrivés à un nouveau sommet avec le
développement des nouveaux amplificateurs
MTX Thunder. Vous n’auriez pas pu choisir
d’amplificateur plus fiable, plus puissant ou
meilleur. En effet ; nous garantissons pendant
trois ans chaque amplificateur Thunder s’il est
installé par un vendeur agréé (voir la
garantie).

Votre nouvel amplicateur MTX Thunder a été

conçu, construit et testé dans notre usine
électronique de dernier cri. Nous fabriquons
chaque amplificateur en employant la Technologie
Surface Mount le plus récent et intelligent.
Quelques advantages du nouveau dessin sont les
perfectionnements aux propriétés mécaniques et
électriques de l’amplificateur. Les mécanismes
SMT ont de substantiellement plus courtes
longueurs internes et externes. Cela réduit l’induc­tance et la capacitance égarées, qui résulte en une
reproduction musicale plus pure et plus exacte
avec considérablement moins d’intervention du
bruit. Le SMT mounter produit des cartes d’amplifi­cateur avec plus petits et plus légèrs composants
qui sont plus résistants aux vibrations inhérentes
dans l’environnement automobile.

Un mot au sujet d’évaluations de puissance. C’est
important de savoir comment elles s’y comparent.
MTX a choisi la méthode la plus honnête et la plus
conservatrice d’estimer les ampères. Nous vous
montrons la puissance RMS, aux 12,5 volts et la
puissance dynamique aux 14,4 volts. Cependant ;
nous allons au-delà l’appel de devoir. Nous testons
chaque amplificateur. Le technicien enregistre la
puissance de sortie ‘actuelle’, et puis il note ce
nombre sur votre Certificat de Performance Attesté.
L ’amplificateur doit satisfaire ou dépasser les spéci­fications d’évaluation avant d’être envoyé. Pas de
questions. Pas d’exceptions.

Nous voulons tout faire pour assurer que vous
obtenez la haute performance continue de votre
amplificateur MTX Thunder, donc nous vous recom­mandons de l’avoir installé professionellement par
votre vendeur agréé.

COMMENT UTILISER CE MANUEL

Si vous installez cet amplificateur vous-même, nous
vous recommandons de lire ce manuel de la pre­mière à la dernière page avant de l’installer.
Familiarisez-vous avec les caractéristiques et les
détails des panneaux entrée-sortie. Vérifiez que
vous avez tout l’équipement dont vous avez besoin.
Puis suivez les instructions d’installation point par
point qui se trouvent. Vous pouvez trouver des
échantillons des diagrammes d’installation sur le
Web à notre site :

mtx.com

Si vous avez des questions, écrivez ou

téléphonez-nous à :

MTX Audio

4545 E. Baseline Rd.

Phoenix, AZ 85042

602-438-4545

800-CALL MTX

[e-mail]

mtx.com

Introduction

FRANÇAIS

• Les amplificateurs Thunder sont couverts par un
ou plusieurs des brevets suivants aux États-Unis :
n° 5 598 325, n° 5 631 608, n° 5 783 970

• Mise sous tension/hors tension acoustiquement
transparente

• Réglage de sensibilité d’entrée

• Dispositif anti-choc de montage de carte

• Transformateur de forte puissance

• Technologie intelligente de montage en surface

• Barrettes de raccordement nickelées
de haute qualité

• Alimentation MLI brevetée à commutation
par MOSFET

• Circuit de protection à numérisation en temps réel

• Pieds Iso-Feet™ isolés en caoutchouc

• Filtre passe-haut stéréo 12 dB/octave, passe-bas
mono 24 dB/octave

• Conception de circuit compatible

• Sortie RCA tamponnée pour la configuration en
chaîne de plusieurs amplificateurs

• Sensibilités d’entrées gauche et droite réglables
individuellement

• Topologie discrète brevetée de circuit de haut­parleur 100 % classe A

• Conception brevetée à canal N pur

• Renforcement des basses Thunder EQ

• Sortie de filtre RCA de suivi

• Mise sous tension automatique Smart-Engage™
facilitant l’intégration avec les appareils sources
montés en usine lors de l’utilisation des entrées
haut-parleur (THUNDER342)

• Sortie de filtre RCA de suivi (THUNDER342)

Caractéristiques

Specifications

THUNDER342

• RMS Power measured at 12.5 Volts DC:
60 Watts x 2 into a 4 Ohm load with less than 0.1% Thd+N
120 Watts x 2 into a 2 Ohm load with less than 0.1% Thd+N
240 Watts bridged into a 4 Ohm load with less than 0.1% Thd+N

• Dynamic Power measured at 14.4 Volts DC:
85 Watts x 2 into a 4 Ohm load
170 Watts x 2 into a 2 Ohm load
340 Watts bridged into a 4 Ohm load

• Signal to Noise Ratio: ≥110dB A-Weighted

• Damping Factor: >200

• Frequency Response: 20Hz-20kHz ± 0.25dB

• Maximum Input: 8Vrms

• Thunder EQ: Variable Bass Boost (0-18dB) centered at 40Hz

• Crossover: Variable 40Hz to 200Hz, 12dB/Octave Stereo
High Pass, 24dB/Octave Mono Low Pass, or Full Range

• Dimensions: 10.7" x 9.75" x 2.1" (27.2cm x 24.8cm x 5.3cm)

THUNDER502

• RMS Power measured at 12.5 Volts DC:
90 Watts x 2 into a 4 Ohm load with less than 0.1% Thd+N
180 Watts x 2 into a 2 Ohm load with less than 0.1% Thd+N
360 Watts bridged into a 4 Ohm load with less than 0.1% Thd+N

• Dynamic Power measured at 14.4 Volts DC:
125 Watts x 2 into a 4 Ohm load
250 Watts x 2 into a 2 Ohm load
500 Watts bridged into a 4 Ohm load

• Signal to Noise Ratio: ≥110dB A-Weighted

• Damping Factor: >200

• Frequency Response: 20Hz-20kHz ± 0.25dB

• Maximum Input: 8Vrms

• Thunder EQ:Variable Bass Boost (0-18dB) centered at 40Hz

• Crossover: Variable 40Hz to 200Hz, 12dB/Octave Stereo
High Pass, 24dB/Octave Mono Low Pass, or Full Range

• Dimensions: 12.6" x 9.75" x 2.1" (32.1cm x 24.8cm x 5.3cm)

THUNDER942

• RMS Power measured at 12.5 Volts DC:
175 Watts x 2 into a 4 Ohm load with less than 0.1% Thd+N
350 Watts x 2 into a 2 Ohm load with less than 0.1% Thd+N
700 Watts bridged into a 4 Ohm load with less than 0.1% Thd+N

• Dynamic Power measured at 14.4 Volts DC:
235 Watts x 2 into a 4 Ohm load
470 Watts x 2 into a 2 Ohm load
940 Watts bridged into a 4 Ohm load

• Signal to Noise Ratio: ≥110dB A-Weighted

• Damping Factor: >200

• Frequency Response: 20Hz-20kHz ± 0.25dB

• Maximum Input: 8Vrms

• Thunder EQ: Variable Bass Boost (0-18dB) centered at 40Hz

• Crossover: Variable 40Hz to 200Hz, 12dB/Octave Stereo
High Pass, 24dB/Octave Mono Low Pass, or Full Range

• Dimensions: 17.8" x 9.75" x 2.1" (45.3cm x 24.8cm x 5.3cm)