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 perform-
ing amplifier. In fact, we back up every
Thunder amplifier with a three-year warranty
if installed by an authorized MTX Audio retail-
er (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 signifi-
cant improvements to the amplifier’s electrical and
mechanical properties. ISMT devices feature sub-
stantially 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 interfer-
ence. The ISMT mounter produces amplifier boards
with smaller and lighter components, which are
more resistant to vibrations inherent in the automo-
tive 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 per-
formance 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 rec-
ommend 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 instruc-
tions 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
technical@mtx.com
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:V ariable 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)