TH904 - Car radio MTX Audio - Free user manual and instructions

Product type	4-channel audio amplifier
Brand	MTX Audio
Model	TH904
Class	AB
Channels	4
Dimensions (W x D x H)	383 x 213 x 52.5 mm
Power supply	12 V DC (vehicle battery)
Signal-to-noise ratio	>81 dB (1 watt)
Total harmonic distortion (THD)	≤0.25% (1 watt)
Frequency response	20 Hz – 20,000 Hz (±1 dB)
RCA input sensitivity	100 mV to 6 V
High-pass filter	40 Hz – 8,000 Hz, 12 dB/octave
Low-pass filter	40 Hz – 8,000 Hz, 12 dB/octave
Band-pass filter	Combination of HPF and LPF filters
Technologies	Smart Engage™, EAF, XTC, Pure N-Channel
Protections	Thermal, under/over voltage, short circuit
Inputs	Low-level (RCA) and high-level (with adapters)
Outputs	Speaker terminals, bridged mode (4 ohms min)
Fuse	Yes, replace with same value
Installation	Flat mounting, ensure ventilation
Maintenance	Clean with a soft dry cloth
Spare parts	Replacement fuses

Frequently Asked Questions - TH904 MTX Audio

How to properly adjust the amplifier gain?

Turn the Gain potentiometer to minimum (counterclockwise). Increase the source volume to 3/4 of its maximum, then gradually increase the Gain until you hear distortion. Slightly decrease the Gain to obtain clear sound.

What to do if the Power LED does not light up?

Check that the Remote cable receives +12V and that the +BATT cable is connected to the battery. Check the ground and the fuse condition. Replace the fuse if necessary with one of the same value.

Why does the amplifier go into thermal protection?

The amplifier protects its components when the internal temperature exceeds 100°C. Ensure that ventilation is adequate and that the amp is not obstructed. Reduce the volume or gain level if overheating persists.

How to use the band-pass filter?

Activate both the High-Pass (HPF) and Low-Pass (LPF) switches. Adjust the cutoff frequencies with the corresponding potentiometers to define the desired frequency range.

Can I use the amplifier with a source without RCA outputs?

Yes, thanks to Smart Engage™ technology. Use the supplied high-level adapters: connect the speaker cables from the source to the adapters, then connect these adapters to the RCA inputs of the amplifier.

How to wire the amplifier in bridged mode?

Use only the + terminal of the left channel and the - terminal of the right channel. Connect a single speaker or subwoofer. Observe a minimum impedance of 4 ohms in bridged mode.

What to do in case of distorted sound?

Check that the source volume is not too high and that the Gain setting is not excessive. Reduce the Gain and lower the source volume to restore clear sound.

Why is the bass weak?

Check that the speakers are wired respecting phase (+ to +, - to -). Phase inversion can cancel bass frequencies. Use MTX subwoofers for optimal performance.

What power cable gauge is recommended?

MTX recommends a cable with a cross-section of 21 mm² for power and ground. Use the same gauge for both. The power cable must be protected by a fuse within 20 cm of the battery.

How to install the amplifier correctly?

Choose a flat location with good air circulation. Secure the amp with screws. First connect the ground (GND) to bare metal, then the power (+BATT) to the battery via a fuse, the Remote wire, and finally the audio inputs/outputs.

USER MANUAL TH904 MTX Audio

4 Channel Class-AB Power Amplifier

600W RMS

Designed by MTX in Phoenix, USA

www.mtx.eu.com

www.mtx.com

Introduction

Thank you for purchasing an MTX Audio Hi-Performance amplifier. Proper installation matched with MTX speakers and subwoofers provide superior sound and performance for endless hours of waking the neighbors, slam-min' your friends or flat out stomping wanna-be players. Congrats and enjoy the ultimate audio experience with MTX!

Specifications :

• 4-Channel Class-AB amplifier
• CEA2006 certified Power Output :

- 150 watts RMS x 4-channels at 2 ohm and THD+N ≤1%

- 90 watts RMS x 4-channels at 4 ohm and THD+N ≤1%

- 300 watts RMS x 2-channels at 4 ohm and THD+N ≤1%

• Crossover :

• High pass 12dB/oct variable from 40Hz to 8000Hz
• Low pass 12dB/oct variable from 40Hz to 8000Hz
• Band pass 12dB/oct variable from 40Hz to 8000Hz
  • Signal-to-Noise Ratio (1 watt) : > 81dB
• THD+Noise (Distortion) (1 watt): ≤ 0,25%
  • Frequency Response (±1dB): 20Hz-20000Hz
  • Maximum Input Signal : 6V
  • Maximum Sensitivity : 100mV
  • Dimensions : 383mm x 213mm x 52,5mm
  • High level inputs with Smart Engage Technology

Features :

• XTC - (Xtant Technology Cooling) - A regulated thermal intercooler, injecting cool air through internal heat sinks. Fan speed is load dependent and continuously variable, sampling the temperature of the heat sink and transformers for maximum reliability. Intercooler exhaust is strategically placed to chill transformers and maintain exceptional performance at any volume level. (Cool eh ? An Amp with an Intercooler ! )
• Pure N-Channel Design - Patent N°: US05631608 and N°: US05783970 - MTX amplifiers incorporate N-Channel MOSFETs on both the positive and negative circuits of the output stage (PURE N-Channel Design). No additional circuits are needed to compensate for inefficient designs like P-Channel MOSFETs. Both the positive and negative circuits have equal usable power ratings. Genuine Genius...Yea we know...
• EAF Technology (Efficient Auto Former) - Patent N°: US05598325 - Our Transformers are "Auto Formers" which allows us to use smaller magnetics (-30% to -50%) yielding increased efficiency. Turn ratios are improved due to series connections between the primary and secondary taps meaning MORE Power!
• Smart Engage™ Technology - Patent N°: US06556683 - The amp switches on and off automatically when connected with high level inputs. No need for a remote turn on wire from under the dashboard. No need to remove the head unit. Thanks MTX!
• Bi-Level Inputs - High level inputs (Speaker cables) and line level inputs (RCA) utilize the same RCA type input connections on the amp.

Control Panel (Top)

Connectors Panel (Side)

Control Panel :

Gain Control - The gain control matches the input sensitivity of the amplifier to the source unit being used. The operating range varies from 100mv to 6V.

Adjusting the gain

1. Turn the gain control on the amplifier all the way down (counter clockwise).
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. The amplifier is now calibrated to the output of the source unit.

2 Low Pass X-Over Switch - Turns the active low pass (LP) x-over on and off. When engaged (in) the x-over is "ON", when disengaged (out) the x-over is "OFF"
3 Low Pass X-Over Frequency Control - Used to select the desired low-pass (LP) x-over frequency. The frequency is adjustable from 40Hz to 8000Hz.
4 High Pass X-Over Switch - Used to turn on the active high-pass (HP) x-over on and off. When engaged (in) the x-over is "ON", when disengaged (out) the x-over is "OFF".
5 High Pass X-Over Frequency Control - Used to select the desired high-pass (HP) x-over frequency. The frequency is adjustable from 40Hz to 8000Hz..
2 4 Band Pass X-Over: To use, turn "ON" the HP and LP x-overs at the same time, creating a band-pass x-over for kick woofers or midranges. You can tune the filter with frequency controls (3) and (5).

Important Notice: When both x-overs are turned "OFF", the pre-amp section is in "Direct" mode providing the best possible sound quality.

6 Power On LED - The LED illuminates red when the amp is switched on. For Short or Thermal protection, see points 9 and 10

Connectors panel :

7 RCA Inputs - These RCA inputs are used with source units that have RCA or Line level outputs. (Source units need a minimum level of 100mV output for proper operation of the amplifier).

MTX recommends only high quality twisted pair cables (such as StreetWires) to decrease the possibility of radiated noise entering the system.

High Level Inputs :

MTX amplifiers allow high level inputs through RCA type input connections. Simply connect the head unit speaker leads to the provided adapters.

8 Speaker Terminals - Connect speakers to these terminals. Observe speaker polarity throughout the system. Improper phase can result in loss of bass response and/or poor overall sound quality.

Bridge Mode:

When bridging the amplifier, use the left positive terminal and the right negative terminal only. Warning : do not bridge the amplifier with an impedance lower than 4 ohm.

9 Thermal Protection - This LED illuminates red when the amp reaches 100°C. The LED also turns red when the power supply goes below 9V or over 16.2V.

10 Short Circuit Protection - This LED will flash yellow when the speaker outputs will short circuit. Without signal, this LED can remain yellow when the speaker outputs are short circuited.

11 Fuses - When fuses blow, replace them with the same value. Never use a higher rated fuse!

12 (+12) Power Terminal - This is the main power input for the amplifier and must be connected directly to the positive terminal of the vehicles battery for proper operation. Use caution when installing (+12) power cable in the vehicle. Avoid running this cable parallel with RCA cables, antennas, or other sensitive equipment due to massive currents that can induce noise into the audio system. It is also very important to have a tight, secure connection for maximum performance. MTX recommends using 21mm ^2 power wire with the MTX TH904 amplifier.

13 Remote Terminal – The amplifier 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 "power antenna".

14 Ground Terminal – A proper ground is required for your amplifier to operate at peak performance. A short ground cable the same diameter as the power cable should be used to attach the ground terminal directly to the chassis of the vehicle. Always remove paint, dirt or debris to expose bare metal where the ground will be attached.

15 Input Switch: If the head unit is equipped with 4 RCA outputs (2 front and 2 rear), use the 4ch mode and connect the 4 RCA outputs to the 4 RCA inputs on the amp. If only 2 RCA outputs are available from the head unit, use the 2ch mode to feed the entire amp.

Installation & Mounting

MTX recommends your new Thunder amplifier be installed by an Authorized MTX retailer. Any deviation from specified installation instructions can cause serious damage to the amplifier, speakers and/or vehicles electrical system. Damage caused from improper installation is NOT covered under warranty. Please verify all connections prior to system turn on!

1. Disconnect the vehicle's negative battery cable.

2. Determine the mounting place for your MTX THUNDER amplifier. Keep in mind there should be sufficient air flow for proper cooling. Mark the mounting holes from the amplifier to be drilled. Before drilling make sure all vehicle wires, gas lines, brake lines and gas tank are clear and will not interfere with installation. Drill the desired holes and mount the MTX THUNDER amplifier.

3. Install a positive (+) power cable from the vehicle's battery through the firewall using a grommet or firewall bushing to avoid cable damage from sharp edges of the firewall. Run the cable through the interior of the vehicle and connect it to the amplifier's +BATT terminal. Do Not connect to the battery at this time.

Note: Use only proper gauge wire for both positive and negative connections.

1. Install a circuit breaker or fuse within 20cm of the battery. This effectively lowers the risk of severe damage to you or your vehicle in case of a short circuit or accident. Make sure the circuitbreaker is switched off or the fuse is taken out of the fuse holder until all connections are made. Now connect your positive power cable to the positive battery terminal of the battery.

2. Grounding - Locate a proper ground point on the vehicle's chassis and remove all paint, dirt or debris to reveal a bare metal surface. Attach the ground wire to that contact point. Connect the opposite end of the ground wire to the GND terminal on the MTX THUNDER amplifier.

3. Connect a Remote Turn-on wire from the source unit to the MTX THUNDER amplifier's Remote terminal. If the source unit does not have a dedicated Remote Turn-on lead, you may connect to the source unit's Power Antenna lead.

4. Connect RCA cables from the source unit to the MTX THUNDER amplifier's RCA Bi-level inputs. Both low and high level signals can be used. Run all signal cables away from vehicle wiring, computers and power cables. If cables must be crossed do so at a 90° angle. Use only high quality twisted pair interconnect cables to decrease radiated noise from entering the system.

- Using RCA Connections: Simply attach a signal cable from source units RCA outputs to the amp's RCA inputs. This provides input signal to the amp.

- Using Speaker Level Connections: If the source unit does not have RCA outputs, high level signals can be used by taking the supplied high level RCA adapter and connecting it to the vehicle's rear speaker wiring. Connect the left negative speaker wire to the green and black striped wire on the high level RCA adapter. Connect the left positive speaker wire to the solid green wire. Do the same for the right speaker connection using the purple wire. Now plug the RCA connectors into the amp's inputs.

1. Connect your speakers to your MTX THUNDER amplifier's speaker terminals using the right gauge speaker wire. Both channels bridged can drive a 4 ohm minimum load for max power.

2. Double check all previous installation steps, in particular, wiring and component connections. Once verified, reconnect the vehicle's negative battery cable, turn the circuit breaker on or place the fuse in the fuse holder.

Note : Gain Levels on the amplifier should be turned all the way down (counter clockwise) before proceeding with adjustments.

Troubleshooting

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

Power LED on, no output Volume on source unit off Increase volume on source unit

Speaker connections not made Make speaker connections

Gain control on amplifier off

Signal processing units off

All speakers blown

Output distorted

Amplifier gain set too high

Balance reversed

RCA inputs reversed

Bass is weak

Not using MTX woofers

Blowing fuses

Turn up gain

Apply power to signal processor

Replace speakers

Head unit volume set too high Lower head unit volume

Lower amplifier gain

Speakers wired L + R reversed

Reverse RCA input

Speakers wired out of phase

Buy MTX woofers

Excessive output levels

Wire speakers with correct orientation

Wire speakers with correct phase

Lower the volume

Amplifier defective Return for service

Introduction :

• 4 x 150 watts RMS @ 2 ohms et THD+N ≤1%
• 4 x 90 watts RMS @ 4 ohms et THD+N ≤1%
• 2 x 300 watts RMS ponté @ 4 ohms et THD+N ≤1%

• Filtre actif :

PROBLÈMES CAUSES SOLUTIONS

MTX woofers no son usados

Compra woofers MTX

Fusibles dañados

- Smart Engage™ Technology - Brevetto N°: US06556683 - The amp switches on and off automatically when connected with high level inputs. No need for a remote turn on wire from under the dashboard. No need to remove the head unit. Thanks MTX!

- 150 watts RMS x 4-canal a 2 ohm e THD+N ≤1%

- 90 watts RMS x 4-canal a 4 ohm e THD+N ≤1%

6 Power On LED - The LED illuminates red when the amp is switched on. For Short or Thermal protection, see points 9 and 10

Mode em ponte :

Não usando woofers MTX Adquira woofers MTX

Warning : Never adjust the gain control without a subwoofer connected.

This will damage the amp...

MTX is a proud member of Mitek Corp high quality consumer audio product lines.

MiTek

MTX®

AUDIO

Coustic®

xtant

STREETWIRES®

Designed and Engineered by Mitek in Phoenix - AZ, USA.

© 2008 Mitek. All rights reserved.

MTX, COUSTIC, XTANT, STREETWIRES and THUNDER are registered trademarks of Mitek.

Due to continual product development, all specifications are subject to change without notice

MTX Audio,

4545 East Baseline Rd.

Phoenix, AZ 85042

USA