GPX2000.5 - Receiver Crunch - Free user manual and instructions

Product Type	5-Channel Car Amplifier
Brand	Crunch
Model	GPX2000.5
Power Supply	12 V (9-15 V), negative ground
Fuse	2 × 40 A
Dimensions (W × H × D)	254 × 46 × 390 mm
FRONT/REAR Speaker Impedance	2 Ω min (4 channels), 4 Ω min (bridged)
SUB Speaker Impedance	1 Ω minimum
FRONT/REAR High-Pass Filter	Adjustable (HPF)
SUB Low-Pass Filter	Adjustable (LPF)
SUB Subsonic Filter	Adjustable, 10 Hz minimum
SUB Bass Boost	0-12 dB, frequency 40-60 Hz
Remote Bass Level Control	Yes
Protection	Protection LED (overheating, short circuit)
Audio Inputs	RCA (FRONT, REAR, SUB)
Speaker Outputs	5 channels (FRONT L/R, REAR L/R, SUB)
Input Sensitivity	Adjustable (Gain)
Protection Circuit	Yes, automatic shutdown in case of fault

Frequently Asked Questions - GPX2000.5 Crunch

How to connect the Crunch GPX2000.5 amplifier?

First connect the GND terminal to the vehicle ground, then the +12V terminal to the battery via an inline fuse (cable gauge ≥10mm²). Next, connect the REM wire to the remote turn-on output of the head unit. Finally, connect the RCA cables and speakers to the corresponding outputs.

What is the output power of the amplifier?

The RMS output power is not specified in the manual. However, the 2x40A fuses indicate a maximum power of about 800W (at 12V). For exact values, refer to the technical specifications provided by the manufacturer.

How to adjust the gain (input sensitivity)?

Set the head unit volume to about 75% of its maximum. Turn the corresponding GAIN control (FRONT, REAR or SUB) until you get clear sound without distortion. A setting too high may damage the speakers.

What to do if the protection LED lights up red?

The red PROTECT LED indicates overheating or a short circuit. Check the speaker connections (impedance too low) and ensure the amplifier is well ventilated. Let it cool before restarting. If the problem persists, inspect the ground wiring and fuses.

How to connect a subwoofer in 5-channel mode?

Connect the FRONT and REAR outputs to satellite speakers (impedance ≥2Ω per channel) and the SUB output to the subwoofer (impedance ≥1Ω). Use the corresponding RCA inputs from the head unit. Set the filters: HPF for satellites (e.g., 125Hz) and LPF for the sub (e.g., 125Hz).

How to use the high-pass and low-pass filters?

The high-pass filter (HPF) for FRONT/REAR cuts low frequencies below the selected frequency, protecting small speakers. The low-pass filter (LPF) for SUB cuts high frequencies above the selected frequency, reserving bass for the subwoofer. Adjust according to the speakers and your preferences.

What is the minimum speaker impedance?

For FRONT and REAR channels in 4-channel mode, minimum impedance is 2 ohms per channel. In bridged mode, it is 4 ohms. For the SUB output, minimum impedance is 1 ohm. Do not go below to avoid damaging the amplifier.

How to install the amplifier in the car?

Choose a location with good airflow, ideally in the trunk. Mount the amplifier on a flat, stable surface. Keep power cables away from audio cables to avoid interference. Ensure the fuse and controls remain accessible.

How to use the remote bass level control?

Connect the supplied remote control cable to the REMOTE SUB connector on the amplifier (Fig.1.17). Place the remote within reach. Turn the knob to adjust the subwoofer bass level in real time, without affecting the other channels.

What to do if the amplifier does not turn on?

First check the inline fuse near the battery, as well as the amplifier's fuses (2x40A). Ensure the +12V terminal receives 9-16V and the REM terminal is powered (remote wire). Check the ground (GND) connection to a clean metal surface. If the POWER LED remains off, the problem is likely electrical.

USER MANUAL GPX2000.5 Crunch

Please read the user's manual carefully before the installation and the first operation of the amplifier.

SPECIFICATIONS

Output Power RMS FRONT & REAR Output Power RMS SUB

Output Power Max. FRONT & REAR Output Power Max. SUB

Loudspeaker impedance FRONT & REAR Loudspeaker impedance SUB

Frequency Response FRONT & REAR Frequency Response SUB

Total Harmonic Distortion FRONT & REAR Total Harmonic Distortion SUB

Signal-to-Noise Ratio

Input Sensitivity

Input Impedance

Highpass Filter FRONT & REAR

Lowpass Filter SUB

Subsonic Filter SUB

Bass Boost SUB

Operating Voltage

Fuse Rating

Dimensions (B x H x L)

All Specifications are subject to change

GPX2000.5

4 x 75/125 W @ 4/2 Ohms

1 x 200/350/500 W @ 4/2/1 Ohms

4 x 150/250 W @ 4/2 Ohm

1 x 400/700/1000 W @ 4/2/1 Ohms

2-8 Ohms

1-8 Ohms

10 Hz - 40 kHz (-3 dB)

10 Hz - 250 Hz (-3 dB)

< 0,2% (1 kHz)

< 0,2% (100 Hz)

90dB

0,4 - 6V

10 kOhms

32-2000Hz@12dB/Octave

32-300 Hz @ 12 dB/Octave

10-60Hz@12dB/Octave

0-12dB@40-60Hz

+12 V (9 - 15 V), negative ground

2 × 40A

254× 46× 360 / 390mm

IMPORTANT NOTES PRIOR TO INSTALLATION

• This device is only suited for a 12 volt system with negative ground.
• The radiated heat while operation requires sufficient air circulation at the place of installation. It is very important that the heat sink fins do not have contact with any metal parts or any surfaces which could impair air circulation. The amplifier may not be installed in small closed location or spaces without air circulation (e.g. spare wheel recess or below the vehicle carpeting). We recommend the installation in the vehicle's trunk. Ensure sufficient protection against vibrations, dust and dirt.
• Ensure that the input and output cables are sufficiently separated from the power supply cables. Otherwise interferences may occur.
• Ensure the accessibility of the fuse and the operating elements after installation.
• The reliability and performance of the amplifier depends on the quality of installation. Preferably consult an expert to install the system, particularly if you want to install several loudspeakers.

IMPORTANT!

Always observe the correct polarity of all connections!

INTERCONNECTION

POWER SUPPLY AND TURN-ON-CONNECTION

ATTENTION: Before you start with the installation, disconnect the ground connection from the vehicle's battery in order to prevent short circuits.

The power wiring which is usually installed in on-board car networks is not sufficient for a power amplifier's demands. Make sure that the power wires to GND and to the +12V terminal has been sufficiently specified. A cable cross-section of at least 10mm^2 must be used to connect the battery to the amplifier's terminals.

First connect the GND terminal of the amplifier to an appropriate ground connection at the chassis. To ensure a good connection, residue dirt and dust from the connection point. A loose connection may cause malfunctions or interferences noise and distortion.

Then connect the +12V terminal of the amplifier with the battery by using an appropriate cable including an in-line fuse. This fuse should be located very close to the battery; for safety reasons not more than 30~cm away. Only insert the fuse when the installation, including the connection of the loudspeakers, has been accomplished.

Then connect the remote turn-on-wire from the head unit with the amplifier's REM terminal. A cable with a cross-section of 0.5mm^2 is adequate.

LOUDSPEAKER CONNECTIONS

• FRONT & REAR: The impedance must not be lower than 2 ohms for each speaker. In bridging mode (two amplifier outputs combined) the impedance must not be lower than 4 ohms for the bridged output.
• SUB: The impedance must not be lower than 1 ohm.
• Never connect loudspeaker cables with the ground of the chassis or the +12V supply voltage.

If the amplifier is operated with a too low impedance or incorrectly used, the entire sound system may be damaged. This means a warranty void in such cases.

AUDIO SIGNAL CABLES

When installing the audio cables between the RCA outputs of the head unit and the RCA inputs of the amplifier, the audio and power supply cables should, if possible, not be routed along the same side of the vehicle. We recommend a separated installation, e.g. routing the power cable through the cable channel on the left side and the audio cables through the cable channel of the vehicle on the right side or vice versa. This prevents interferences due to crosstalk into the audio signal.

OPERATING ELEMENTS

INPUT SENSITIVITY (FRONT, REAR & SUB)

Turn the GAIN (Fig. 1.3, 1.6 or 1.16) controller of the amplifier to the MIN position. Then turn the volume controller of the head unit to 80 - 90% of its full setting. Now turn GAIN clockwise until you hear some distortion. Then turn back the GAIN slightly until you hear a cleaner sound.

VARIABLE HIGH PASS FILTER (FRONT & REAR)

Set the desired crossover frequency on the HPF controller (Fig. 1.3 or 1.8). Thus to that only the frequencies above the chosen crossover frequency will be amplified. This effectively minimizes distortions and overloads at lower frequencies. A good point to start is at 125Hz

VARIABLE LOW PASS FILTER (SUB)

Set the desired crossover frequency by using the controller (Fig. 1.14). Thus to that only the frequencies below the chosen crossover frequency will be amplified and the subwoofer plays more precise and efficient. A good point to start is at 125Hz

VARIABLE BASS BOOST (SUB)

With the controller BASS BOOST (Fig. 1.13) you are able to adjust the bass level from 0 - 12 dB. Use the controller EQ (Fig. 1.12) to set the frequency of the boost between 40 and 60Hz .

Attention: Use the controller BASS BOOST wisely!

VARIABLE SUBSONIC FILTER (SUB)

With the SUBSONIC controller (Fig. 1.15) you can adjust the lower crossover frequency, to filter the very low frequencies to relieve the subwoofer or to generate a bandpass signal. If you don't want to use this function, turn the controller (Fig. 1.15) to the very left to the 10Hz position.

NOTE: The adjusted value of the SUBSONIC (Fig. 1.15) should not be higher than the adjusted value of the LPF controller (Fig. 1.14). Otherwise no sound will be audible.

BASS LEVEL REMOTE CONTROLLER (SUB)

With the included bass level cable remote controller (Fig. 1.17) you are able to adjust the bass level e.g. out of the driver's seat.

PROTECTION CIRCUIT

The POWER LED (Fig. 1.9) lights up green, if the amplifier is in operation.

The PROTECTION LED (Fig. 1.9) lights up red, when the amplifier is overheated, or a short circuit occurs resp. a too low impedance load is connected to the speaker outputs. If this events, the internal built-in protection circuit shuts down the amplifier automatically. The amplifier should work again properly after you have solved the problems.

FIGURES (P. 28-31)

CONNECTIONS AND CONTROLLER (FIG. 1)

(1) Audio signal inputs (FRONT)
(2) Audio signal inputs (REAR)
(3) High pass filter controller (FRONT)
(4) Selector HPF (High pass filter) - FULL (FRONT)
(5) Gain controller (FRONT)
(6) Gain controller (REAR)
(7) Selector HPF (High pass filter) - FULL (REAR)
(8) High pass filter controller (REAR)
(9) Power-/Protection-LED
(10) Audio signal inputs (SUB)
(11) Input mode (please refer to page 31)
(12) Frequency controller for Bass Boost (SUB)
(13) Bass Boost controller (SUB)
(14) Low pass filter controller (SUB)
(15) Subsonic filter controller (SUB)
(16) Gain controller (SUB)
(17) Connector for the included bass level remote controller

POWER SUPPLY AND TURN ON CONNECTION (FIG. 2)

(1) GND terminal for the ground
(2) REM terminal for the turn on connection
(3) +12V terminal for the positive-connection of the battery
(4) Fuses
(5) Vehicle's battery
(6) Inline fuse (not included in the scope of delivery)
(7) Turn on wire from the head unit or the electrical antenna

5-CHANNEL OPERATION STEREO & MONO (FIG. 3)

If you want to run the amplifier with the 5 line output channels to drive two pairs of loudspeakers and a subwoofer, connect the following setup:

(1) To the head unit, line output left FRONT
(2) To the head unit, line output right FRONT
(3) To the head unit, line output left REAR
(4) To the head unit, line output right REAR
(5) Bass level remote controller
(6) To the head unit, left subwoofer output SUB
(7) To the head unit, right subwoofer output SUB
(8) Loudspeaker left FRONT
(9) Loudspeaker right FRONT
(10) Loudspeaker left REAR
(11) Loudspeaker right REAR
(12) Subwoofer

3-CHANNEL OPERATION STEREO & MONO (FIG. 4)

If you want to run the amplifier with the 2 line output channels to drive a bridged pair of loudspeakers and a subwoofer, connect the following setup:

(1) To the head unit, line output left FRONT
(2) To the head unit, line output right FRONT
(3) Bass level remote controller
(4) Loudspeaker left FRONT on RL - and RR +
(5) Loudspeaker right FRONT on FL - and FR +
(6) Subwoofer

TROUBLESHOOTING

If you are having problems after installation follow the Troubleshooting procedures below.

Procedure 1:

Check Amplifier for proper connections.

POWER LED lights up green. In this case skip to Step 3, if not continue.

1. Check in-line fuse on battery positive cable. Replace if necessary.
2. Check fuse(s) on amplifier. Replace if necessary.
3. Verify that Ground connection is connected to clean metal on the vehicle's chassis. Repair/replace if necessary.
4. Verify there is 9 to 16 Volts present at the positive battery and remote turn-on cable. Verify quality connections for both cables at amplifier, stereo, and battery/fuse holder. Repair/replace if necessary.

Procedure 2:

PROTECTION LED lights up red.

1. If the LED lights up red it is a sign of a possible short in the speaker connections. Check for proper speaker connections and use an ohm meter to check for possible shorts in the speaker wiring. Too low speaker impedance may also cause PROTECTION to light. This can also be a sign of driving the amplifier at very high power gains without adequate airflow around the amplifier. Shut off the system and allow amplifier to cool. Check that the vehicle charging system is maintaining proper voltage. If the previous items do not solve the problem, a fault may be in the amplifier. In this case you should contact your dealer.

Procedure 3:

Check Amplifier for audio output.

1. Verify good RCA input connections at stereo and amplifier. Check entire length of cables for kinks, splices, etc.

Test RCA inputs for AC volts with stereo on. Repair/replace if necessary.

Procedure 4:

Check Amplifier for a popping noise while turning on.

1. Disconnect input signal to amplifier and turn amplifier on and off.
2. If the noise is eliminated, connect the REMOTE lead of amplifier to source unit with a delay turn-on module.

Procedure 5:

Check Amplifier if you experience excess Engine Noise.
1. Route all signal carrying wires (RCA, Speaker cables) away from power and ground wires.
OR
2. Bypass any and all electrical components between the head unit and the amplifier(s). Connect stere directly to input of amplifier. If noise goes away the unit being bypassed is the cause of the noise.
OR
3. Remove existing ground wires for all electrical components. Reground wires to different locations.
Verify that grounding location is clean, shiny metal free of paint, rust etc.
OR
4. Add secondary ground cable from negative battery terminal to the chassis metal or engine block of vehicle.

Dimensions (L x H x P)

4 x 75/125 W @ 4/2 Ohm

1 x 200/350/500 W @ 4/2/1 Ohm

4 x 150/250 W @ 4/2 Ohm

1 x 400/700/1000 W @ 4/2/1 Ohm

2-8 Ohm

1-8 Ohm

10 Hz - 40 kHz (-3 dB)

10 Hz - 250 Hz (-3 dB)

< 0,2% (1 kHz)

< 0,2% (100 Hz)

90dB

0,4-6V

10 kOhm

32-2000Hz@12dB/Octave

32-300 Hz @ 12 dB/Octave

10-60Hz@12dB/Octave

0-12dB @ 40-60 Hz

CONTROLLO REMOTO DAL LIVELLO DEI BASSI (SUB)

4 x 75/125 W @ 4/2 Ohmios
1 x 200/350/500 W @ 4/2/1 Ohmios

4 x 150/250 W @ 4/2 Ohm
1 x 400/700/1000 W @ 4/2/1 Ohmios

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