GTA 250 - Audio Amplifier BLAUPUNKT - Free user manual and instructions

Product type	2-channel car audio amplifier
Dimensions (W x H x D)	242 x 49.5 x 232 mm
Power supply	12 V DC (vehicle battery)
Max power (stereo, 4 Ω)	2 x 100 W
Max power (stereo, 2 Ω)	2 x 160 W
Max power (mono, 4 Ω)	1 x 400 W
RMS power (stereo, 4 Ω)	2 x 50 W
RMS power (stereo, 2 Ω)	2 x 80 W
RMS power (mono, 4 Ω)	1 x 160 W
Frequency response	10 Hz - 30 000 Hz
Signal-to-noise ratio	> 90 dB
Stability	2 Ω
Input sensitivity	0.1 - 8 V
Low-pass filter	40 - 450 Hz
High-pass filter	65 - 450 Hz
Bass boost	0 - 18 dB
Inputs	RCA input
Speaker outputs	Screw terminals
Operating modes	Stereo or Mono (bridged)
Recommended cable gauge	≥ 6 mm²
Built-in fuses	Yes (protects the amplifier)
Recommended installation	Under seat or in trunk, dry and ventilated area
Maintenance and cleaning	Clean with a dry soft cloth. Do not use liquids.
Safety	Disconnect battery before installation. Do not bypass fuses.
Spare parts and repairability	Contact Blaupunkt after-sales service or hotline.

Frequently Asked Questions - GTA 250 BLAUPUNKT

How to connect the amplifier to the car radio?

Use a Cinch (RCA) cable to connect the preamp output of the car radio to the Cinch input of the amplifier. If the car radio has a Blaupunkt ISO connector, use an ISO-Cinch adapter (ref. 7 607 893 093 or 7 607 855 094).

What type of fuse to use for the power supply?

The power cable must be protected by a fuse placed within 30 cm of the battery. The built-in fuse in the amplifier protects only the amplifier. Never replace with a higher-rated fuse.

How to adjust the gain (input sensitivity)?

Turn the gain control clockwise to increase sensitivity (0.1 V to 8 V). This is not a volume: too high gain can cause distortion. Adjust it according to the output voltage of the car radio.

What does the red POWER/PROTECTION LED mean?

The red LED indicates that the output stage is electronically disconnected due to a fault (short circuit, overheating, too low impedance). Check connections and cooling.

Can I connect 4-ohm speakers?

Yes, the amplifier is stable at 2 ohms. You can connect 4-ohm speakers in stereo (2 x 100 W max) or in bridged mono mode (1 x 400 W max at 4 ohms).

How to configure the low-pass filter for a subwoofer?

Set the switch to Low-Pass and adjust the cutoff frequency between 40 and 450 Hz. For a subwoofer, a typical value is 80-120 Hz. Optionally enable Bass Boost (0 to +18 dB).

What power cable gauge is recommended?

Use a cable of minimum 6 mm² for the +12V and ground connections. Larger diameter cables may be necessary if the distance is long.

Where to install the amplifier in the car?

Install it in a dry and well-ventilated place, for example under a seat or in the trunk. Secure it firmly to prevent movement in case of an accident. Avoid areas exposed to moisture.

How to switch to mono (bridged) mode?

Connect the speaker between the positive terminals of both channels (CH1+ and CH2+) and the negative terminals (CH1- and CH2-). Ensure the total impedance is at least 4 ohms. Mono mode allows powering a subwoofer with a maximum power of 400 W.

What to do in case of overheating or unexpected shutdown?

Check that ventilation is not obstructed and that the speaker impedance is not too low (e.g., below 2 ohms in stereo, or 4 ohms in mono). Reduce volume or gain. If the problem persists, contact Blaupunkt after-sales service.

USER MANUAL GTA 250 BLAUPUNKT

Congratulations on your purchase of a high-quality GTA power amplifier. By selecting the GTA 250 you have chosen a product which delivers superlative reproduction quality. Whether you are upgrading an existing system or using the GTA power amplifier in a new system, you are certain to notice immediate performance benefits!

The Blaupunkt editors are constantly working on making the operating instructions clearer and easier to understand. However, if you still have any questions on how to operate the equipment, please contact your dealer or the telephone hotline for your country. You will find the hotline telephone numbers printed at the back of this booklet.

We provide a manufacturer guarantee for our products bought within the European Union. You can view the guarantee conditions at www.blaupunkt.de or ask for them directly at:

Blaupunkt GmbH

Hotline

Robert Bosch Str. 200

D-31139 Hildesheim

Germany

Recommendation:

A power amplifier's performance is only as good as its installation. Proper installation will maximise the overall performance of your audio system. We recommend that you have our product installed professionally. Should you decide to install the amplifier yourself, however, please read through these instructions carefully, and take your time over the installation.

Finally, a word about your health: please bear in mind when playing music in your car that sustained sound levels above 100 dB can damage your hearing and may even result in total hearing loss. Modern high-performance systems and high-quality loudspeaker configurations are quite capable of generating noise levels above 130 dB

Safety precautions Instructions for installation and connection

Fit a fuse in the amplifier power line no more than 30~cm from the vehicle battery, in order to protect the battery in the event of a short-circuit between it and the power amplifier. The amplifier's own fuse protects the amplifier itself, but not the car battery. Disconnect the negative terminal of the battery before carrying out installation and connection work.

Observe the vehicle manufacturer's safety instructions (regarding airbags, alarm systems, trip computers, vehicle immobilisers).

The final stage must be installed professionally for reasons of safety. The mounting surface must be suitable for the screws provided, and must provide firm support.

When drilling holes, take care to avoid damage to vehicle components (battery, cables, fuse boxes).

Fit the amplifier in a suitable location, e.g. beneath the seats or in the trunk (Fig. 1). The mounting location must also be dry, and provide sufficient ventilation for cooling of the amplifier. Use cable grommets when passing cables through holes with sharp edges. Use loudspeakers with an impedance of 2 to 4 (see table or installation drawing). Observe the max. power handling specifications (music output). Do not connect the loudspeakers to ground; only use the terminals provided. The cross-section of the positive and negative cable must be at least 6mm^2 .

GTA 250 amplifier

The amplifier is suitable for connection to car radios with Cinch connector. Use the Blaupunkt ISO Cinch adapter to connect the amplifier to car radios with ISO connector (7 607 893 093/ 7 607 855 094).

Applications and loudspeaker connection

Stereo-Mode Max Power	2 x 100 Watt / 4 Ω	Fig. 4, 4a
Mono-Mode Max Power	1 x 400 Watt / 4 Ω	Fig. 5
Stereo-Mode Max Power	2 x 160 Watt / 2 Ω	Fig. 4, 4a
Stereo-Mode RMS Power	2 x 50 Watt / 4 Ω	Fig. 4, 4a
Mono-Mode RMS Power	1 x 160 Watt / 4 Ω	Fig. 5
Stereo-Mode RMS Power	2 x 80 Watt / 2 Ω	Fig. 4, 4a
Frequency response	10 Hz - 30.000 Hz
Signal-to-noise ratio	>90 dB
Stability	2 Ω
Input-sensitivity	0,1 - 8 V
Low-pass filter	40 - 450 Hz
High-pass filter	65 - 450 Hz
Bass Boost	0-18 dB
Dimensions W x H x D (mm)	242 x 49,5 x 232

Positive/negative connection

We recommend a cable cross-section of not less than 6mm^2 . Run a standard commercial positive cable to the battery and connect to the fuse holder. Use cable grommets when passing cables through holes with sharp edges. Bolt a standard commercial negative cable to a ground point free of induced noise (car body bolt, body panel) - not to the negative battery pole. Clean the contact surface of the ground point down to bare metal and coat with antiseize graphite petroleum.

Integral fuses

The integral fuses within the amplifier protect the final stage and the entire electrical system in the event of a fault. Never bridge fuses or replace fuses with a higher current rating.

Example connections

Power supply connection fig. 2.

Connection of car radio with cinch output fig.3.

Loudspeaker connections fig. 4.

Connect remote amplifier connection to switchable +12V power source.

This enables the amplifier to be switched on and off with the radio's On/Off switch.

Level control

The Level control enables the input sensitivity of the final stage to be matched to the output voltage of your car radio preamp output.

The range of adjustment extends from 0.1 V to 8 V.

Adjust the input sensitivity in accordance with the manufacturer's specifications when connecting the amplifier to other radios.

Important:

Turning the Level control clockwise increases the input sensitivity of the amplifier, and thereby also the volume. The Level control is however not a volume control; an increase in volume is not achieved in the maximum position, even if this subjectively appears to be the case. The system merely increases the volume more quickly when the volume is turned up on the radio.

Loudspeaker connections

(If the amplifier is to be connected in a bridged mode, proceed with the section "Bridged loudspeaker connections".)

As with any audio component, connection of the amplifier and speakers with the correct polarity is essential for good bass reproduction. Ensure therefore when connecting that the positive (+) amplifier terminal is connected to the positive (+) loudspeaker terminal. The same applies to the negative (-) terminals. The left-hand amplifier chan

nel must also be connected to the left-hand loudspeaker and the right-hand amplifier channel to the right-hand loudspeaker.

Bridged loudspeaker connections

The GTA can also be bridged in a mono configuration. This enables you to use the amplifier for one or more subwoofer(s) or a mid-range speaker. In this configuration the amplifier sums the right-hand and left-hand channels, delivering a single channel (mono) output.

Note:

The amplifier can sum the right- and left-hand signal information only if both the right- and left-hand RCA connections have been made.

CAUTION:

The amplifier must be presented with a load of 4 Ohms or higher in bridged mode. A lower load will cause the amplifier to overheat or switch off. This can lead to permanent damage of the unit.

Adjustment of the type and range of the cross-over frequencies

The type of crossover (i.e. "low-pass" or "hipass") and the desired crossover frequency can be selected on the GTA 250. If, for example, you wish to drive a pair of subwoofoers, connect in accordance with the low-pass diagram (fig. 3). The crossover frequency is dependent upon the loud-speaker frequency range (consult the loudspeaker manufacturer's data for the recommended frequency range).

"High- Pass" frequency control

This control is active when the switch is in the "Hi-pass" position, and permits selection of the desired crossover frequency. Example: at a of 65Hz the loudspeaker has a frequency range of 65Hz to 30.000Hz .

"Low-pass" frequency control

This control is active when the switch is set to "Low-pass" and permits selection of the desired crossover frequency. Example: at a setting of 150Hz , the loudspeaker has a frequency range of 10Hz to 150Hz .

Bass boost

You can adjust the bass output of the amplifier using the bass boost control. The settings range covers 0 dB to +18 dB.

Operating indicator (POWER / PROTECTION)

Green lamp: Power amp on, regular operating condition

Red lamp: Power amp has been switched off electronically, due to a fault or failure.

FRANÇAIS

Introduction

"High pass"-frequentieregeling

This information is subject to change without notice!