GZTA 4125X-B - Receiver Ground Zero - Free user manual and instructions

Product Type	4-Channel Class A/B Amplifier
RMS Power @ 4 Ω (1% THD+N)	4 x 90 W
RMS Power @ 2 Ω (1% THD+N)	4 x 130 W
RMS Power Bridged @ 4 Ω (1% THD+N)	2 x 260 W
RMS Power Bridged @ 4 Ω (10% THD+N)	2 x 320 W
Frequency Response	5 Hz – 38 kHz (± 1 dB)
Total Harmonic Distortion (THD+N)	< 0.02%
Damping Factor	> 100
Input Sensitivity	500 mV – 9 V (± 5%)
High Pass Filter	5 Hz – 500 Hz (12 dB/oct)
Low Pass Filter	40 Hz – 4000 Hz (12 dB/oct)
Bass Boost	0 to +12 dB at 45 Hz
Input Type	2x Stereo RCA
Recommended Speaker Wire	≥ 2.5 mm² / 14 AWG
Recommended Power Wire	≥ 20 mm² / 4 AWG
Fuse Rating	2 x 35A
Dimensions (W x H x L)	230 x 53 x 396 mm (9.06 x 2.09 x 15.59 in)
Protection Circuits	Thermal, Short Circuit, Overload, Turn-on Delay
Cooling	Heatsink, ensure adequate airflow
Mounting	Not on vibrating surfaces like subwoofer enclosures

Frequently Asked Questions - GZTA 4125X-B Ground Zero

What is the recommended power wire gauge for the GZTA 4125X-B?

The recommended power wire is at least 20 mm² / 4 AWG to handle the current requirement.

Can I bridge the amplifier channels?

Yes, the GZTA 4125X-B can be bridged. In bridged mode, the minimum load is 4 ohms and the amplifier delivers up to 2 x 260 W (1% THD+N) or 2 x 320 W (10% THD+N).

What is the function of the mode switch?

The mode switch selects the crossover mode: FULL for full-range, HIGH to filter low frequencies, and LOW (BP) to create a band-pass filter between 5 Hz and 4000 Hz.

How do I adjust the input sensitivity?

Use the sensitivity control (item 5 on the amplifier) to match the head unit's output voltage. The range is 500 mV to 9 V. Turn it fully counterclockwise then slowly increase while listening for distortion.

What does the PROTECT LED indicate?

If the PROTECT LED lights red, the amplifier has entered protection mode due to overheating, short circuit, or overload. Check connections and ensure proper ventilation.

What are the filter frequency ranges?

The high pass filter is adjustable from 5 Hz to 500 Hz and the low pass filter from 40 Hz to 4000 Hz, both with a slope of 12 dB/octave.

Do I need to disconnect the battery before installation?

It is recommended to disconnect the vehicle battery. However, note that disconnecting the battery in some modern vehicles may cause errors that require a service partner to clear. Consult your dealer first.

What is the minimum speaker impedance per channel?

In stereo mode, the minimum impedance is 2 ohms per channel. In bridged mode, the minimum is 4 ohms.

How should I mount the amplifier to avoid overheating?

Mount the amplifier on a flat, non-vibrating surface. Ensure at least 1 inch (2.5 cm) of clearance around the heatsink for airflow. Never cover the heatsink or mount it on a subwoofer enclosure.

What is the purpose of the bass boost control?

The bass boost control allows you to add up to +12 dB of boost centered at 45 Hz. Use it sparingly to avoid distortion.

USER MANUAL GZTA 4125X-B Ground Zero

GROUND ZERO products are engineered in Germany GROUND ZERO – international sponsor

Ground Zero GmbH

Erlenweg 25, 85658 Egmating, Germany

Tel. [phone] Fax -8310

www.ground-zero-audio.com

TITANIUM SERIES

4-Channel Class A/B Amplifier

GZTA 4125X-B

Owner's manual

(AWV2.0)

Features

• High-power 4-channel class A/B amplifier
• 2 ohms stable in stereo mode
• 4 ohms stable in bridged mode
• Variable high pass filter
• Variable low pass filter
• Adjustable bass boost control
• Active BIAS control (automatic)
• 2x Stereo RCA input
• Adjustable input sensitivity
- Turn-on delay
• Thermal protection circuit
• Short circuit protection
• Overload protection circuit
- Owner's manual enclosed

General mounting instructions

• As a precaution, it is recommended to disconnect the vehicles battery before mounting the amplifier. Note: For new vehicles, disconnecting the battery might cause various errors in your vehicle's electric system that can be cleared only by authorized service partners of your vehicle's manufacturer! Please ask your service partner first before disconnecting the battery!
• The power supply wire (+12 V) has to be protected within max. 20 cm / 8" by a main fuse holder with a fuse value matching the recommendation for your amplifier
  Note: If there is more than one amplifier connected using this power wire, the main fuse value must be equal to the sum of the recommended fuses of all connected devices. However, make sure the diameter of your power wire will be enough for the required current!

- If necessary, replace a defective fuse by a fuse with identical quality and value

- Never drill holes to the vehicle's gas tank, brake lines, to wirings or any other important vehicle parts!

- Never pass wires over sharp edges or vehicle parts due to avoid any kind of damage

- Keep the wiring away from the antenna and electronic devices contributing to radio reception

- Lay the power supply wiring always separated from speaker wiring to avoid disturbance

- The amplifier contains a temperature protection circuit that turns the device off in case of overheating. After a certain cooling time, it will turn on automatically. To avoid heat build-up, enough air supply for cooling must be provided. Never cover the surface of the amplifier's heatsink entirely

- The amplifier should NEVER be mounted onto a vibrating part or surface such as a subwoofer enclosure. This might lead to malfunction due to loosened electrical parts inside the amplifier.

- Some amplifiers offer a high-level input option, however if a pre-amplified output (RCA) is available (at the head unit), it is strongly recommended to make use of them.

Specifications

Model	GZTA 4125X-B
Amplifier type	4-channel class A/B
RMS Power @ 4 Ω CEA Standard CEA-2006-A (@ 1 kHz)	4x 90 W (1% THD+N)
RMS Power @ 2 Ω CEA Standard CEA-2006-A (@ 1 kHz)	4x 130 W (1% THD+N)
RMS Power @ 4 Ω in bridged modeCEA Standard CEA-2006-A (@ 1 kHz)	2x 260 W (1% THD+N)2x 320 W (10% THD+N)
Low pass filter	40 Hz – 4000 Hz (12 dB/oct)
High pass filter	5 Hz – 500 Hz (12 dB/oct)
Frequency response	5 Hz – 38 kHz (± 1 dB)
Total harmonic distortion (THD+N)	< 0.02%
Damping factor	> 100
Input sensitivity	500 mV – 9 V (± 5 %)
Rec. speaker wire	≥ 2.5 mm2 / 14 AWG
Rec. power wire	≥ 20 mm2 / 4 AWG
Fuse(s)	2x 35A
Dimensions (w x h x l)	230 x 53 x 396 mm
Dimensions (w x h x l)	9.06 x 2.09 x 15.59"

1	Speaker terminal	To connect the loudspeaker wiresMin. load in stereo mode 2 ohms / channelMin. load in bridged mode 4 ohms
2	Power terminal	+12V To be connected to the positive terminal of the batteryREM To be connected to the remote output of the head unit*GND To be connected to the vehicle's ground
3	Fuse(s)	Defective fuse(s) need to be replaced by same value fuses
4	Line input (RCA)	Input sockets to connect RCA wires
5	Sensitivity control	To adjust the input sensitivity
6	High pass filter	To adjust the required crossover point. Frequencies below the selected crossover point will be filtered (5 Hz to 500 Hz)
7	Low pass filter	To adjust the required crossover point. Frequencies above the selected crossover point will be filtered (40 Hz to 4000 Hz)
8	Mode switch	To setup the crossover for the required use of the amplifierFULL Full frequency range (no filter)HIGH Low frequencies are filteredLOW(BP)* High frequencies are filtered*in LOW position both, the high and low pass filters are combined to a band-pass filter (5 Hz 4000 Hz)
9	Bass Boost control	To adjust the bass boost level (0 to +12 dB at 45 Hz)
10	Status indication	POWER green ok (correct operation)PROTECT red error (protection mode)

Bridged Mode

The limited warranty for this product is covered by GROUND ZERO's regional distribution partners and their terms and conditions. For further information contact your local retailer or distributor.

Safety instruction / Manufacturer's declaration

Safety Instructions: Do not expose the device to extreme temperatures, fire, high humidity or direct contact with liquids. Do not use the device if it has been damaged or exposed to liquids. Keep the device, packaging and accessories away from children and pets to prevent accidents and suffocation.

Manufacturer's declaration: Herewith Ground Zero GmbH declares that this product complies with the directive 2014/30/EU (EMC) and further declares that this product is in conformity with the rules of the EU directives (including all applicable amendments) 2011/65/EU RoHS2 and 2001/95/EC General Product Safety directive. The full text of the Declaration of Conformity (EU) is available at the following internet address: www.ground-zero-audio.com. Electronic products contain valuable raw materials and must not be disposed of with normal household waste. At the end of its service life, please bring the device to your local recycling facility.

Respect the Music

Listening to music can be emotional, impressive, relaxing or enjoyable. At that, it doesn't really matter what kind of music is the personal favorite, whether it's Instrumental, Jazz, Electro, Latin, Classic, Rock or any other music direction. However, audio reproduction quality at each desired volume is elementary. Some music styles require higher levels while others prefer the soft tones

GROUND ZERO considers all the different wishes of customers during the development of new products. Along with this, the target is to create the most realistic sound, to transfer the soul of the music and the intention of the performer. Summarized to one phrase: RESPECT THE MUSIC!

GROUND ZERO products are engineered in Germany GROUND ZERO – international sponsor

Ground Zero GmbH

Erlenweg 25, 85658 Egmating, Germany

Tel. [phone] Fax -8310

www.ground-zero-audio.com