BLAM RA251D Ultra Compact OEM Compatible User Manual
- June 12, 2024
- BLAM
Table of Contents
BLAM RA251D Ultra Compact OEM Compatible
CAUTION
Thank you for using the RA 251 D amplifier, to ensure the best performance from your amplifier, please read the Operating Manual before using the amplifier.
TECHNICAL FEATURE
Compatible with OEM head units
- High-level inputs with auto-turn on
- RCA low-level inputs: 0.3 V/15 V
- Power (4 Ω): 150 Watts RMS
- Power (2 Ω): 250 Watts RMS
- Low-pass crossover: 35 Hz — 500Hz
- Bass boost adjustable +12 dB (45 Hz)
- Signal/noise ratio: 90 dB
- Protections: short circuit / low impedance / reversal of polarity / heat protection
- External wired remote control
- Dimensions (L x W x H ): 6.2″ × 1.4″ x 3.6″ – 158 mm x 36 mm x 91.4 mm
POWER CONNECTIONS
Connect an empty fuse holder within 18” (45 cm) of the car battery, and run 8 gauge (or heavier) cable from this fuse to the amplifier location. Then connect the fuse holder to the “BATT+”. Connect the ground terminal to the closest point on the chassis of the vehicle. Keep this ground wire to less than 39” (100 cm) in length. Ensure that the contact surface is free of paint or rust so that the connection between the terminal and the chassis is effective.
PLOW LEVEL INPUT WIRING
Low-level (RCA) input wiring is preferred for best audio performance. Most trunk or hatchback installations will require a 15-20 feet RCA cable, while pickup trucks and under-seat installations will require a 6-12 feet RCA cable. Always usa a high quality cable. Connect to remote turn-on terminal head unit.
NOTE: do not connect BOTH the high level and low level inputs from your receiver to your amplifier at the same time! Connect the remote terminal.
HIGH LEVEL INPUT WIRING
The high level input(s) should only be use if the RCA output are not present, connect the speaker outputs from the receiver to the high level input connector of the amplifier. Be sure to observe polarity to avoid audio phase problems. The AUTO POWER ON is for high level connetions. The subwoofer turns on automatically when there is a signal on the input.
NOTE: do not connect BOTH the high level signal and low level inputs from your receiver to your amplifier at the same time!
DUAL SUBWOOFER WIRING CONFIGURATION
SINGLE SUBWOOFER WIRING CONFIGURATION
TROUBLE SHOOTING
This amplifier has multi-layer protection features to prevent damage from misuse or faulty conditions to ensure long lasting life of your investment. If the unit senses excessive heat, short circuited speakers, overload, or voltage fluctuation outside of the working range the protection indicator light will turn red and the unit will turn off. In order to solve this problem, you should turn all levels down, power off the unit, then carefully check the installation for wiring mistakes or shorts. If the amplifier is excessively warm the protection light will not turn on as the unit will turn off to protect itself from overheating. Let the unit cool down for 30 minutes and try again. If the unit work, try moving the amplifier or make sure nothing is covering it so it can vent heat off of the heatsink. Before you remove or uninstall the amplifier, refer to the list below for suggested solutions.
Amplifier doesn’t turn on or not output:
- Check the fuse(s), not just visually, but with a continuity meter and all 12+ volt, remove and ground connection. It is possible for a fuse to have poor internal connections, take the fuse out of the holder for the testing.
- Check the input signal from the source unit using an AC voltmeter to measure the voltage while it’s being played. The voltage should be from 0.3 to 15 volts from the RCA cables.
- Check to ensure that the speaker wires are making a good connection to the amplifier and the subwoofers.
Amplifier goes into protection:
- Check the chassis ground connections.
- Check amplifier controls for errors, input level or crossover setting.
- Check the speaker wires for a possible short, either between the positive and negative leads or between a speaker lead and the vehicle’s chassis ground.
- Check the nominal load impedance to verify that the amplifier is driving a load equal or greater than 2 ohm.
- Check the input signal cables to make sure signal is present at the amplifier inputs and the cables are not pinched or loose. It may be helpful to try a different set of cables/or a different signal source to be sure.
- Check speaker wiring for reverse polarity.
Customer Support
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