Boosted Rail Technology: The PBR300x4 uses Boosted Rail
Technology (BRT), an efficient design that doesn't use a switching power supply.
The PBR300x4's average efficiency is more than 75%, meaning it doesn't generate
much heat and can maintain a small footprint.
Signal Input: The PBR300x4 is compatible with either
line-level (RCA) or speaker-level inputs. The included Molex-to-RCA is used
in both cases; the RCA end is cut off for connection to speaker wires.
Auto Turn-on: When using speaker-level inputs the amp will
automatically turn on when it senses an input signal (4 volt minimum). The
threshold voltage (DC offset) for auto turn-on is adjustable from 4 volts to
Dynamic Thermal Management (DTM): DTM Evenly distributes
excess heat across the entire extruded aluminum heatsink.
MEHSA³: MEHSA³ (Maximum Efficiency Heat Sink Application-Third
Generation) is a Rockford Fosgate proprietary process that increases the heat transfer
from the MOSFET devices to the heatsink. The multi-layer insulated metal MEHSA substrate
operates with minimal thermal resistance, spreading heat both downward and outward to
quickly dissipate heat from each device across the heatsink. This allows greater power
output, enhanced thermal stability, and maximum reliability.
NOMAD: NOMAD (NOn-Multiplying Advanced Decision) is an intelligent
protection circuit that uses an analog computer to make real time decisions regarding
temperature, voltage, current and impedance. The unit is protected without limiting
sound output unless needed.
DSM (Discrete Surface Mount): In the manufacturing process
high speed robotics are used to place 1% tolerance parts and large board traces.
DSM improves the efficiency of the circuit, decreases cross-talk from other discrete
components and lowers operating temperature.
LEDs: The Power/Protect LED on the right side of the amp
illuminates blue when the amp is turned on and operating normally; it illuminates
red when one of the protection circuits has engaged (short circuit, impedance too
low, or temperature too high). The BRT LED on the left side of the amp illuminates
white when the boost mode is engaged.
Crossover: The front and rear channels have independent crossover
switches. Each can be set to low-pass, all-pass (crossover is bypassed), or high-pass.
The crossover point is fixed at 80 Hz and the slope is 12 dB/octave.
Gain: The front and rear channels also have independent input
gain controls, adjustable from 150mV to 11V.
2/4 Channel: When using only one set of inputs, set this switch
to 2-channel and connect the inputs.
DC Offset: The DC offset threshold voltage for the auto turn-on
circuit is adjustable from 4 volts to 6 volts (useful with speaker-level inputs).
Power Connections: The power, ground, and remote turn-on
terminals are c-clamps on a removable plug. Each terminal will accommodate up
to 10-gauge wire (Rockford recommends 10-gauge minimum for the power and ground
wires). A flat blade screwdriver (not supplied) is required to tighten/loosen the
terminals. There is no fuse on the body of the amp, so an external 30-amp fuse
(not included) must be installed in the power wire. If a wiring kit is used that
includes a different value fuse, the original should be replaced with a 30-amp
Signal Input: The included input harnesses have Molex plugs
on one end (plugs into the amp) and female RCA plugs on the other. When using
speaker-level inputs the RCA end is removed and the four individual wires are
Speaker Output: The included speaker output harnesses have
Molex plugs on one end (plugs into the amp) and tinned bare wires on the other.