Alpine PDX-5 Power Amp (from Alpine's web site)

CEA-2006 Power Rating (4Ohm@14.4 V =1% THD+N)
S/N 76dBA (Ref: 1W into 4Ohm & 2Ohm for Mono ch.)
75W x 4 + 300W x 1

From the best-selling high-end amplifier line in the U.S., Alpine’s 
PDX line now comes in 5 channel form– meet the PDX-5! This is your 
answer to building a great system with only one amp. The PDX-5 still 
embodies the same great chassis size and cosmetic look as the rest of 
the PDX lineup, with 90% efficiency at all power levels for precise, 
powerful sound.

Good things really do come in small, stackable packages. Who knew 
something so small could pump out so much power? The Alpine PDX series 
amplifiers are for the true car audio enthusiast – for those who want 
the best power, sound quality, and efficiency, all from a compact size. 
Get the most out of your system with Digital PDX.

Accurate Dynamic Sound Reproduction
Alpine’s goal is to deliver the best sound quality possible. With the 
PDX series, digital switch-mode amplification yields incredible sound 
quality. Advances in the PDX design include improved feedback circuitry 
to faithfully reproduce the input signal for improved dynamic range and 
higher fidelity. If you’re listening to your favorite rock song, your 
amp is ready to jump from loud to calm and back again with ease.

Installation Flexibility
The PDX amplifiers’ unique design allow for a clean, easy, and fast 
install in your car! All the controls and wiring connections are in one 
convenient location.

Save Space
PDX amplifiers are 60% smaller than previous models with the same output 
power. Install your amps easily without sacrificing valuable room, power 
and performance.

Smart Stacking
The PDX amplifiers feature a smart stackable design. All PDX amplifiers 
are the same size, regardless of the amount of power or channel specifications. 
Their exclusive design allows them to be stacked vertically on top of one 
another. This is an industry-first installation option that saves a ton of 
space in the trunk or under a seat.

Low Resistance, High Current Speaker Terminals
Quick disconnect plugs with low resistance and high current capabilities 
make installing quick and easy.
		
More Power, Better Sound
PDX amplifiers deliver outstanding sound quality. The revolutionary design 
of the PDX incorporates improved feedback circuitry and power supply 
filtering system, plus a damping factor that is 350% better than Class A/B amps.

Unprecedented Sound Matching & Accuracy
A highly effective Powerful Feedback Circuit accurately compares the 
amplifier’s output against the original music signal. If there are any 
differences found between the two, the feedback circuit automatically 
removes the distortion in real-time! This keeps your music true to the 
original recording without added distortion or filter noise.

Same Power Output - 2O or 4O Configuration
PDX amplifiers have the unique capability to deliver the same power output 
regardless of 2O and 4O loads. This provides the ultimate in system 
flexibility and subwoofer configuration diversity.

Power On Demand*
A combination of an advanced power supply, Class-D design, and switch-mode 
digital amplification allow PDX amplifiers to stay extremely efficient at 
all power levels. This produces less heat, eliminating the need for large 
heat sinks, just another reason why they can be much more compact than 
conventional amps.

The PDX amplifiers use Direct FETs device to make switch-mode digital 
possible. Direct FETs are very small output devices that take up less 
room and they switch on and off extremely fast when needed. Their ultra 
high-speed switching capabilities allow them to perform at frequencies 
that other Class-D amplifiers struggle to reproduce. This provides control 
over power consumption, and cooler operation.

*Full Range PDX Amplifiers Only (PDX-4.150, PDX-4.100, PDX-2.150 & PDX-5)