This product is a vintage Polk model and is not available for sale, but it may still be available in some stores as a closeout or used product. The following text is taken from the original sales brochure for this product and does not reflect current availability. If you happen to have any question or concerns about this product, or any other Polk Audio product, feel free to contact our Customer Service Department at 1-800-377-7655 Monday - Friday, 9am - 5:30pm EST


Monoblock mobile audio amplifier for compact subwoofers

Available Finishes:

Pure Performance.

The PA400.1 monoblock has a power output rated at 300 Watts RMS x 1 at 4 ohms with ≤ 1% THD+N. The amplifier’s signal to noise ratio is -60 dBA (reference 1 Watt into 4 ohms). It is also capable of 600 Watts RMS x 1 at 1 ohm with ≤ 1% THD+N.

PA400.1 Features:

Monoblock amplifier for subwoofer use.

800 Watts x 1 (1 ohm) dynamic power.

1 ohm stable design can drive even the most demanding subwoofers.

Power and ground terminals accept bare wire up to 4 AWG. Terminals use standard #2 Phillips head screwdriver- no more hex wrenches to lose or strip!

High-speed MOSFET switching power supply and high current bipolar output transistors pump maximum voltage and high current to your speakers or subwoofers.

Double layer fiberglass epoxy printed circuit boards for more rigidity and less shrinkage, with plated through-holes instead of jumpers, for twice the amount of component contact area. Efficient layout packs more circuitry, with tighter component tolerances, into a smaller circuit board for a smaller overall amp footprint.

6-way Smart System Protection (SSP) circuits: Power and ground-reversal protection, thermal and short protection, current overdraw and low impedance protection circuits with auto-standby mode ensure safety, reliability and durability.

Anodized extruded brushed-aluminum cover for maximum heat dissipation and great looks!

Cast aluminum textured end caps for optimized heat dissipation and hiding of connectors. Solid aluminum logo and model panel back lit in cobalt blue.

Adjustable 12 dB/octave low-pass crossover (30-250 Hz).

Switchable 8 dB bass boost at 40Hz for extra bass thump.

Switchable 24 dB/octave subsonic filter protects ported subwoofers.

Switchable 180° phase inversion for easy sub to main integration.

Variable input gain optimizes match with different signal sources (250mv to 7.5V).

RCA outputs for easy daisy chaining of other amplifiers.

Mounting hardware with rubber isolation grommets and extra fuses included.

Light bar/fan output-Connect an optional LED light bar or cooling fan for custom installations.

Multi-color status LED gives instant information on amplifier operation.

Remote subwoofer level adjuster included.


Total Frequency Response20-250 Hz 
Signal-to-noise (Referenced to rated power)98 dBA
Protection Circuitry2 x 25 amp fuse, Power and Ground-Reversal Protection, Thermal and Short Protection, Current Overdraw and Low Impedance Protection circuits 
Subsonic FilterYes, Switchable 
Low Pass Filter
Filter Slope12 dB/Oct 
Filter Frequency30-250 Hz 
Effective Damping Factor150 
CEA2006 Rating200 watts / 4 ohms
Input Impedance20 k ohms
Max Sensitivity150 mV to 7.5 dB


Product Weight (each)9.00 pounds
With Panels
Height2 9/16" (6.51cm) 
Width10 9/16" (26.83cm) 
Depth10 1/4" (26.04cm) 

Amplifier Specs

Bass Boost Characteristics+8 dB @ 40 Hz Hz


Total Shipping Weight11.00 pounds

Amplifier Power Specs

RMS Power at 14.4V
Watts per channel NOT bridged @ 1 kHz
4 ohms200 watts
2 ohms300 watts
1 ohm400 watts

Specifications, dimensions and features subject to change without notice. For more information call us at 1-800-377-7655 (USA and Canada). Outside of North America call +1 (410) 358-3600.

PA400.1 Media

PA400.1 Literature

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PA400.1 Accessories