Inputs and Outputs Notes
MDH Power Supply: Polk Audio's
Maximum Dynamic Headroom (MDH) power supply allows the amplifier to deliver more
instantaneous power peaks, easily driving the speakers during musical peaks.
Protection: This Polk/MOMO
amplifier features 6-Way Smart System Protection (SSP) circuits. The SSP
circuits include protection against Power and Ground Reversal, Thermal and Short
Protection, Current Overdraw, and Low Impedance. When a problem arises, the
amplifier goes into an Auto-standby mode to ensure safety, reliability, and
durability. Three LEDs indicating Power, Thermal and Short/Low impedance
protection are located on the amp's top panel.
Heat Sinks: The high-density,
split-dome convection heat sinks provide more surface area than standard
fin-type heat sinks for better heat dissipation.
Removable Cover: The amplifier
has a removable cover which conceals the power and signal terminals and
amplifier controls. Once the amplifier controls have been set, the cover can be
reattached to help provide a clean-looking installation.
Switchable Inputs: The RCA
input can accept either line-level or speaker-level input signals. For
speaker-level inputs, you will need to attach RCA connectors onto the speaker
wires, and move the switch to "High". Note: RCA connectors are
not included with the amplifier.
Built-in Crossovers: The C400.4
amplifier is equipped with variable Low-Pass and High-Pass crossovers to give
you the control you need to power virtually any type or size of speaker from
tweeters to component systems to subwoofers. The front and rear crossovers can
be independently configured using the following controls:
- Slope: This 2-way switch
allows you to select a 12dB per octave or 24dB per octave slope.
- Frequency Multiplication:
This 2-way button lets you select x1 if you want a crossover frequency
between 50Hz and 500Hz, or x10 if you want a crossover frequency between
500Hz and 5000Hz.
- Crossover Frequency: This
rotary dial allows you to choose a crossover frequency between 50Hz and
500Hz when at x1 or between 500Hz and 5000Hz when at x10.
- Crossover Mode: This 3-way
switch lets you select Low-Pass (LP), Off, or High-Pass (HP) depending upon
the type of speakers you are driving with the amplifier.
Pre-EQ: The amplifier also
features a one-button preset crossover and EQ optimization circuit called the
Pre-EQ for use with Polk/MOMO component systems. The purpose of the Pre-EQ is to
allow you to bi-amplify the Polk/MOMO MM6 component speakers (item # 107MM6)
with the C400.4 amplifier, eliminating the passive crossover networks supplied
with the speakers. Using the Pre-EQ, the front channels are driving the tweeters
and the rear channels are driving the woofers. (See below for Pre-EQ
Subsonic Filter: The amplifier
has a subsonic filter (15Hz @ 24dB per octave) to eliminate super-low
frequencies which can rob amplifier power and cause damage to speakers. Note:
The subsonic filter is only activated when the Crossover Mode Selector switch is
in the LP position.
Polk/MOMO Amplifier Power
Authentication: A certificate is included with the amplifier to attest to
each individual amplifier's power performance. This Amplifier Power
Authentication indicates whether the amplifier passed the standards in Total
Quality, Response and System Protection. It lists the amplifier's serial number,
and the amp's actual power output alongside the amp's rated power. (For example,
the specific amplifier reviewed by Crutchfield had a power output of 85 watts
RMS x 4 @ 14.4V at 4 ohms. The amp is rated at 75 watts RMS x 4 @ 14.4V at 4 ohms.)
Compact Size: The C400.4
amplifier features a relatively small footprint for compact installations. The End Caps are
removable, making the amplifier only 15" wide, and allowing you to
seamlessly butt together multiple Polk/MOMO amps.
Cable Management: The End Caps
have side vents for routing power and ground wires to one side and speaker and
signal wires to the other side. The gap between the amp base and the removable
plate also provides a channel for routing wires.
and Outputs Notes
Speaker Outputs: The amplifier
has set-screw speaker outputs for 4 speakers. The terminals accept up to 8 gauge
wires and require a 2.5mm Allen wrench (supplied).
Pre-Out Terminals: The
amplifier supplies two pairs of stereo female RCA-type pass-through jacks to
allow you to easily daisy-chain additional amplifiers without the use of
Y-connectors. One pair passes through the input signal from the front channels,
and another pair passes through the input signal from the rear channels.
RCA Inputs: The RCA inputs can
accept either a low-level (Line) input signal or a high-level (Speaker) input
signal. To use the high-level input, you must attach male RCA connectors (not
supplied with the amplifier) onto your speaker wires and move the Input Type
Selector to "High".
Power Connections: The power
and ground connections set-screw terminals will accept up to 4 gauge wires. The
set screws require a 3mm Allen wrench (supplied). The remote set-screw terminal
accepts up to 10 gauge and requires a 2.5mm Allen wrench (supplied).
Remote Bass Gain Module Input: The
amplifier is equipped with an RJ-11 input (marked "Remote") for an
optional Remote Bass Gain module. The module, available from the manufacturer, allows you to
dial in the precise amount of bass you desire from the drivers seat. A 19-1/2' cable is
supplied with the module to connect the module to the amplifier. Note:
The Remote Bass Gain control only works on the rear channels and only when the
amplifier's Crossover Mode Selector is in the "LP" position.
Pre-EQ: When using the C400.4
amplifier to bi-amplify the Polk/MOMO MM6 component systems, the specifications
of the Pre-EQ crossover and optimization circuit are as follows:
- Front (tweeters):
- Filter Function: High
- Corner Frequency: 4.0kHz
- Slope: 12dB/octave
- Filter Function: Shelf
- Corner Frequency: +2dB @
- Bandwidth: 6dB/octave
- Rear (midranges):
- Filter Function: High
- Corner Frequency: 38.4Hz
- Slope: 12dB/octave
- Filter Function: Low
- Corner Frequency:
- Slope: 18dB/octave