Specifications
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2005 Product Application Guide
Power Guard Circuit
This by far is the most important feature the APA4300HX
offers, as the amplifier’s input stage prevents the genera-
tion of clipping distortion by holding down the gain when
overdrive distortion is detected at the output stage. By
removing only distortion elements, the amplifier protects
speakers from potential damage while also maintaining
the amplifiers superior sound qualities.
4-Part Digital Meter
The APA4300HX offers this unique feature so users will
always be in tune with its performance. This four-part
digital meter allows the user to monitor the amplifier’s
real-time power output level and consumption, voltage
level and internal temperature.
Low-Loss High-Output Power Supply
Clarion equips the APA4300HX’s power supply with a
high-performance, low-loss, MOS-FET-based PWM-type
DC/DC converter. The amplifier’s circuit structure boasts
large-capacity, low-impedance capacitors, and a large
toroidal choke coil, a super thin circuit board and a copper
bus bar. The result is a power supply that maintains stabil-
ity, even during sudden signal changes.
Toroidal Choke Coils
Used in the power supply circuitry, these type of coils are
resistant to magnetic noise and have a low DC resistance.
This contributes to the amplifier’s high efficiency, low-
noise power supply.
Amplifier Technologies
Clarion’s amplifier power supply technologies include
an input voltage compensation circuit, an active regulator
feedback circuit, and voltage-input protection. The
incorporated double-sided circuit boards use heavy-duty
copper/tin-plated bus bars and direct-mount connectors.
Built-in crossovers are standard on all amplifier
models. Other features include a discrete driver and high-
current output transistor pairs, along with a solid-state
muting circuit.
These features provide Clarion’s amplifier line with
stable and well-protected power supplies, quieter opera-
tion, better signal-to-noise ratios and transient response,
as well as the ability to handle lower impedance loads.
This translates into amplifiers with great reliability
and flexibility.
Mixed Mode Operation
This feature is the key behind the versatility of the
APA4320 and APA2160 amplifiers. By utilizing an
inverting circuit, a single 2-channel amplifier can drive
multiple satellite speakers in stereo, as well as a sub-
woofer in a bridge mono configuration. This eliminates
the need for active crossovers while allowing for a
multi-speaker system.
2-Ohm Stability
Clarion APA4320 and APA2160 amplifiers are designed to
driver lower impedance loads for increased power output
and can be bridged for mono operation across a 2-ohm
load. This allows the amplifiers to run multiple speakers in
more complex systems. The result is an amplifier that can
provide 150% more power in 2-ohm stereo, or more than
300% in 2-ohm bridged mono.
Multi-Channel Amplifiers
Clarion’s multi-channel amplifiers provide four channels
of amplification on one circuit board, all enclosed in a
single chassis. Moreover, all models are equipped with
on-board high-pass/low-pass electronic crossovers.
This configuration provides maximum system flexibility
using a single amplifier. For example, the front channels
can drive full-range speakers with front crossovers “off,”
while rear channels are set to low-pass and bridged to
drive a single subwoofer. Or, the front channels can be set
to high-pass to drive a pair of satellite speakers, and rear
channels set to low-pass to drive a pair of woofers.
Pulse-Width-Regulated MOS-FET Power Supply
This type of power supply converts the battery voltage to
a higher voltage (i.e., +30 volts or greater) than the ampli-
fier requires for maximum power output. Unless the power
supply increases 12-volt battery power, the amplifier can-
not produce more than about 25 watts (rms). The power
supply delivers the proper amounts of current and voltage
to the amplifier’s output stages over a wide range of
loads, and varies the pulse width to accommodate differ-
ent load conditions.
Pulse-width regulation adjusts the width of the power
supply’s switching pulses to serve constantly-changing
audio power needs. When music dynamics increase, or
the volume is raised, the pulses stay on longer to charge
the power supply capacitors across the DC rail in the
power supply.
By using this type of power supply, Clarion can build a
smaller amplifier that generates less heat and is more
efficient.
Another advantage to this type of supply is that it can
deliver its rated power over a wide range of input voltages.
This means the amplifiers will deliver their rated power
over a voltage swing of 11.6 to 14.7 volts. The result is
an amplifier that can produce maximum power into a
2-ohm load without losing output power under lower
voltage conditions.
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2005 Product Application Guide
Amplifier Circuit Information
The input and output of Clarion’s amplifiers incorporate
complex circuitry for both the input and output sections.
This offers better noise suppression, fast transient
response and minimum distortion. This includes high-
impedance differential input stages, global feedback,
and premium devices with very high slew rates.
High-impedance differential input stages separate the
input signal ground from the common chassis ground.
This creates a very effective ground-loop isolation circuit
that reduces the possibility of charging system noise from
entering the signal path.
Feedback is a method of controlling the distortion in an
amplifier’s output by feeding a portion of the output signal
to the input of the amplifier. At Clarion, we use global
feedback circuits instead of the more commonly-used
local feedback type (i.e., the ability of a device to quickly
respond to an input signal). This reduces distortion,
boosts the signal-to-noise ratio, and increases the amplifi-
er’s overall transient response.
These advanced circuit topologies ensure that Clarion’s
amplifiers will accurately reproduce all the dynamics and
subtleties found in today’s digital recordings. At the same
time, noise suppression circuits work to effectively elimi-
nate induced electrical system noise, which contributes to
the dynamic range of the amplifiers.
Cosmetic Design: The APA4320 and APA2160
The versatility these two amplifiers offer is directly related
to the compact design both offer. This is made possible by
an exclusive heat sink design and aluminum die-cast
body, which offers efficient heat dissipation during opera-
tion. This eliminates the need for an internal fan, resulting
in an amplifier with a smaller footprint. Clarion further
enhances the look of the amplifier with a stylish oval-
shaped emblem, which incorporates three blue LEDs.
Gold-Plated RCA Connectors and Terminals
Superior conductivity is achieved by using gold-plated
RCA and power supply terminals to minimize contact
resistance and noise. Moreover, because gold is un-
affected by external magnetic fields, magnetic
distortion is reduced.
Gapped E-Core Choke Coils
Utilized in the power supply, the Gapped E-Core choke
coils offer low impedance and resistance to harmful
magnetic impedance. This results in a more efficient
amplifier and a low-noise power supply.
Variable High-/Low-Pass Crossover
Amplifiers armed with these two features allows users
to make frequency adjustments over all channels so that a
multi-amplifier and subwoofer system can be configured
with ease.
Amplifier Breakdown
APA4300HX4/3/2-Channel Amplifier
• 600 Watts Maximum Power Output
• Bridgeable 3/2-Channel Mode Operation
• Power Guard Circuit
• Low-Loss Power Supply
• Stable Down to 1-Ohm Load in Stereo
• Variable 4-Channel Low- and High-Pass Filter
(50 to 200Hz)
• Bass Extender (40Hz to 120Hz, 0 to +12dB)
• Four-Part Digital Display
• Aluminum Housing Built-In Cooling Fan
• Speaker Level Input Terminal
• 100kHz Frequency Reproduction
• Gold-Plated Connectors
APA4320 4/3/2-Channel Amplifier
• 640 Watts Maximum Power Output
• Bass Extender Control (0 to 15dB @ 45Hz)
• Adjustable High- and Low-Pass Crossover
(55Hz to 550Hz, 12dB/Oct.)
• Mixed Mode Operation
• 3/2-Channel Operation
• MOS-FET Output Design
• Double-Sided FR4 PC Board
• Gold-Plated RCA Connectors
APA2160 2/1-Channel Amplifier
• 320 Watts Maximum Power Output
• Bass Extender Control (0dB to 15dB @ 45Hz)
• Adjustable High- and Low-Pass Crossovers
(55Hz to 550Hz, 12dB/Oct.)
• Mixed Mode Operation
• 2/1-Channel Operation
• MOS-FET Output Design
• Speaker Level Input Terminals
• Double-Sided FR4 PC Board
• Gold-Plated RCA Connectors
Power Guard
Clarion Amp
Conventional Amp
More Current Supplied Less Current Supplied
Higher Audio Signal
Lower Audio Signal
Pulse Width Increases
Pulse Width Decreases