POWER AMPLIFIER
Owner’s Manual
Mode d’emploi
Bedienungsanleitung
Manual de instrucciónes
TEMP
PROTECTION
POWER
ON OFF
CLIP
AB
SIGNAL
Introduction
Thank you for purchasing a Yamaha C450/320/160 series power amplifier.
This series of audio amps was developed from Yamaha's wealth of experience in building PA
equipment and its tradition of careful attention to every detail of circuit design. These amps
feature high power and superb quality together with superior reliability and stability, guaranteeing the highest possible audio performance.
Main features of the C450/320/160 series
• Two types of input (balanced XLR type connectors and barrier strip), and barrier strip
for outputs are provided.
• Three operating modes are provided: STEREO mode in which CHANNEL A and B
operate independently, PARALLEL mode in which a mono source is output by two amp
systems, and BRIDGE mode in which the unit operates as a single high-power amplifier.
• A SIGNAL indicator and CLIP indicator is provided for each channel.
• The PROTECTION indicator shows the status of protective circuitry such as power-on/
off protection, output muting, and the DC detection circuit. The TEMP indicator warns
of heat sink overheating.
• Variable-speed low-noise fan(s) ensures high reliability even under demanding conditions.
• The C450/320/160 has implemented “EEEngine”, Yamaha’s epochal amp drive
technology to create an unrivaled high-efficiency drive.
The EEEngine’s energy-saver/low-heat-generation design has reduced power consumption to 50% or less, and reduced heat generation to 35% or less (in field applications,
compared to Yamaha’s previous models), and has lead to a reduction in energy cost and
to less-restrictive installation requirements related to heat generation.
This owner's manual covers the three models C450, C320 and C160. In order to take full
advantage of your power amp and enjoy long and trouble-free operation, please read this
owner's manual carefully before use.
IMPORTANT NOTICE FOR
THE UNITED KINGDOM
Connecting the Plug and Cord
WARNING: THIS APPARATUS MUST BE EARTHED
IMPORTANT: The wires in this mains lead are coloured in accordance with
the following code:
GREEN-AND-YELLOW : EARTH
BLUE : NEUTRAL
BROWN : LIVE
As the colours of the wires in the mains lead of this apparatus may not
correspond with the coloured markings identifying the terminals in your
plug, proceed as follows:
The wire which is coloured GREEN and YELLOW must be connected to
the terminal in the plug which is marked by the letter E or by the safety earth
symbol or coloured GREEN and YELLOW.
The wire which is coloured BLUE must be connected to the terminal which
is marked with the letter N or coloured BLACK.
The wire which is coloured BROWN must be connected to the terminal
which is marked with the letter L or coloured RED.
* This applies only to products distributed by YAMAHA KEMBLE
MUSIC (U.K.) LTD.
Precautions
1. Avoid excessive heat, humidity, dust and vibration.
Keep the unit away from locations where it is likely to be
exposed to high temperatures or humidity — such as
near radiators, stoves, etc. Also avoid locations which
are subject to excessive dust accumulation or vibration
which could cause mechanical damage.
2. Ventilation
Allow a distance of 10 cm between the unit and the wall
so that heat generated from the unit will be released
effectively. Also, allow enough space between the unit
and other devices. If you mount the unit in an audio rack,
keep a space of 10 cm on the top panel, and a space of
1 cm to the side panel. Remove the rear panel of the rack
or open a vent hole. If heat release is inadequate, the unit
will retain heat inside the unit, which may cause a fire.
3. Avoid physical shocks.
Strong physical shocks to the unit can cause damage.
Handle it with care.
4. Do not open the case or attempt repairs or modifications yourself.
This product contains no user-serviceable parts. Refer
all maintenance to qualified Yamaha service personnel.
Opening the case and/or tampering with the internal
circuitry will void the warranty.
5. Make sure power is off before making or removing
connections.
Always turn the power OFF prior to connecting or
disconnecting cables. This is important to prevent damage to the unit itself as well as other connected equipment.
6. Handle cables carefully.
Always plug and unplug cables — including the AC cord
— by gripping the connector, not the cord.
7. Clean with a soft dry cloth.
Never use solvents such as benzine or thinner to clean
the unit. Wipe clean with a soft, dry cloth.
8. Always use the correct power supply.
Make sure that the power supply voltage specified on the
rear panel matches your local AC mains supply. Also
make sure that the AC mains supply can deliver more
than enough current to handle all equipment used in your
system.
Contents
Controls and Functions ............................................................. 2
Front Panel........................................................................... 2
Rear Panel ........................................................................... 3
Modes: STEREO/PARALLEL/BRIDGE................................ 4
SPEAKER IMPEDANCE...................................................... 4
Caution for Speaker Connection............................................... 5
Rack Mounting .......................................................................... 6
Mounting in an EIA standard rack ....................................... 6
Mounting four or fewer amps in an open-backed rack......... 6
Mounting five or more amps, or when (even with four or
fewer units) the back of the rack cannot be left open .......... 6
Portable Rack Mounting ...................................................... 7
Positioning the Housed Amplifier......................................... 7
Specifications ............................................................................ 8
General Specifications......................................................... 8
Block Diagram...................................................................... 9
Dimensions .......................................................................... 9
Performance Graphs.......................................................... 10
Troubleshooting ...................................................................... 10
Controls and Functions
■ Front Panel
23
TEMP
PROTECTION
POWER
ON OFF
1
1 POWER switch and indicator
This is the main POWER switch. Press to power ON
the amplifier. Press again to power OFF. The POWER
indicator lights up when the amplifier is powered ON.
2 TEMP indicator
When the temperature of the heat sink exceeds 85
degrees Celsius, this indicator will light red.
3 PROTECTION indicator
This red LED indicator lights up for approximately 3
seconds when the amplifier is powered ON, indicating
that the soft-start protection system is working. No
sound is output during soft-start up. If one of the
protection systems is activated during normal use, this
indicator lights up and no sound is output. The
speaker system is actually disconnected from the
amplifier outputs when this indicator lights up. The
protection systems are activated when overheating
occurs or a DC voltage is present at the amplifier
outputs. If the problem is corrected, the protection
systems deactivate automatically, this indicator goes
out, and normal amplifier operation is resumed.
4
CLIP
AB
SIGNAL
5
4 CLIP indicators
These red LED indicators light up when the respective
channel’s output signal distortion exceeds 1% (i.e.
clipping). Output signal clipping is usually due to
excessive input signal levels.
5 SIGNAL indicators
These green LED indicators light up when the
respective channel’s output signal exceeds 2 Vrms.
This is equivalent to 1/2 watt into 8Ω, 1 W into 4Ω.
2