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AMH PROFESSIONAL AUDIO POWER AMPLIFIER INSTALLATION AND OPERATION MANUAL
Power Requirements
Power consumption for your model of the AMH Series amplifier is indicated
on the rear panel for 1/8th output power.
Ensure that your mains voltage is the same as the rear panel mains voltage
marker (+/- 10%).
Mounting
Your amplifier is designed for standard 19” rack mounting and occupies
2 EIA rack units (3.5”). The mounting centres are:
Vertical: 3.0” (76.2mm)
Horizontal: 18.2” (462.5mm) to 18.7” (473.8mm).
The slots in the mounting flange will accept bolt diameters up to 1/4”
(6.35mm).
Cooling
Each channel of your new AMH Series amplifier is cooled by an axial fan which
draws cool air from the front of the amplifier and expels the heated air out the
rear of the amplifier. These amplifiers offer two speed fans that run at half speed,
switching to full speed when the internal heat-sink temperature exceeds 65ºC.
An unrestricted airflow into and out from the amplifier must be provided. Any
restriction of the airflow will cause heat to build up within the unit and possibly
force the unit into its thermal shutdown mode.
If the amplifiers are to be operated in an environment where the airflow is
restricted such as sealed racks, the cooling should be supplemented by extra
cooling fans to evacuate the heated air and aid the flow of cool air through
the unit.
Input Wiring
IMPORTANT:
Do not directly connect pin 1 on the amplifier’s input
or strapping XLR, to the amplifier’s chassis, speaker ground or power
ground!
WARNING:
Input signal ground is not to be used as a safety ground
(earth).
The input to your amplifier is a balanced 3-pin configuration and requires all
three pins to be connected. Only high quality twin-core shielded cable should
be used.
When wiring for a balanced source, the connector going to the input of your
amplifier should be wired as follows:
Pin 1 = GROUND / SHIELD
Pin 2 = HOT (In Phase - non inverting)
Pin 3 = COLD (Reverse Phase - inverting)
When wiring from an unbalanced source you must ensure that pin 3 is
connected to pin 1 (input ground), either by linking the pins in the input
connector or by the source equipment’s output wiring.
When wiring for an unbalanced source:
Pin 1 = GROUND/SHIELD
Pin 2 = HOT (in phase with the amplifier’s output)
Pin 3 = GROUND/SHIELD (joins to pin 1)
NOTE:
In-line XLR connectors often have a termination lug that
connects directly to the chassis of the connector.
IMPORTANT:
Do not link this lug to pin 1 at the amplifier’s input
as it will defeat the amplifier’s input grounding scheme.
Output Wiring
When wiring to your speakers always use the largest gauge wire your
connector will accept. The longer the speaker lead, the greater the losses will
be, resulting in reduced power and less damping at the load. We recommend
using a heavy duty, two core flex (four core flex if biamping) 10 to 12 gauge
(2mm2 to 2.5mm2 or 50/0.25 or equivalent) as a minimum.
Binding Post Outputs
When terminating to the 4mm binding post (banana jack) output connectors,
banana plugs or bare wires can be used. The red terminal is positive and the
black terminal is negative (ground).
If running in BRIDGE mode, only the red binding posts are used.
When bridging, Channel 1 provides the positive output to the load and Channel 2
provides the negative output to the load.
Speaker Outputs
When using the 4 pole speaker connector for speaker output, use only the
mating 4 pole in-line connector. This connector is designed so that both
channels can be fed from a single connector.
Two speaker connectors are provided on the amplifier.
The ”Channel 1” speaker connector actually carries both Channel 1 and
Channel 2 outputs (see Speaker Connector Wiring Diagrams).
The ”Channel 2” speaker connector carries the Channel 2 output only.
This arrangement allows you the option of connecting to the outputs separately
or together. Connecting through a single connector has the advantage of
minimising connections, preserving phasing and simplifying channel allocation,
which is particularly important when bi-amping or in bridge mode.
IMPORTANT:
Do not overload your amplifier by connecting the
channel B output twice!
Channel 1 is used as the “dominant” channel and when sourcing a dual output
from Channel 1, the following standard should normally be used (depending
on speaker system wiring):
Channel 1 = Left or Low Frequencies.
Channel 2 = Right or High Frequencies.
When in bridge mode:
Pin 1+ = Bridge Output Positive
Pin 2+ = Bridge Output Negative
INSTALLATION
