Page 10
Reference Manual
Macro-Tech
®
24x6 & 36x12 Power Amplifiers
3 Installation
3.1 Mounting
Macro-Tech amplifiers are designed for standard 19
inch (48.3 cm) rack mounting as well as “stack” mount-
ing without a cabinet. In a rack cabinet, it is best to
mount them directly on top of each other. This provides
efficient air flow and the best support.
Important:
Due to the weight of the unit, it should be
securely fastened at the back of the cabinet.
19 in
48.3 cm
16 in
40.6 cm
3.5 in
8.9 cm
2.5 in
6.35 cm
SIDE VIEW
Fig. 3.1 Mounting Dimensions
Fig. 3.2 Top View of a Rack-Mounted Unit
AIR
FLOW
AIR FLOW
AMPLIFIER
(TOP VIEW)
RACK
CABINET
16 in
40.6 cm
2 in
(5 cm)
MIN.
IMPORTANT: Be sure the back of
the amplifier is supported.
17 in
43.2 cm
AIR
FLOW
3.2 Cooling
NEVER block the amplifier’s side vents or front air in-
take. Allow at least 45 cubic feet (1.3 cubic meters) of
air flow per minute. All empty spaces in the rack cabi-
net should be covered with blank panels to prevent im-
proper air flow. The amplifier’s air flow should be
augmented with a rack cooling system if its load is less
than 4 ohms and the amplifier must operate at high out-
put levels. See Section 7 for additional information on
thermal dissipation.
If the air supply is unusually dusty, it may be necessary
to pre-filter it using commercial furnace filters, etc., to
prevent rapid loading of the unit’s own air filter. When
needed, the unit’s filter can be cleaned with mild dish
detergent and water (see Section 4.5).
When mounting the amplifier in a rack cabinet, the side
walls of the rack should be at least 2 inches (5 cm) away
from the chassis as shown in Figure 3.2.
Tip:
An easy way to verify adequate cooling is to ob-
serve the ODEP indicators while the amplifier is operat-
ing under worst-case conditions. If the indicators dim,
additional cooling is recommended.
If your rack cabinet has a front door that could block air
flow to the amplifier’s air intakes, you must provide ad-
equate air flow with either a grill in the door or by pres-
surizing the air behind the door. Wire grilles are
recommended over perforated panels because they
tend to create less turbulence.
A good choice for pressurizing the air behind a rack
cabinet door is to mount a “squirrel cage” blower inside
the rack (option 1 below). At the bottom of the rack,
mount the blower so it blows outside air into the space
between the door and the front of the amplifiers, pres-
surizing the “chimney” behind the door. This blower
should not blow air into or take air out of the space be-
hind the amplifiers. For racks without a door, you can
evacuate the rack by mounting the blower at the top of
the rack, so that air inside the cabinet blows out the
back (option 2 below).
BLOWER
(OPTION 2)
BLOWER
(OPTION 1)
AIR
FLOW
FRONT
OF
RACK
DOOR
AIR
FLOW
EQUIPMENT
RACK
(SIDE VIEW)
Fig. 3.3 Proper Air Flow in a Rack Cabinet
