ISP Technologies VMAX 150C - Manual (Page 8)

THERMAL CONDITIONS
The ISP VMAX is capable of producing in excess of 400 watts RMS at full power. This
generates heat that must be dissipated in order to maintain reliability and insure the amplifier
components stay within their operating temperature specs. To accomplish this, the amplifier is
mounted on a heatsink that is exposed on the side of the cabinet. As the heatsink gets hot air
will flow over the fins on the heatsink by convection. When using the VMAX as a floor monitor
it is recommended that you do not block or obstruct the airflow by the side-mounted heatsink.
The VMAX has large rubber feet on the bottom of the cabinet, which will allow air to move out
from the bottom bass port and provide cooling for the internal amplifier. When using the VMAX
as a top box or mounted on a pole allow a minimum of 6 inches of clearance in the back so as
to provide proper cooling of the internal amplifiers.
NOTE: Under continuous high-level use,
the external heatsink will get extremely hot. Care should be taken to avoid touching the
heatsink until it cools. The internal amplifiers have thermal protection and will protect
the D-CAT amplifiers if the temperature exceeds a safe operating point.
The internal D-CAT amplifiers are thermally protected internally via a thermal switch, which will
attenuate the signal 30db if the heatsink temperature exceeds a safe operating temperature. If
the amplifier reaches the point where thermal limiting occurs, the Red Limit LED will light when
the amplifier is in thermal protection. When the temperature drops below this threshold point,
full signal will be restored. Tests have shown under extreme conditions that cycling will occur
approx. (40 sec. ON, 10 sec. OFF). Under extreme conditions, such as when ambient
temperatures are too high (hot rooms, extreme outdoor temperatures) it is recommended to
use a fan to cool the fins and reduce the possibility of this thermal cycling.
It should also be noted that a separate internal thermal breaker also protects the power
transformer. If the power transformer temperature reaches a critical point, the internal thermal
breaker will open. The power LED on the front of the cabinet will go out and the VMAX will
shut down for several minutes while the power transformer cools. If this condition occurs,
simply reduce the signal level of the system. This will only occur if the VMAX is continually
pushed to the point of distortion.
NOTE: The power transformer inside the VMAX contains an enamel coating on the wires.
During the first several hours of heavy use, the VMAX may have a slight odor caused by the
enamel on the transformer wires heating.