AtlasSound.com
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Specifications are subject to change without notice.
Owner’s Manual
MA40G / MA60G
Mixer Amplifier
1601 Jack McKay Blvd. • Ennis, Texas 75119 U.S.A.
Telephone: 800.876.3333 • Fax: 800.765.3435
Limit LED and Load Consideration
If the Red Limit LED illuminates, the amplifier has sensed an improper load or the input signal is too high, triggering the protection
circuitry. When the load sense Limit circuitry is engaged the amp will operate but at a lower power output. It is s highly recommended
to discontinue use immediately and correct the fault condition. If you continue to operate with the RED Limit LED on, the second stage
of the current sense circuit may engage causing the amp not to pass any signal. To reset the amp turn down the Level controls and turn
the power off for 10 seconds.
In most situations when the Limit LED is in the illuminated steady state it means the speaker system load to the amp is lower than
what the amp is rated. This usually is detected when the system is first set up. Below are a few load conditions to check for if the
Limit LED is on.
1. Connected to the wrong speaker terminal. Always check the speaker terminal to the type of load you are using. Example: If
you are installing a 70V or 100V system make sure the wires are connected to the 70V/100V and common (COM) terminals.
2. Too many speakers connected to the amp. This is a very common mistake. If you are using a 60W amp and using the 70V
speaker terminals, add up the number of speakers and their wattage selections at the speaker. If they exceed 60W you must
retap the speakers or remove the correct amount of speaker wattage until the wattage is 60W or less. Example if you are
using a 30W tap you can only connect 2 speakers to the amp. If you are using the 7.5W tap, you can connect 8 speakers. If
you have too many speakers on the amp it will load the amp down, causing excessive current demand and will trigger the
Limit & Protect circuit.
3. Wrong speaker tap selection. It is also common in a 70V or 100V system that one of the speakers is set at too low of an
impedance (8ohm) and not a 70v or 100v tap. Note: It only takes one speaker to load the amp down incorrectly.
4. Short in system. This is common if the wire is run in metal conduit and the wire got nicked during the wire pull.
5. Speaker Level Controls. If an L-PAD or stepped attenuator is wired wrong it can also load a system down.
Measuring Speaker Loads
Below is an Impedance load chart for the MA40G and MA60G. Measure the load impedance prior to connecting the load to the
amplifier. The enclosed load chart will provide the information to determine if the load or speaker system impedance is too low for the
amplifier's rating. In every install it is always recommended to measure the load prior to turning the system on to be sure the system
is installed correctly.
MA40G & MA60G Max Load Chart
Speaker
Selection
MA40G
MA60G
70.7V
100V
125 Ohms
166 Ohms
250 Ohms
83 Ohms