The Led Meters And Fault Conditions - D'Amore Engineering A1500.2 Owner's Manual

The LED meters (cont.)
Our meters are calibrated in 3dB steps with the final
RED segment indicating the output is near or at clipping.
As such in normal use it is okay for the meters to flash
red on occasion but if they are solid RED for any length
of time the output is probably clipping and the output
level should be reduced to avoid speaker damage.

The LED Meters and fault conditions

Since our meters require some brains to run them (we
are using an Atmel ATMEGA microprocessor) we
decided to make them do some other useful things as
well. Meter special functions listed below.
st
Blue, 1 segment illuminated = Power On, condition
normal.
Blue, 1st segment blinking on and off = Low B+
Protection. This indicates that the battery voltage level
dropped below 9.5 Volts DC during use. The amplifier
will mute and flash the first segment of the meter for
approximately 10-15 seconds after which the amplifier
will unmute and continue provided the B+ is above 9.5V
th
Amber, 10 segment blinking on and off = Thermal
protection. This indicates that the temperature of one or
more of the heatsinks has exceeded 85C (185F). This is
still within safe operating parameters for the amplifier but
since the heatsinks are exposed we chose to shut the
amplifier down if this temperature is exceeded. Once
the temperature is below 78C (172F) normal operation
will resume.
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