Front Panel - Phonic MAX 250 User Manual

FRONT PANEL

1. Gain Controls
These two knobs are the level controls for Channel one and two
respectively. Turning clockwise will increase its gain, and counter-
clockwise will decrease its gain. Please always power-up with the
volume all the way down, and increase volume slowly to make
sure that no conditions exist which could annoy your audience or
harm your speakers
2. Protect LED Indicator (MAX500 only)
The MAX500 features several types of protection to prevent
damage to the circuitry during turn-on or fault conditions. If the
LEDs light up, this indicates that one of the various protections is
safeguarding the different sections of the amplifier and in these
cases, the power output is normally switched off until normal
operating conditions are restored.
 Loudspeaker protection: in the event of malfunction, a sensor
located on the power outputs is able to break the circuit
avoiding that current peaks reach the speakers and damage
them.
 Thermal protection on the heatsink: If the amp overheats,
thermal shutdown protects the circuitry until the temperature
is reduced to a safe level.
 Short circuit protection: The Protect LED Indicator will also
light up if the speaker terminals are short circuited, or the
impedance of the load is too low. In these circumstances, the
Protect LED will stay on until the fault condition is rectified.
Some protection situations require the amplifier to be
switched off and then back on for normal operating conditions
to be restored.
2
3. Limit/Clip Indicator
This LED lights up during clipping status, whenever any conditions
occur that could leak to non-linearility, such as an out-of-spec
load and waveform distortion. Because of the MAX's ability to
enter and exit clipping with as few audible artifacts as possible,
you may not hear any distortion even if the indicator flashes. In
general, a few flashes every now and then will not be a problem.
However, if the LEDs flash often or remain on for any extended
period of time, then turn the volume controls down to reduce the
signal level going into the MAX. If this doesn't solve the problem,
check your output cables and speakers.
4. Signal Indicator
Each channel of the MAX features a signal LED to show that there
is an audio signal at the input to the channel. The threshold for
the indicator is -26 dB, which should be enough to avoid noise
triggering the LED.
5. Power Switch and Indicator
This is the power on/off switch with an LED indicator.
Always start with Gain Control (1) all the way down before
powering-up to avoid abnormal sound from defective cables
or hookups.
MAX250 / MAX500