Operating Manual - nX, nXe, and nXp Power Amplifiers
10
3 nX AMPLIFIER PROTECTION
Power-On Delay
-All models have a fixed and undefeatable warm-up delay of three seconds when first powered on or
awakened from sleep. This is necessary to prevent excessive in-rush current during start-up. Additionally, nXe and nXp amplifiers
have programmable Power-On Delay ranging from zero to 25 seconds in 100ms increments
(see section 9.2)
.
Thermal Protection
- Cooling fans are continuously variable, increasing in speed as the amp heats up. The fans are at their
maximum speed when an amplifier channel reaches 80% of it's safe operating temperature, and the Temp LED also turns on. At
90%, the Protect LED turns on to indicate that countermeasures are being applied to attenuate the input signal to the overheating
channel. A Temp LED turns on dim at first, then increases in brightness as the amp channel approaches maximum safe temperature.
100% critical temperature will shut down the amplifer.
Overpower Protection
- To protect internal components against overpower conditions, a protection scheme in each output
stage reduces audio output power until the fault condition is no longer present.
Output DC and Rail Fault Protection
– Output DC on any channel will trigger the Protect LED and mute that channel.
Voltage rail irregularities such as power supply pumping are also detected and compensated for in real time as the amp runs.
For more details of these protection schemes and indicators, see
Troubleshooting
in section 14.
4 nX FRONT PANEL FEATURES (all models)
4.1 Mounting Holes
– For mounting to a 19" equipment rack.
4.2 Air Vents
– Cool air enters in through the amplifier sides and is vented out the front.
4.3 Factory Reset/Sleep Mode/Disable Switch
– This recessed switch is used to perform a factory reset. It is also
used to set sleep mode and front panel disable status (see below). To perform a factory reset and return all amplifier settings to
their original factory defaults (without erasing presets) use a pencil point or equivalent to press and hold the switch
during power
up
until all channel LEDs sequence from bottom to top. Releasing the switch before the LED sequence is complete will cancel
the process. Upon completion, all LEDs turn off and the amplifier resumes normal operation.
Setting Sleep and Front Panel Disable Mode -
The factory reset switch is also used to
select one of four sleep and front-panel-control-disable modes as illustrated to the right. The
default status is Sleep and Disable OFF (
Mode 1
). To advance to the next mode, press and
hold this switch when the amplifier is fully on, and the four mode combinations will cycle
and repeat
.
To select a mode, simply release the switch when the desired mode is displayed.
The Disable LED is lit any time the front panel controls are disabled, either by selecting
disable mode from this switch or using software control.
The sleep LED turns on during the mode-select cycle whenever sleep mode is enabled,
but turns back off as soon as the switch is released, remaining off unless the amp actually goes
to sleep. The current sleep mode status can be displayed when the amp is fully on by quickly
pressing and releasing the reset switch. If the sleep LED lights, sleep mode is active.
