JBL MP418SP - Manual (Page 10)

CONTROLS AND CONNECTORS
10
1. Int and Ext Level Controls: Sets the volume of the associated amplifier channels. The Int
Level Control adjusts the volume of the MP418SP internal speaker. The Ext Level Control
adjusts the volume of the speaker connected to the External Speaker Connector.
2. Int and Ext Fault Indicators: Two red LEDs (one for each channel) are located on the
panel. Some fault conditions may cause the output of the amplifier to be muted. The Fault
Indicators are normally OFF, but will blink under five different conditions:
* When the amplifier is first powered up, until the unit is ready for operation.
* If the heatsinks reach a temperature above normal working limits.
* If the transformer thermal protection circuit is activated.
* If amplifier output wires develop a short-circuit.
* Should the amplifier output stage become non-operational.
3. Int and Ext Clip Indicators: Two red LEDs (one for each channel) are located on the
front panel. The Clip indicators turn on when distortion is audible in the amplifier output.
4. Int and Ext Signal Indicators: Two green LEDs (one for each channel) illuminate when a
signal is present at the INPUT of that channel.
5. Ext Channel Input: This input is summed with the Int Channel Input and sent to the
amplifier’s Low Pass Filter.
* In the Sub + Sat mode, this input is also connected directly to the Ext Out connector.
* In the Sub + Sub mode, this input is also routed through a High Pass Filter and then
to the Ext Out connector.
6. Int Channel Input: This input is summed with the Ext Channel Input and sent to the
amplifier’s Low Pass Filter.
* In the Sub + Sat mode, this input is also connected directly to the Int Out connector.
* In the Sub + Sub mode, this input is also routed through a High Pass Filter and then
to the Int Out connector.
7. Sub + Sat / Sub + Sub Selector: Selects the mode of operation
* Sub + Sat Mode: The Internal Channel drives the MP418SP internal speaker. The
External Channel is fed from a High Pass Filter and should be used to drive a full-
range external speaker.
* Sub + Sub Mode: The Internal Channel drives the MP418SP internal speaker. The
External Channel is fed from a Low Pass Filter and should be used to drive a JBL
MP418S non-powered subwoofer.
8. Polarity: Sets the polarity of the MP418SP internal subwoofer.
9. Int Thru / High Pass Out: See items 5 thru 7 above.
10. Ext Thru / High Pass Out: See items 5 thru 7 above.
11. External Speaker Output: This Speakon NL-4 connector connects the External Amplifier
Channel to an external speaker.
12. Power Indicator: The Power Indicator lights when your MP418SP amp has been turned
on and has power.
13. Power Switch: The power turns the amplifier on. When the switch is depressed left,the
amp is off.
14. IEC Power Cord Connector: For attachment of the included Power Cable.
15. Reset Switch: Used to reset the circuit breaker that protects the power supply.
(Refer to Panel Call Out Drawing on page 14)