JB Systems amp 150.4 Mode D'emploi page 5

ENGLISH
CONNECTIONS
Be sure to turn off the unit before you make changes to the wiring. Use good quality signal cables to ensure
excellent audio quality. For example use JB cables with order codes: 7-0061 (XLR/XLR L=1m) or 7-0063
(XLR/XLR L=5m). For the speakers we suggest using the Speakon
for example JB order codes: 2-0505 (L=5m) or 2-0510 (L=10m).
FUNCTIONS (FRONT)
This amplifier has 2 totally independent stereo amplifiers inside: amplifier 1 serves channels 1+2, amplifier 2
serves channels 3+4. Both amplifiers can be used in a different working mode (stereo, parallel or bridge)
which gives you more flexibility. Refer to the chapter "HOW TO USE" for more information.
1. POWER LED: This white led is on when you turn the amplifier on using switch(2).
2. MAINS SWITCH: Used to turn the amplifier on and off. A few seconds after switching on the amplifier it
is ready for operation.
3. GAIN CONTROL CH1: used to control the input sensitivity of amplifier channel1. Use this input when
amplifier 1 is set to parallel or bridge mode.
4. GAIN CONTROL CH2: used to control the input sensitivity of amplifier channel2. This input is NOT used
when amplifier 1 is set to parallel or bridge mode.
5. GAIN CONTROL CH3: used to control the input sensitivity of amplifier channel3. Use this input when
amplifier 2 is set to parallel or bridge mode.
6. GAIN CONTROL CH4: used to control the input sensitivity of amplifier channel4. This input is NOT used
when amplifier 2 is set to parallel or bridge mode.
7. SIGNAL LEDS: these LEDs indicate that a music signal is present at the inputs.
8. CLIP LEDS: Lit just before the maximum, distortion free, output level of the amplifier. They indicate that
the internal limiter starts working. The clip LEDs may turn on shortly from time to time but they may
certainly not turn on for longer periods. In this case you have to turn the output level down!
9. AUDIO PROTECT LED: is on when the speakers are disconnected from the amplifier. This occurs in the
following situations:
 During the first seconds after switching on the amplifier.
 When the temperature of the power stage becomes too high.
 In case of a technical defect: DC protection, overload, short circuit, ...
 While switching the amplifier off, the "protect led" turns on for a short time.
FUNCTIONS (rear)
10. OPERATION MODE switch: Used to set the operation mode of amplifier 1 (CH1+2):
 STEREO: The most common operation mode, CH1+2 are routed to their corresponding outputs.
 PARALLEL: only the mono signal on input channel1 (11) is used to drive both outputs CH1+2.
 BRIDGE: used when you need more power. Only the mono signal on input channel1 (11) is used
to drive the combined "bridged" output. Only speakers with impedance >8ohm are allowed.
11. XLR input CH1: you can connect a balanced or unbalanced signal, both XLR and ¼" jacks can be used.
12. XLR input CH2: you can connect a balanced or unbalanced signal, both XLR and ¼" jacks can be used.
Only used while amplifier 1 works in stereo mode (10).
13. BINDING POST output CH1: use this output when the speaker cable has no Speakon connector.
JB SYSTEMS
®
®
compatible outputs. Suitable cables are
3/34
USER MANUAL
AMP 150.4