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Never connect either output terminal to ground 
or in parallel

. The recommended minimum 

nominal impedance, for stereo or tandem operation, 
is 2 ohms per channel. 

 

2.  

Tandem mono 

For tandem ( dual channel-single input) operation , 
depress the Link switch. Both channels can now be 
driven by a signal, at either input connector. The 
output connection is the same as in stereo mode. 
You can use either TRS connectors for linking out 
etc

. Do not use the remaining XLR and TRS 

connectors for mixing or other purposes.

 Both 

level attenuators are active, allowing you to set 
different levels for each channel. 

Never connect either output terminal to ground 
or in parallel. 
 

3.  

Bridged mono 

To bridge the amplifier, depress the Link switch (6) 
and Phase reverse switch (5). Both channels are then 
driven by a single signal at either input. You can 
use any remaining input connectors for linking etc. 
Do not use the remaining XLR and TRS as input 
jacks simultaneously for mixing or other purposes. 
To obtain an output, connect the speaker leads to 

pin 

+1 on channel A Speakon to speaker positive 
terminal and pin +1 on channel B Speakon to 
speaker negative terminal .  Do not connect either 
of the -1 (negative) pins of the Speakons.

 

 Do not  

connect speakers to channel A or B in the normal 
manner

 

in bridge mode, as this can cause serious 

damage

.  

The recommended minimum nominal impedance 
for bridged mono is 4 ohms (equivalent to driving 
both channels at 2 ohms).  
Driving bridged loads of less than 4 ohms may cause 
a thermal overload. 
 

 

 

Figure 10. Bridge mono connection 
 

Both level attenuators must be at the same position. 
We recommend you to put them in the 0 dB (full) 
position. 

 
4.   Stereo reverse 

This mode is similar to the Tandem mono mode. 
Apart from depressing the Link switch , you also 
depress the Phase reverse switch, like in the Bridge 
mono. Channel B is now phase reversed. To 
compensate for that, connect 

pin +1 on channel B 

Speakon to speaker negative terminal and pin -1 
on channel B to speaker positive terminal

 

Figure 11. Stereo reverse mode 

 
Channel A output is connected as in the normal 
stereo mode. By having channel A and B operating 
in opposite polarity, the energy storage in the 
power supply is more efficient. This means that the 
amplifier can deliver up to 10% more power than in 
tandem mono mode. This is significant for signals 
below 100 Hz (sub bass etc.). 
 
 

 
Operation 

1. Operation 

precautions 

• 

Make sure that the power switch is off before 
making any input or output connections or 
operating the switches on rear panel. See pages 
4-6 about installation.

 

• 

Make sure that the AC mains is correct and the 
same as that is printed on the rear panel of the 
amplifier. See pages 4-5 , about operating 
voltage and power consumption.

 

 

 

• 

Make sure that the switches on the rear panel 
for operation modes ,clip limiters, etc. are in 
the correct position. See pages 6-7, about 
operation modes and page 8 about clip limiters.

 

• 

It is always a good idea to turn down the gain 
controls during power up, to prevent speaker 
damage, if there is a high signal level at the 
input. 

 
 
 
 
2.     Powering up -Soft start 

 

7

Summary of Contents for LAB 1300C

Page 1: ...on 7 1 Operation precautions 2 Powering up Soft start 3 Input attenuators 4 Gain switch 5 Indicators Protections 8 1 Clip limiter 2 Thermal protection 3 VHF protection 4 Short circuit protection 5 AC mains voltage protection 6 D C protection LAB 1300C USER MANUAL Design features 9 Cooling Light weight Regulated power supply Safety approvals EMC approvals Specifications 10 EMC declaration Appendix ...

Page 2: ...oth loudspeakers and humans alike Many loudspeakers can be easily damaged or destroyed by overpowering especially with the high power available from a bridged amplifier Always check the speakers continuous and peak power capabilities Even if the gain is reduced by using the amplifier s front panel attenuator it is still possible to reach full output power if the input signal level is high enough 2...

Page 3: ...ate above its maximum operating temperature 90o C The indicator first comes on as a warning to either turn down the input level or check the cooling arrangements after which point the amplifier will mute the input signal When the cooling fans have returned the output heat sinks to the normal operating temperature the input signal is unmuted 4 VHF protection indicator This indicator lights when con...

Page 4: ...until it cools down to a safe operating temperature Make sure that there is an adequate air supply in front of the amplifier and that the rear of the amplifier has sufficient space to allows the exhaust to escape If the amplifier is rack mounted do not use covers or doors on the front or rear of the rack For fixed installations with a central cooling system usually found in fixed installations wit...

Page 5: ...h of the total power is as loud as you can play music while making some attempt to avoid obvious clipping It also corresponds to a headroom of 9dB which is very low for an audio program In 2 ohms operation the protection of the amplifier circuit will not permit long term current draw and the component temperature rise will stabilises well below the rating MAX OUTPUT POWER MAINS INPUT POWER Power F...

Page 6: ...e two Neutrik NL4FC Speakon connectors 1 They are the only connectors currently available to meet the EC safety requirements They are wired in the following manner Pin 1 Speaker ground Pin 1 Speaker positive Pin 2 No connection Pin 2 No connection Figure 9 Speakon connector Please note that this is the standard wiring convention for Speakon connectors adopted world wide Never connect either output...

Page 7: ...hms Driving bridged loads of less than 4 ohms may cause a thermal overload Figure 10 Bridge mono connection Both level attenuators must be at the same position We recommend you to put them in the 0 dB full position 4 Stereo reverse This mode is similar to the Tandem mono mode Apart from depressing the Link switch you also depress the Phase reverse switch like in the Bridge mono Channel B is now ph...

Page 8: ...below Protection features Each LAB GRUPPEN amplifier has many advanced protection features that will protect both the amplifier and the speakers connected to it should a fault condition arise Under normal use these features are inaudible All protection circuits are independent Clip limiter The clip limiter is included to prevent dangerous clip signals reaching the speaker and damaging it It works ...

Page 9: ...a pressure chamber The air flow is constant along the whole heat sink thanks to a horizontal pressure chamber in front of it in a conventional tunnel design the end of the heat sink opposite to the fan invariably gets hotter than that directly in front of the fan When cool air hits the geometric fins of the IntercoolerTM turbulence is produced thereby enabling efficient cooling Light weight The sw...

Page 10: ...Immunity The equipment should be able to handle three different types of interference Electrostatic discharges up to 8 kV hitting the chassis or cables Transients and bursts up to 1 kV conducted through the cables to the unit Electromagnetic fields up to 3 V m radiated on the unit and the cables in the frequency range of 27 500 MHz We have extended the tests in two cases and chosen a standard used...

Page 11: ...nside of the amplifier These conditions usually occur after prolonged use in environments using cracked oil smoke machines If you are using your amplifier for heavy duty use i e concert touring or industrial music it is recommended that you have your amplifier serviced every 3 years purely as a preventative measure Troubleshooting These are typical things to check if you think your amplifier is fa...

Page 12: ...e 3 LAB GRUPPEN shall not be responsible for any incidental or consequential damages with respect to the products warranted LAB GRUPPEN reserve the right to make changes or improvements in design or manufacturing without assuming any obligation to change or improve products previously manufactured International Please contact your supplier for this information as rights and disclaimers may vary fr...

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