Labgruppen fp3400 115 schematic

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1 CONTENTS .......................................................................................................................................1

2 APPROVALS.....................................................................................................................................2

3 WARNINGS ......................................................................................................................................2

3.1 Explanation of graphical symbols ..............................................................................................2

3.2 WARNING.................................................................................................................................2

3.3 CAUTION ..................................................................................................................................2

3.4 Important Safety Instructions .....................................................................................................2

3.5 User responsibility......................................................................................................................3

3.5.1 Speaker damage..................................................................................................................3

3.5.2 Speaker output hazard ........................................................................................................3

3.5.3 Radio interference ..............................................................................................................3

4 INTRODUCTION..............................................................................................................................4

4.1 Unpacking ..................................................................................................................................4

4.2 Front Panel .................................................................................................................................4

4.3 Rear Panel...................................................................................................................................5

5 REAR PANEL FEATURES ..............................................................................................................6

5.1 Gain switch.................................................................................................................................6

5.1.1 The DIP-switch...................................................................................................................6

5.1.2 Sensitivity...............................................................................................................................6

5.1.3 Options ...............................................................................................................................6

5.2 Link switch .................................................................................................................................6

5.3 Operation modes.........................................................................................................................7

5.3.1 Stereo mode............................................................................................................................7

5.3.2 Note for bench test .............................................................................................................7

5.3.3 Tandem mode.....................................................................................................................7

5.3.4 Bridge mono mode .............................................................................................................7

5.3.5 Bridge mono mode features................................................................................................8

5.4 Impedance matching (MLS switch) ...........................................................................................8

5.4.1 A practical way to find your MLSTM settings.....................................................................9

5.4.2 MLS technology – the background ..................................................................................10

5.4.3 The problem .....................................................................................................................10

5.4.4 The solution......................................................................................................................10

6 INSTALLATION.............................................................................................................................10

6.1 Mounting ..................................................................................................................................10

6.2 Cooling .....................................................................................................................................10

6.3 Operating voltage .....................................................................................................................11

6.4 Grounding.................................................................................................................................11

6.5 Power consumption ..................................................................................................................11

6.5.1 Calculation........................................................................................................................12

7 CONNECTIONS..............................................................................................................................13

7.1 Input connections .....................................................................................................................13

7.1.1 Balanced inputs ................................................................................................................13

7.1.2 Unbalanced inputs ............................................................................................................13

7.2 Connecting speakers.................................................................................................................14

8 OPERATION ...................................................................................................................................14

8.1 Operation precautions...............................................................................................................14

8.2 Powering up – Soft start ...........................................................................................................14

8.3 Input attenuators .......................................................................................................................15

8.4 Indicators..................................................................................................................................15

9 PROTECTION FEATURES............................................................................................................15

9.1.1 Clip limiter .......................................................................................................................15

9.1.2 Thermal protection ...........................................................................................................16

9.1.3 VHF protection.................................................................................................................16

9.1.4 Short circuit protection.....................................................................................................16

9.1.5 AC mains voltage protection ............................................................................................16

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9.1.6 DC protection ...................................................................................................................16

10 MAINTENANCE.........................................................................................................................17

10.1 Troubleshooting........................................................................................................................17

11 SPECIFICATIONS ......................................................................................................................18

12 WARRANTY...............................................................................................................................19

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This equipment is tested and a
the U.S. safety standard ANSI/ UL 6500 and
Canadian safety standard CSA E60065-00. ET
the tests and they are a Nationally Recognized Testing
Laboratory (NRTL).
The ETL Listed Mark

inspectors and Authorities Having Jurisdiction
throughout North America and also in some areas of South America. ITS ETL SEMKO is a NRTL
recognized by OSHA (Occupational Safety and Health Administration
accepted alternative to UL and, as such, inspectors and AHJs are required by law to recognize,
acknowledge, and accept the mark as proof of product compliance. See more on ETL Web:

www.etlsemko.com/S1OurMarks/index.htm

pproved according to

L made

is recognized by local

(AHJs)

), the ETL Listed Mark is an

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The lightning symbol within a triangle is

intended to alert the user to the
presence of un-insulated “dangerous voltage”
within the amplifier’s enclosure that may be of
sufficient magnitude to constitute a risk of
electric shock to humans.

The exclamation point within a triangle is

!

intended to alert the user to presence of
important operating and service instructions in
the literature accompanying the product.

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To reduce risk of fire or electric shock, do not
expose this apparatus to rain or moisture.

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To reduce the risk of fire or electric shock, do
not remove screws. No user-serviceable parts
inside. Refer servicing to qualified service
personnel.

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Before using your amplifier, be sure to carefully read the applicable items of these operating
instructions and the safety suggestions

1. Keep this manual for future reference.

2. Heed all warnings.

3. Follow all instructions.

4. Do not use this unit near water. Do not spill water or other liquids into or on the unit. Do not
operate the amplifier while wet or standing in liquid.

5. Clean only with dry cloth.

6. Do not block the air intake or exhaust ports. Install the unit in accordance with the instructions.

!

7. Do not operate the amplifier near heat producing devices such as radiators, heat registers, stoves
or other apparatus that produce heat.

8. Always operate the unit with the chassis ground wire connected to the electrical safety earth. Do
not defeat the safety purpose of a grounding-type plug. A grounding type plug has two pins and
a third grounding prong. The third prong is provided for your safety. If the provided plug does
not fit into your outlet, consult an electrician for replacement of the obsolete outlet.

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9. Connect only to AC power outlets rated 100-120V, 50-60Hz.

10. Do not use this amplifier if the power cord is broken or frayed. Protect the power cord from
being walked upon or pinched particularly at the plugs and the point where it exits from the
apparatus.

11. Only use accessories specified by the manufacturer.

12. The unit is intended to use in a 19” rack. Follow the mounting instructions. When a rack on

!

wheels is used, use caution when moving the loaded rack to avoid injury from tipping over.

13. Unplug this apparatus during lightning storms or when unused for long periods of time.

14. Do not connect an amplifier output in parallel or series with any other amplifier’s output. Do
not connect the amplifier output to any other voltage source, such as battery, mains source, or
power supply, regardless of whether the amplifier is turned on or off.

15. Do not run the output of any amplifier back into another channel's input.

16. Refer all servicing to qualified service personnel. Servicing is required when the apparatus has
been damaged in any way such as:

• Power-supply cord or plug is damaged

• Liquid has been spilled into the unit

• An object has fallen into the unit

• The unit has been exposed to rain or moisture

• The unit does not operate normally

• The unit was dropped or the enclosure is damaged

17. Do not remove top or bottom covers. Removal of the cover will expose hazardous voltages.
There are no serviceable parts inside and removal may void the warranty.

18. An experienced user shall always supervise this professional audio equipment, especially if
inexperienced adults or minors are using the equipment.

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Your amplifier is very powerful and can be potentially dangerous to both, 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 amplifier’s front panel attenuators can be used to reduce the gain, it is still possible to reach
full output power if the input signal level is high enough.

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Power amplifiers are capable of producing hazardous output voltages. To avoid electrical s
do not touch any exposed speaker wiring while the amplifier is operating. See page 14
outputs for proper connection of speakers.

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This equipment has been tested and found to comply with the limits for a Class B digital device,
pursuant to Part 15 of the FCC Rules. These limits are designed to provide reasonable protection against
harmful interference from electrical equipment. This product uses radio frequency energy and if not
used or installed in accordance with these operating instructions, may cause interference to other
equipment, such as radio receivers. However, there is no guarantee that interference will not occur in a
particular installation.
If this equipment does cause harmful interference to radio or television reception, which can be
determined by turning the equipment on and off, the user is encouraged to try to correct the interference
by one or more of the following measures:

• Reorient or relocate the antenna.

• Increase the separation between the equipment and receiver.

• Connect the equipment into an outlet on a circuit different from that to which the receiver is

connected.

• Consult the dealer or an experienced radio/TV technician for help.

hock,

about

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Thank you for purchasing a Lab.gruppen power amplifier. This manual contains important information
on operating your amplifier correctly and safely. Please take some time and read this manual to
familiarize you with the advanced features of this amplifier.

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Carefully open the shipping carton and check for any noticeable damage. Every Lab.gruppen amplifier
is tested and inspected before leaving the factory and should arrive in perfect condition. If found to be
damaged, notify the shipping company immediately. Only the consignee may institute a claim with the
carrier for damage incurred during shipping. Be sure to save the carton and packing materials for the
carrier's inspection.
It is also advisable to save the carton and packing material, even if the amplifier is undamaged. Should
you ever need to ship the amplifier, always use the original packing.

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Figure 1: Front panel

1. Carry/protection handle

Both handles can be used to carry the amplifier; they also act as protection for the front panel. In
permanent installations, or where rack front covers are too shallow they may be removed by unscrewing
the retaining bolts behind the front panel.

2. Input level attenuators

These controls are used to alter the signal level entering the amplifier. They are calibrated in dB to assist
the setup of active loudspeaker systems, or to cut down unwanted noise from the input signal. (See page

15

)

3. Over temperature protect indicator

This indicator illuminates if the amplifier is going to operate above its maximum operating temperature

°

C). The indicator first comes on as a warning to either turn down the input level or check the

(90°
cooling arrangements. Beyond the maximum temperature the amplifier will mute the input signal. Once
the cooling fans have brought the output heat sinks back to normal operating temperature the input
signal is un-muted.

4. VHF protect indicator

This indicator illuminates if signals above 12 kHz are continuously present at full power at the output
terminals. If this occurs the input signal is muted, and the process cycles until the VHF signal is no longer
present. (See page 16

)

5. Clip/limit indicator

This indicator signals if the amplifier output is clipping or limiting. It has two different indication states:
If the clip limiter is engaged, it has a short time constant, and it illuminates briefly.
If the clip limiter is not engaged, it has an increased time constant, and it illuminates for a longer period.
(See page 15

)

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6. Fan grill filters

Two grilles with foam filters are located on the front panel to prevent dust from entering the amplifier. For
easy cleaning of the filters the grilles are removable by simply pulling them off. The foam filters should
always be used.

7. Power switch

Turns mains power on or off. (See page 11

and 14)

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Figure 2: Rear panel

1. Output / Speaker connector

The Speakon connector from Neutrik® may be unfamiliar to some users. A full description can be found
in the “Connections” section. (See page 14

)

2. Minimum load selector (MLS™) switch

These switches are used to select the maximum output power. (See page 8

)

3. Clip limiter switch

Turns the clip limiter on or off. (See page 15

)

4. Input signal XLR.
Neutrik® Combojack features also ¼” TRS phone jacks. (Pin 2 is “hot”, see page 13

)

5. Link output
XLR male connector connected in parallel to the female for linking the channel to another input.

6. Gain switch channel B
Three of the switches in the DIP switch selects the maximum gain of the channel to be either 20, 23, 26,
29, 32, 35, 38 or 41dB. (See page 6

)

7. Link/Bridge switch
Two of the switches in the DIP switch are used for Link and Bridge operation. (See page 6

)

8. Gain switch channel A
Three of the switches in the DIP switch selects the maximum gain of the channel to be either 20, 23, 26,
29, 32, 35, 38 or 41dB. (See page 6

)

9. AC power cable

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