Labgruppen lab 500 rev1 schematic

USER MANUAL HEADLINES

Unpacking 2

Warnings 2 User responsibility 2

1. Speaker damage

2. Speaker output hazard.

3. Radio interference.

Introduction 3

1. Front panel

2. Rear panel

Installation 4

1. Mounting

2. Cooling

3. Operating voltage

4. Grounding

5. Power consumption

6. Input connections

7. Connecting speakers

Operation modes 6

1. Stereo

2. Tandem mono

3. Bridged mono

4. Stereo reverse

Operation 7

1. Operation precautions

2. Input attenuators

3. Gain switch

4. Indicators

Protections 8

1. Clip-limiter

2. Thermal protection

3. VHF protection

4. Short circuit protection

5. D.C. protection

Unpacking

USER MANUAL

LAB 500

Design features 9

• Cooling

•

Safety approvals

• EMC approvals

Specifications 9

• EMC-declaration

Appendix A 10

• Mains voltage selection

Maintenance 10

Troubleshooting 10

Warranty and disclaimers 11

• General

• International

Technical assistance and services 11

• International

• Factory services

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, use the original packing.

Warnings

Read this before you are operating your amplifier:

• Do not use this amplifier if the power cord is

broken or frayed.

• Always operate the unit with the chassis

ground wire connected to the electrical safety earth.

• Do not parallel or series connect an amplifier

output, with any other amplifier 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.

• Do not run the output of any amplifier back

into another channel's input.

• Do not block the air intake or exhaust ports.

Do not operate the amplifier near heat producing devices such as radiators, stoves etc.

• Do not spill water or other liquids into or on

the unit. Do not operate the amplifier if suspected or standing in liquid.

• Do not remove top or bottom covers. Removal

of the cover will expose hazardous voltages. There is no serviceable parts inside and removal may void warranty.

• Keep this manual for future reference.

User responsibility

1. Speaker damage 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 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. Speaker output hazard Power amplifiers are capable of producing hazardous output voltages. To avoid electrical shock, do not touch any exposed speaker wiring, while the amplifier is operating. See page 6 about outputs for proper connection of speakers.

3. Radio interference

This product has been tested, and complies with the limits for the European Electro Magnetic Compatibility (EMC) directive. These limits are designed to provide reasonable protection against harmful interference between electrical equipment. However, there is no guarantee for no interference even if the amplifier is EMC approved. If the amplifier cause interference, which can be easily determined by turning the amplifier on and off, the user can correct the interference by one or more of the following steps:

1. Increase the proximity between the equipment.

2. Connect the AC cord to an outlet on a different

circuit from that to which the affected unit is connected.

3. If a radio receiver is interfered (normally

amplitude modulation); reorient the antenna.

4. Check if the affected unit complies with the

EMC limits for immunity, (CE-labelled).

If not, address the problem with the manufacturer or supplier. All electrical products sold in the EC must be approved for immunity against electromagnetic fields, high voltage flashes, and radio interference.

Introduction

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 yourself with the amplifier.

The front panel

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. If so desired they can be removed (by removing the screws behind the front panel) for fixed installations, or racks where the front covers are to shallow.

2. Input level attenuators

These controls are used to alter the signal level entering the amplifier. They are calibrated in dB to help set up active loudspeaker systems or cut down unwanted noise from the input signal. (See page 7).

3. Over temperature protect indicator. This indicator is lit if the amplifier tries to

operate above its maximum operating

temperature(90

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.

The rear panel

When the cooling fan have returned the output heat sinks to the normal operating temperature the input signal is unmuted.

4. VHF protection indicator

This indicator lights when constant signals, above 20 kHz at full power, are present at the output terminals. When this happens the input signal is muted and the process cycles until the VHF signal is no longer present. (See page 8).

5. Clip/limit indicator

This indicator tells when the amplifier output is clipping or limiting.

6. Fan grill filter. A foam filter is located behind the front panel to prevent dust entering the amplifier.

7. Power actuator

This is used to start the amplifier. (See page 4 and 7).

Figure 2. Rear panel

Please refer to diagram on page 3

1. Speaker connector

This type of speaker connector may be unfamiliar to some users. A full description is found in the operation section. (See page 6).

2. AC line cord (See page 5).

3. Input jack

Alternative to using input XLR or for linking inputs with other amplifiers. (See page 5).

4. Input signal XLR (See page 5).

Installation

1. Mounting

The amplifier is two rack units high (2U) and will mount in a standard EIA 19 inch rack. Amplifiers may be stacked directly on top of each other. There is no need for spacing between units. If it is the intention to fill a rack with amplifiers, we recommend racking is started from the bottom of the rack. It is also recommended that rear supports are used for amplifiers mounted in the middle of the rack, especially if used as part of a portable system.

2. Cooling

Your amplifier uses forced air cooling system to maintain a low and even operating temperature. All Lab.gruppen amplifier, which are fan ventilated, have front to rear cooling. There are several reasons for this, one is that there's usually cooler air outside the rack than inside and therefore the amplifiers can run at higher continuos power levels without thermal problems. Never try to reverse the air flow, as the Intercooler® need a pressure chamber between the fan and heat sink, and this only works in one direction of the air flow (see Design features on page 8). Should a heat sink get too hot, its sensing circuit will mute the hot channel. If the power supply overheats, another sensing circuit will mute all output channels, 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 with a dedicated rack room, it may be necessary to

5. Phase reverse switch for channel B

For reversing the input signal phase of channel B to allow bridged operation. (See page 7).

6. Link switch

Allows a single input to drive both channels simultaneously. (See page 7).

7. Gain select switch

Allows amplifier gain to be switched between 29dB and its normal gain at 0.775mV input sensitivity. (See page 7).

calculate the maximum heat emission. Refer to Power consumption on page 5.

3. Operating voltage

A label just below the mains cable on the rear of the amplifier indicates the AC mains voltage, for which the amplifier is wired. Connect the power cable only to the AC source referred to on the lab el. The warranty will not cover damage caused by connecting to the wrong type of AC mains. For converting a 230 volt amplifier to 115 volt or vice-versa, see Appendix A. The amplifier is supplied with an approved European AC line connector. If this connector is not appropriate for your country, it can be cut off and wired to a suitable connector in the following way :

BROWN LIVE

BLUE NEUTRAL

GREEN/YELLOW EARTH

Once the AC connector is connected to a suitable AC supply, the amplifier can be started with the AC actuator. When you power up the amplifier, the fan then blow at high speed before going onto "idle" and the 2 bottom green LED’s come on to show the output circuits are receiving the correct rail voltage.

4. Grounding

There is no ground lift switch or terminal on this amplifier. The signal ground is always floating via a resistor to chassis and the grounding system is automatic. If a potential above 0.6V presents itself between signal ground and chassis ground, a short circuit is introduced between the two, thereby enabling electrical protection. If a unit in the system is faulty, its mains fuse will blow, due to this automatic ground system.

+ 7 hidden pages