Lab Gruppen 1200c 4ch Amplifier

FEATURES

• 4x370 W into 8 ohms 4x380 W into 4 ohms at clip level with four channels driven

• Low weight

• MLS switch offers full power in 8 or 4 ohms without increased power losses

• Electronically balanced inputs

• LED indicators show output voltage and headroom

• Independent protection circuitry

• ALSTM short circuit protection manages long-term shortcircuit operations

• VHF protection

• DC protection

• Output cooled by Intercooler®

• Two proportional speed fans

• Clip limiter

The LAB 1200C gives the opportunity of use in several applications, such as; in multi-channel monitor systems, fourchannel reproduction, and compact amplification in active 2-, 3-, and 4-way systems.

The LAB 1200C gives the possibility to bridge connect one or two of the two pair of channels (channel A and B and/ or channel C and D). These bridge mode combinations solve most of the problems concerning different impedance’s and maximum power handing of loudspeakers.

The switch-mode power supply is the modern solution of the weight and size problem. With switch technology operating at a high frequency, it is possible to use ferrite transformers instead of heavy iron transformers and large electrolytic capacitors.

Switch-mode technology has been applied in power supplies in TV-sets during the latest 30 years. But in the LAB 1200C the power capacitivity is 10 times larger.

We have designed the LAB 1200C to obtain the same characteristics as a conventional power supply. Thanks to the switch-mode power supply it is easy to get the DC-rail voltage stabilised. This is made by controlling the magnetic energy in the ferrite transformer with a pulse width processor and magnetic “Flux Sense” windings.

Twenty-four 250 watt bipolar power transistors constitute the output stages, which are totally complimentary. The power transistors are cooled by a solid copper cooler, called Intercooler®, originally designed for our LAB 1300 power amplifier. LAB. GRUPPEN’s specially designed thermal feedback circuit protects against thermal breakdown.

The LAB 1200C is completely shortcircuit protected . The LAB 1200C is equipped with LAB. GRUPPEN’s Adaptive Limiting SystemTM short circuit protection, which permits very high peak-currents, but still holds the transistors within the so-called “Safe Operation Area” at the present operating voltage. This makes it possible to run loudspeakers with impedance variations, which are considerably lower than the lowest permitted impedance of the power amplifier.

Six more protection circuits, which are separate for each channel, protect the LAB 1200C and the loudspeakers:

Two DC protections; one DC current limitation protection, supplemented with fuses on each DC voltage power supply rail; and one DC voltage protection of Crowbar type, which works by short-circuiting the output to protect the load.

Thermal protection; prevents the LAB 1200C from being overheated. The protection indicators on the front panel are switched on, as a warning, before the protection occurs.

VHF protection (Very High Frequency); protects the loudspeakers against strong non-musical signals above the audible area.

Clip limiter; prevents severely clipped waveforms from reaching the loudspeakers, but maintains full peak power.

AC protection; shuts down the outputs if the line voltage is outside the operating voltage of the LAB 1200C.