Lab.gruppen LAB 1000 User manual

POWER AMPLIFIER
100
0
FEATURES
◆ 2 x 350 W into 8 Ω
2 x 550 W into 4 Ω
2 x 675 W into 2 Ω
at clip level with both
channels driven
◆ Compact design, 2 U high
(88 mm)
◆ Low weight
◆ Electronically balanced
inputs
◆ LED indicators show output
voltage and headroom
◆ Independent protection
circuitry
◆ Manages long-term short-
circuit operations
◆ VHF protection
◆ DC protection
◆ Output cooled by Intercooler
®
◆ Two proportional speed fans
◆ Clip limiter
LAB. GRUPPEN’s LAB 1000 is a high
power amplifier, designed for 19”
rack mounting.
The 2 U (units) high welded chassis
is made of 2 mm thick steel plate.
The power transformer is of a two-
coil low-loss type, mounted just be-
hind the front panel, which gives the
LAB 1000 a stable and balanced de-
sign. Both the power supply and the
two output channels are cooled by
two proportional speed fans, where
the air flows from front to back.
Twenty 250 watt bipolar power
transistors constitute the output
stages, which are totally complimen-
tary. The power transistors are
cooled by a solid copper cooler, called
Intercooler(r), originally designed for
our SS 1300 power amplifier. LAB.
GRUPPEN’s specially designed ther-
mal feedback circuit protects against
thermal breakdown.
The output stage is designed total-
ly discreet, to get the best optimisa-
tion for linearity and bandwidth. The
driver stage consists of an “enhanced
cascode circuit”, which is differential
symmetrical in class A, to achieve low
distortion at high frequencies. The
circuit was originally developed by
LAB. GRUPPEN in 1980, and experi-
ence has proven that this design gives
the power amplifier high reliability.
The LAB 1000 is completely short-
circuit protected - even in reactive
loads. The LAB 1000 is equipped
with LAB. GRUPPEN’s specially de-
signed short circuit protection, which
permits very high peak-currents, but
still holds the transistors within the
so-called “Safe Operation Area”. This
makes it possible to run loudspeakers
with impedance variations, which are
considerably lower than the lowest
permitted impedance of the power
amplifier.
Four more protection circuits,
which are separate for each channel,
protect the LAB 1000 and the loud-
speakers:
Two DC protections; one DC cur-
rent limitation protection, supple-
mented with fuses on each DC volt-
age 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 1000 from being overheated.
The temperature indicators on the
front panel are switched on, as a
warning, before the protection oc-
curs.
VHF protection (Very High Fre-
quency); protects the loudspeakers
against strong non-musical signals
above the audible area.
Clip limiter; prevents severely
clipped waveformss from reaching
the loud-
speakers, but maintains full peak
power.
All electronics are mounted on two
modules, one for channel A and one
for channel B. The modules are easily
accessible for replacement or repair,
etc.

SPECIFICATION
1000
Lab.gruppen AB, Gullregnsvägen 16, SE-434 44 Kungsbacka, Sweden.
Tel. [phone]. Fax [phone]. www.labgruppen.se
LAB. GRUPPEN reserve the right to alter functions or specifications without prior notice.
SPEAKER PROTECTION
Each channel is fuse protected on the positive and negative power supply rails. Electronic short-circuit protection with a progressive
characteristic. The output power is progressively reduced at impedances below 1.7 ohms. The power amplifier can be run into short-
circuits for a long time without damage, and is open circuit and mismatch proof.
DISTORTION
THD 20 Hz-20 kHz and 1 W-600 W 4 ohms 0.08 %
THD at 1kHz and 600W 4 ohms 0.03 %
DIM 30 at 300 W 4 ohms 0.02 %
CCIF (13 and 14 kHz) at 200 W 4 ohms 0.02 %
SMPTE (60 Hz and 7 kHz) at 300 W 4 ohms 0.05 %
POWER BANDWIDTH 10 Hz-50 kHz
Slew rate 40 V/µs
OUTPUT IMPEDANCE 1 kHz 0.07 ohm
HUM AND NOISE below max power <- 105 dBA
CHANNEL SEPARATION 1 kHz 90 dB
10 kHz 75 dB
PHASE AND DELAY
Deviation from perfect delay 150 Hz-20 kHz ± 2°
Total delay input to output at 4 ohms 4.1 µs
INPUTS
Sensitivity, switchable for full output into 4 ohms 0.775 or 1.7 Vrms
Gain, switchable 36 dB or 29 dB
Impedance 20 kohms, balanced
Common mode rejection at 1 kHz 50 dB
FRONT PANEL
Gain controls (2) Channel A - B
Output display (2) red + (10) green LED´s Fast peak - slow release
Temp indicator (2) yellow LED´s 80° C at heatzink
VHF indicator (2) yellow LED´s > 20 kHz at full power
On indicator (2) green LED´s DC rail voltage for channel A and B
REAR PANEL
Input connectors (2) XLR type 3 pin female (pin 2+), and (2) 1/4” jack
Output connectors (2) Neutric 4-pole speakon connectors (pin 1+ output)
Switches:
Gain 36 dB or 29 dB
Link Tandem mono, channel A and B
Polarity B Reverse polarity of channel B
Clip limiter A and B On - Off
POWER
Operation voltage 120 V - 260 V AC
Full output power 230 V AC
Peak inrush current 83A
OVERALL DIMENSIONS
mm (inch) 483 (19”) W
x 88 (3.5”) H
x 355 (14”) D
WEIGHT 18 kg (40 lbs)
APPROVALS CE Emission EN 55 103-1, E3
Immunity EN 55 103-2, E3, with S/N below 1%
THX version: at normal operation level 4)
Safety EN 60 065, class I
LAB 1000t
MAX OUTPUT POWER
1)
8 Ωstereo
4 Ωstereo
2 Ωstereo 3)
8 Ωbridged
4 Ωbridged 3)
EIA
1 kHz
at Clip (1% THD)
380 W
600 W
700 W
1300 W
1400 W
FTC
20 Hz-20 kHz
at 0.1% THD
350 W
550 W
600 W
1200 W
1300 W
IHF
Peak Power
20 ms burst
450 W
750 W
900 W
1500 W
1800 W
Calculated 2)
Peak Power
500 W
900 W
1300 W
1800 W
2600 W
3) Though the LAB 1000 can drive a 2 ohms load, we recommend you to
keep the load impedance on 4 ohms or above in professional applica-
tions, which demand large amounts of continuous power.
4) Normal operation level 1/8 of full power or -9dB below clip point.
1) Specifications measured with 230 V regulated AC
2) Calculated by using peak voltage and nominal
speaker impedance