Ab international 821 a brochure

Page 1

ADVANCED
TECHNOLOGY
DESIGN SEFi/ES

43.2% can
AMPLIFIER SYSTEM

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ADVANCED TECHNOLOGY SPECIFICATIONS
Advanced Technology Design Series N from AB TYPE: ng International is a modular system of high performance °n oar 59 p' 9
power amplifiers and electronic signal processing that Power output: mat Model: 500 w at 8 {2
may be precisely tailored to the specific requirements of $033230
professional loudspeaker components.
821 ONLY BridgeMode221000wat1BQ

The 821 A consists of power amplification. signal :% 'vv 2:2 2 (2000 w peak)
processing and precise control for high-performance ~ .
subwoofer and lull-range loudspeaker systems. Placing Vflllage Galni 32.5 dB. dual made: 35-5 dB. bndge mode

all signal processing and controls within a single chassis
sewed by a common power supply reduces cost and
avoids the interface and operational problems usually
encountered with separate components. Included in the
821A are two summing inputs. two power amplifiers.
selectable high pass and low pass filters, low frequency
Thiele~Smali alignment equalization and a precision step
output attenuator.

The power amplifier stages in the 821 A are fully
complementary and operate from a six-level logic-gated
power supply that adapts to the waveform of the input
signal. providing only the DC rail voltages necessary for
undistorted amplification. The result is tremendous
output capability. cool operation and unconditional
stability over an exceptionally wide range of load
conditions. The output amplifiers may be operated in the
dual or bridged mono modes. with up to 2000 watts peak
output power available. A delayed-ON. instantOFF
muting control cirwit allows internal supply voltages to
stabilize before loudspeakers are connected.
Connections to the loudspeakers are instantly removed.
should the AC power be interrupted.

For users desiring specific nonstandard features and/or
signal processing. a wide range of options are available
lor this purpose. See 'Optional Equipment brochure for
details.

lnput sensitivity: 1.5 Vrms (referred to rated an output)

lnput impedance: 15 kt), balanced or unbalanced

Noise iovel: too dB below rated outputs. unweighted

Signal processln :3 S stem high pass (20 orao Hz) 2nd-order

9 derived w/adjustable underdamping for

assisted Thiele-Small alignments. system
low pass (50 or 80 Hz) Alhorder Bessel
response

Controls: Power. 5 stem level. high pass frequency

select. V equalization, low pass
lrequency select. output mode (dual or
bridge mono)

(2) XLR-3 (bal.) with ground lilt switch, (2)

input connectors:
. tl4-inch (unbal.)

Power requirements: 120/240 VAC. 50/80 Hz. 500w (avg)
1800 w (max)
Physical: 5-1I4'(13.3cm)H x 19' (48.3w) w x

13-1/2 (34.3w) D: 46 lbs. (20.9 kg.)

Leontinuous erou tetlessthano.1%1iiD.20Hzto 20kHz.one
channel driven!w l9

2. Maxi continuous output power with both channels driven or in pridge
mode ism by line card capacity and power supply storage capability.

3 Awide e of rionel crossovers Ind 5' process is available.
Please refer a: 'opnognal equipment tor detaiigfll m

Page 2

f FEA TUBES AND CONTROLS

f

The 821A consists of two
high-power amplifiers in
the dual-mono mode driven
by a signal-processing
control module. The control
module incorporates user-
selectable high pass, low
pass litters, monitoring and
equalization.

Two isolated and summed
balanced inputs enable
bridging the LR line-level
signals in two-channel
systems tor subwooler

applications. In standard
configurations, the high
pass filters are 2nd-order
(12 dB/octave) M-derived,
with selectable corner
frequencies of 20 or 30 Hz.
Adiustable underedamping
allows 2, 4 or 8 dB boost
just above the high pass for
electrically assisted
loudspeaker alignments
The low-pass litters are 41h
order (24 dB/oct.) Bessel
linear phase, selectable
between 50 and 80 Hz.

At right are the amplitude
response contours of the
system with 30 Hz high

pass and 80 Hz low pass
selected Shown are tlat, 35
2, 4 and 6 dB boost

associated with the high

pass lilter. The equalizer-

litter control is below.

to

HPQ

2 3
hequency (H1)

A 56739

00

4.

input A

(Unbal)

Input B

f
SIGNAL FLOW 421

Level

spa,
BRlDGE

500W

k

High Pass/E0

W

Low Pass

Cli

Sig.

o 0 MM 0 i: ll
0 0 Above and right are sample
mnlrol settings and the 2 3 A. 5 s 7 a 9
resulting response. 30 Hz 0 lrcqmncv m1) "3
«so u high pass with 4 dB boost
st I???" :1 44 and 50 Hz low pass are shown.
QQQDQQG 9999 [1999 l , . LEVEL
TIl If At rl ht IS the preciSion output
' leve control used in the 821A. 51 2 4 816m «B
The individual switch positions ' 3 , - f 6 7
are calibrated for dB insertion Eggfiagg
O 0 loss, and selected values sum
directly. 125 dB attenuation is
illustrated
O 0003 mamzncomnot O
k J
r l
SIGNAL FLOW 821 Output A
+
500W .
Indicators
.1 Clip
2 \ Z _ BTL
/ -~Slg.
Level Low Pass High Pass/E0

Output-B

Output A
+

Indicators

BTL

é.-

Output-B