Altec Lansing 9444B User Manual

nd off

9444B and 9444B/SA

Anniversary Series Power Amplifier

Operating and Service Instructions

ALTEC LANSING® CORPORATION

u MARK rV company

P. O. Box 26105 • Oklahoma City. OK e 73126-0105 USA ® Tel: [phone] • FAX: [phone]

Operating and Service Instructions for the Altec Lansing 9444B Power Amplifier

Table of Contents

1 ELECTRICAL.................................................................................................................................................

1.1 120 V ac, 50/60 Hz Power Connections......................................................................................................

1.2 220/240 V ac, 50/60 Hz Power Connections...............................................................................................

2 INSTALLATION............................................................................................................................................

2.1 Rack Mounting ...........................................................................................................................................

2.2 Ventilation ...................................................................................................................................................

3 SIGNAL CONNECTIONS................................................................................................................................. -

3.1 Input Connections ...........................................................................................................................................-

3.2 Line Outpxrt Connections...........................................................................................................................

3.3 Output Connections........................................................................................................................................ 2

3.4 Output Cable Selection................................................................................................................................... -

3.4.1 Calculating Power Losses with 8 ohm Loads......................................................................................

3.4.2 Calculating Power Losses with 4 ohm Loads

3.0 Damping Factor...........................................................................................................................................

3.5.1 Calculating the Maximum Length of Cable for a Specified Damping Factor

3.6 Speaker Protection Fuse Selection..............................................................................................................

3.7 Compression Driver Protection Capacitors ................................................................................................

......................................................................................

.....................................

3

• i

4 OCTAL ACCESSORY SOCKETS..................................................................................................................... 5

5 PROTECTION SYSTEMS ............................................................................................................................

5.1 Load Protection Circuitry............................................................................................................................

5.2 Amplifier Protection Circuitry ....................................................................................................................

5.3 Protect Indicator...........................................................................................................................................

6 OPERATION..................................................................................................................................................

6.1 Dual Mode of Operation....................................................................................................................................

6.2 Bridge Mode of Operation .............................................................................................................................. P

7 IN CASE OF PROBLEMS .............................................................................................................................

8 SPECIFICATION................................................................................................................................................ S

9 SERVICE INFORMATION........................................................................................................................... L2

9.1 Trimpot Adjustments.......................................................................................................................................2

9.2 Equipment Needed........................................................................................................................................ ;2

9.3 Adjusting R39, the LF Cancel Trimpot.......................................................................................................

9.4 Adjusting R26, the BIAS Trimpot................................................................................................................... ù

9.5 Adjusting R23 and R24, the Negative and Positive Current Limit Trimpots.............................................. 3

9.6 Checking the Short Circuit Current ............................................................................................................ . ^

9.7 Ordering Replacement Parts .......................................................................................................................

9.8 Factory Service

9.9 Technical Assistance ..................................................................................................................................

...

.......................................................................................................................................

.

10 THE 9444B/SA ..............................................................................................................................................

ALTEC LANSING^ CORPORATION • a Mark TV Company

Operating and Service Instructions for the Altec Lancing 9444B Power Amplifier

1 ELECTRICAL

Two amplifier models are
available. One model has a 50/60
Hz power transformer with two

120 V ac primary windings. These
windings may be wired in parallel
or series for operation at either

120 V ac or 220/240 V ac. The ot
her amplifier model is for export
into countries where the ac line
voltage is 100 volts, 50/60 Hz. The

next two sections refer to the first

model with the dual 120 V ac pri

mary windings.

1.1 120 V ac, 50/60 Hz
Power Connections
The amplifier is provided

with the primary of the power tra

nsformer strapped for 120 V ac
operation from the factory. Refer
to Figure 2a for the wiring details.

WARNING: Verify that the power

transformer’s primary circuit
configuration is correct for the
intended ac line voltage BEFORE
applying power to the amplifier.

1.2 220/240 V ac, 50/60 Hz
Power Connections
The power transformer

has two 120 volt primary windings

which can be connected in paraDel
for 120 V ac line voltages, or in
series to meet 220/240 V ac requi

rements. Use the following pro
cedures to re-strap the primary of
the power transformer for 220/240
V ac applications.

1. Make sure the amplifier is
not connected to any po
wer source.

2. Remove and save the ele
ven screws securing the
top cover. There are three
screws on each side and
three along the top-rear
edge of the chassis. In
addition, you must remove
the two iimermost screws
inset into the top bumper
strip. Refer to Figure 1 for
the exact screw locations.

Figure 1 Top Cover Removal

3. Locate terminal blocks
TBl and TB2 on the side
of the chassis near the
rear input PC board. Re
connect the leads as
shown in Figure 2b.

4. Install the top cover with
the eleven screws previ

ously removed. Two scr
ews г!ге longer than the
others removed from the
sides and rear. These

longer screws install into
the reeirmost position on

each side of the chassis.

5. Install an 5A fuse, Littel-

fuse Type ЗАВ 5A/250V
slo-blo 326-series ceramic
body or equiv.

2 INSTALLATION

2.1 Rack Mounting

The amplifier ’nay be in
stalled in a standard 19 inch
equipment rack. It :■ .niires 5V4
inches of vertical rack fipace and
secures to the rack -iibinet with
the four rack mount screws emd
cup washers provided ui the hard
ware kit.

2.2 Ventilation

The amplifier must be ad
equately ventilateo ' e, avoid ex
cessive temperatur- r- ^. It should
not be used in area.' where the
ambient temperature '.xceeds 60
°C (140 °F). To determine the am
bient air tempera: i. : r, operate the
system in the rack until the temp
erature stabilizes. Measure the
ambient air with a bull.-type ther
mometer held at tlie Dottom of the
uppermost amplifier Do not let
the thermometer torich the metal

chassis because the chassis will be
hotter than the ambjent air. If the

ALTEC LANSING* CORPORATION • a Mark IV Company

Operating and Service Instructions for the Altec Lansing 9444B Power Amplifier

typical output connections.

3.4 Output Cable Select I<
Speaker wire size pla>^: ft'.

important part in quality so.,
systems. Small wire gauges c.
waste power and reduce the dam
ping factor at the sp>eaker ter t-

Lnals. Ibis can add coloration a;
muddiness to the sound. To Ы-'г.
offset this problem. Table I r
been assembled to enable yoi;
calculate the power losses in e
speaker cable.

3.4.1 Calculating Powe

Losses with 8 ob^
Loads

To calculate the to
power loss in the speaker cable,
multiply the power loss per Го
(or meter) of the 2-wire cal

selected from Teible I Ьз' и»

length of the cable in feet
meters). For example, suppos. a.
installer uses 160 feet of 10 GA
wire cable with an 8 fl speai •
^stem. Ibe total power loss

Figure 2 Primary Wiring Configuration for 120 V ac and 220/240 V ac

air temperature exceeds 60 °C
(140 ®F), the equipment should be
spaced at least 1.75 inches apart
or a blower installed to provide
sufficient air movement within
the cabinet.

WARNING: Do not operate the

amplifier within a completely

closed unventilated housing.

S SIGNAL CONNECT

IONS

3.1 Input Connections
Balanced input connect

ions may be made to either the
barrier strip or the female XLR
connectors. For single-ended in
puts, strap the low (—) input to
ground (pin 3 on XLR). Other
wise, the electronically-balanced
input stage will see 6 dB less in
put signal level than with a bzJ­anced input. Refer to Figure 3 for

typical input connections.

3.2 Line Output Connect
ions
The XLR and barrier strip

connectors are wired in parallel.
Pin 2 of the XLR is the (-f-) input

on the barrier strip, and pin 3 is

the (—) input. Since the input im
pedance of the electronically­balanced input stage is high (15
kohms), there is minimal loading
on the signed source. When the
input connections are made to one
connector, the other may be used
as an auxiliary line output to feed
other high input impedance equip
ment. Refer to Figure 3 for poss
ible applications.

3.3 Output Connections
Output connections are

made to the four terminal barrier
strip connector located on the rear
of the unit. Refer to Figure 4 for

the cable is;

Total Power Loss in cable

= 0.0509 watts/foot X 160 feet

= 8.1 watts

Does this mean that whenever
amplifier produces 200 wattr
output power, 191.9 watts (20^
watts minus 8.1 watts) will Ы
delivered to the 8 ohm load? NOI

Tire actual load impedance is
ohms plus the resistance of t
cable (0.00204 ohms/foot thu'

160 feet) for a total load imp
dance of 8.3264 ohms. At the 8 ,
rated output power, the outpu
voltage is 40 V rms. Therefor
the amplifier produces 192.2 watv; .
with this load instead of 2i''.
watts. This was calculated
.squaring the voltage and dividinr
by the load impedance (40^ divl
ed by 8.3264 ohms). As a resui: ,
the actual power delivered to
load is
minus 8.1 watts).

184.1 watts (192.2 watr

ALTEC LANSING* CORPORATION • a Mark IV Company

Operating and Service Instructions for the Altec Lansing 9444B Power Amplifier

Losses with ohm
Loads

SOURCE

Figure 3 Typical Input Connections

AMPLIFIER’S OUTPUTS

AMPLIFIER’S INPUTS

LOUDSPEAKER LOADS

AUX OUTPUTS

when using a 4 ohm г.р‘ =акег sys

tem, multiply the loss 3 ohms

by 8. In the above example, the 10
GA wire would comiuaie 24.3
watts of power while !■ 18 GA
wire would waste 15-‘ watts -

more than half of the amplifier's 4

ohm power rating.

3.5 Damping Fact-.; r
factor rating of air amplifier, the

greater the ability of Üi- amplifier
to control unwanted sp- sker cone
movements. When a signal drives
a woofer, current flow;¡ ’.hrough
the voice coil creates ■ uagnetic
field. This field inters. ^ with the
permanent magnetic field in the
gap and forces the combination
cone and voice coil aiisembly to
move outward. When i he signal is
removed, the assembly moves in
ward but its momeid.ii causes it
to overshoot its resting point. This
overshoot will damfx n iLself out
eventually but the unwanted mo
vements can add consirierabie dis
tortion products to 111-' .'iound

To calculate ti: losses

The higher thi diunping

Figure 4 Typical Output Connections

Had 18 GA wire been used in the
above excunple, the loss in the
cable would have been 51.9 watts.
This example illustrates the im

portance of using the proper wire
size.

3.4.2 Calculating Power

In the process of movitig inward
through the magnetic field, the
voice coil assembly generates a
current of opposite polarity to the
original signal. This current

induces a voltage or “1- ick EMF”
which travels through ihe speaker
wore to the ampiiiler's output.
The lower the amplifier’s output
impedance, the faster the over
shoot of the voice coil vill dampen
out. The output impeilance of an
amplifier can be calculated by

dividing the rated output impe

dance, typically 8 ohms, by the
damping factor. The U-144B has a
damping factor rating of 200
which correspond^ .■ an output
imp>edance of 0.04 ohms.

S.tS.l Calculating the

Maximun i<‘ngth of
Cable for ü Specified

ALTEC LANSING^ CORPORATION • a Mark IV Company

Operating and Service Instructions for the Altec Lansing 9444B Power Amplifier

Damping Factor Spec
ification at the Load

The damping factor rating
is ^rpically never realized at the
load because of the resistance of
the cable (and other factors such
as the contact resistance of an
output relay or the resistance of
an output fuse). The damping fac
tor at the load should be 30 for
general paging ^sterns and 50 for
high fidelity music ^sterns. Econ
omics usually dictate, however,
that these numbers are cut-in
half. The resulting damping factor
at the load should be based on
experience and customer satis
faction. Once a minimum damping
factor is determined for a partic
ular type of installation, the fo
llowing equation can calculate the
maximum length of 2-wire cable
which can be used to achieve the
minimum damping factor specified
at the load;

Max. Length of 2-wire cable in
feet

ZL — Zo

= DF

DCR/ft

where

ZL is the load impedance

to connect to the amp

lifier;
Zo is the amplifier’s
output impedance (0.04
ohms for the 9444B);
DF is the minimum

permissible damping

factor at the load; and

DCR/ft is the DC resis

tance of the 2-wire cable
per foot from Table I.

The same equation can be used to
calculate the maximum cable leng
th in meters by substituting the
DCR per meter value from Table
I.

Let’s use the equation. Suppose
ZL equEils 8 ohms, Zo = 0.04
ohms, and the minimum damping

Table I 9444B Power Losses in 2-wire Speaker Cable

AWQ
(GA)

6
8

10 0.00204
12 0.00.124
14 0.00510 0.1286
16

18 0.01302
20
22 0.03292 0.8163

DCR/ft

(n/ft)

0.00081

0.00121

0.00819

0.02070 0.5148

factor at the load is 25. In add
ition, 18 GA cable is preferred.
Then, the maximum length of 18
GA cable which can be used to
achieve a damping factor of 25 at
the load is:

Power Cable Croaa- Power
Loss/ft
(walWft)

0.0201

0.0302

0.0509

0.0809

0.2043 1.31

0.3244 0.82

SccI ional
area (mm*)

13..30 0.00264 0.0661

8.36 0.00421 0.1051

5.26

3.31

2.08 0.01691 0.4210

0..52 0.06764 1.6627

0.33

DCR/nietcr

(n/m)

0.006CO

0.01003 0.2650

0.02685 0.6667

0.04289

0.10658 2.5950

V is the stepped-up ii.
age of the system;
Pout is the rated output
power of the amplifier:
Zo is the output impetl
ance of the amplifier (O.G­ohms for the 9444B);

8 — (0.04)

^5

___________________

0.01302 n/ft

= 21.5 feet

ZL is the load impedaiic.;
DCR/ft is the DC resis
tance of the 2-wire cabL
per foot from Table I; anti
DF is the minimum pf

Sometimes it may be necessary to

locate the speaker 100 feet or

missible damping facte r
the load.

more away from the amplifier. In
this situation, a much larger
gauge cable is required. However,
this may not be practiced or eco
nomical. 'The size of the 2-wire
cable can be greatly reduced by
stepping up the output voltage of
the amplifier to 70, 100, 140, or
210 volt, using an output trans
former, then stepping down the
voltage at the load. Such a system

Suppose a 210 volt ^stem werv
used at a 600 watt power level '
drive an 8 ohm load with a min:
mum damping factor of 25. Using
the same 18 GA cable as before,
the maximum length can now t)6
198 feet. Power companies
this teclinique to transfer large
amounts of power over great dis
tances.

is shown in Figure 5.

3.6 Speaker Protection.
The maximum length of 2-wire ca
ble in this situation can be ap
proximated from the following
equation:

irable to use in-line fuses (fuses i:.
series with the output) to protect

Fuse Selection
Sometimes it may be des

loudspeciker ^sterns (or the amp
Max. Length of 2-wire cable in
feet

lifier). It is difficult, however,

determine the proper fuse valttv

with the correct time lag anrl

1 Zo

(Pout)(DCR/ft) DF ZL

overload characteristics to match

the limitations of a speaker sy-s-

tem. The values shown in Table II
where

should serve only as a guide. To

Loss/raotc
(watts/m

0.1669

1.0609

ALTEC LANSING* CORPORATION • a Mark IV Company

Operating and Service Instructions for the Altec Lansing 9444B Power Amplifier

Lansing recommends using a ca^
acitor between the aimplifier and
the compression driver to supp
ress low frequencies an; ossible
DC. Refer to the exam : e in Fig
ure 4.

In choosing a value, one must be
careful not to interfere -vith the
crossover frequency. A-: -general

rule, select a сарае:' whose
break frequency, with respect to the
load, is 3 dB down, at approximate
ly Vi of the high pass comer fre
quency.

Mylar capacitors witli at least a

100 volt ac rating are rec-.nmend-

ed. Table III shows ‘ e recom

mended capacitor vnhies for use
with 8 and 16 ohm dri > crs at pop
ular crossover frequencies.

Figure 5 High-voltage Distribution System

use, determine the power rating

where
and load value. Then, select a
standard value fuse of the next
smaller value to the one listed in
the table.

Use 32 volt fuses if possible; they
Table П Calculated Output Fuse

Values

typically have the lowest internal

resistance which will help mini

mize deterioration of the damping

Power 4 n

(wutta)

100
150
200
300
400
600 9.07

Load

3-70 2.62 1.85

4..54 3.21

5.24 3.70 2.62

6.42

7.41 5.24

8П
Load

4.54

6.42 4.54

16 n
Lead

2.27

3.21

3.70

factor at the load. Refer to the

example in Figure 4.

3.7 Compression Driver

for mid to high frequency sound

reproduction, are much more sus

ceptible to damage from low fre
The values are calculated for fast-

blow fuses which carry 135% of

their current rating for an hour

but will blow within 1 second at

200%. Other fuse values may be
calculated for different power

levels from the following equation:

quencies than large cone loud

speakers. Even though an elect

ronic crossover may be employed,

problems may arise in the cables

between the crossover and the

power amplifier, or from raisad-

justment of the crossover. Either

of these situations could apply low
Fuse value =

(Pout X ZL)^ amps

ZL X 1.35

frequency signals or hum to the

driver and cau.se damage. To pre

vent a potential mishap, Altec

Pout is the output power
rating of the amplifier;
and
ZL is the load impedance.

Protection Capacitors
Compression drivers, used

Table Ш Compre; lí-- ; t fLl

Driver

Protection Capacitors

Crossover 8П 16
Frequency Driver Driver

500 Hz 80 ¿I- 40 (iF

800 Hz 50 nl­1000 Hz 40 цГ
1250 Hz 33 Цр îGnF
2000 Hz 20 jiF 10 liF

3150 Hz
6300 Hz 6 jiF 3 (iF

12 цГ

n

25 irF

20 p.F

6 piF

4 OCTAL ACCESSORY

SOCKETS

Two octal sockets permit a
variety of plug-in acc.er -jori^ to be
used with the amplifier Normally,
one “U” jumper is inserted bet
ween octal socket 8 and 1,
and another betwei:: i ins 7 and 6.

These jumpers must remain in

place for the amplii-rr to operate

when not using ar.‘: accessory
modules. To use with in accessory

module, remove iau save) the

jumpers and insbi]] .he module

making sure the kev >n its center
post aligns with til* ;Toov6 in the
female socket. For operation, refer
to the instructions rovided with

ALTEC LANSING* CORPORATION « a Mark IV Company

Operating and Service Instructions for the Altec Lansing 9444B Power Amplifier

the module. Schematically, the
module will be inserted between
the input connector and the bal
anced input stage.

Electronic modules are powered
from a bipolar 15 volt supply in
the amplifier, "nie supply is cap
able of supplying up to 25 ma DC
of current. Currents in excess of
25 ma DC may prevent the ampli
fier from disengaging from its
built-in protection meclianisms.

PROTECTION

TEMS

5.1

ently protects its load from
startup/shutdown transients, DC,
and large subsonic signals.

circuit was designed specifically
for the amplifier. It features a
variable current limit which is a
function of the output signal volt
age. As a result, tlie amplifier can
deliver the rated currents into
rated loads but substantially lim
its the current into low impedance
or shorted loads (shorted output

terminals). Once the short is re
moved, however, the amplifier will
resume normal operation.

A dual speed fan is also incorp
orated to provide efficient cooling
under the most demanding condi
tions. When the heatsink temper
ature at the fin tips reaches ap
proximately 88 “C (190 ®F), the
fan automatically switches to high
speed operation. As the temper
ature cools to approximately 78 “C
(172 °F), low speed operation is
once again resumed.

The heatsink is also thermally
equalised to prevent the output
devices nearest the fan fi-om op
erating at a cooler temperature

Load Protection Cir
cuitry

Each channel independ

5.2 Amplifier Protection Circuitry A unique current-limiting

SYS-

than the devices at the opposite
end. This minimizes the thermal
gradient across the heatsink and
forces the devices to operate at
more nearly the same tempera
ture. Tliis equalizes the lifetimes

and reliability characteristics of

the output devices so that no one
device becomes the weak link in
the chain.

Should the heatsink temperature
of a channel remain excessively
high, the affected channel will
shut down automatically. W^en
the output devices cool to a safe
operating temperature, the chan

nel will automatically resume

normal operation.

5.3 Protect Indicator Tlie “PROTECT” LED

does not turn-on abruptly as
others may do; its intensity is
allowed to vary. As a result, its
degree of brightness serves as a

relative indicator of tire severity of

the current oprerating conditions
e.g., the brighter the LED, the
greater the stress on the chan-

nel(s). This provides a visual not

ification well in advance of any

impending shutdown.
Although the channel may stiU

opwrate with the LED apparently
at full brightness, a total shut
down will occur within a few sec
onds unless the operating condit

ions improve. If a shutdown does
occur, the channel will resume

normal ojjeration as soon as its
devices have cooled to an accept
able temperature.

6

6.1

ation, the channels may be oper
ated independently. After install
ation and hookup, verify that the
mode switch, located on the rear

penel, is in the “DUAL” position

and rotate the level controls fully

OPERATION
Dual Mode of Op>er-

ation
In the dual mode of oper

counterclockwise (full attenr
ion). Input a 0 dBu (0.775 V ;
nominal signal level and ^
pewer. Slowly increase the
controls until the desired ou­pewer is obtained. If ei'
“CLIP” LED illuminates, re-J
the output with the cheumel
control or reduce the input si;,
level at its source.

WARNING: Never attempt to c-

nect the outputs of the two cka
nets in parallel.

6.2 Bridge Mode of Op­ation
After installation

hookup, verify that the m<
switch, located on the rear 1x1:1?
is in the “BRIDGE” px>sition. R
ate both levels controls ft. ._
counterclockwise (full attenuu.
ion). Input a 0 dBu (0.775 V n­nominal signal level into chanu

1 only and apply pjower. Slowly
crease the level control of chanr
1 until the desired output piowoi

is obtained. If either “CLIP” LL
illuminates, reduce the output le
el with the level control or redu
the input signal level at its sou:

CAUTION: Be sure that no inpi

connections are made to channel
and that its level control is fw
counterclockwise (OFF).

WARNING: The bridged outp:
mode provides a true balanced-it

ground output. Do not use any fc-

equipment to test or evaluate thi
amplifier which does not ha‘

floating grounds.

In Case of Problems
Please check the followii.

items:

Verify that the ampliCe:
is properly connected :
an ac pxjwer source an>
that the source is active.

Verify that the input con
nections are proper!

ALTEC LANSING* CORPORATION • a Mark IV Company

Operating and Service Instructions for the Altec Lansing 9444B Power Amplifier

made. Refer to Figure 3.

3. Verify that the output
connections are prof>erly
made. Refer to Figure 4.

4. Check the input and out
put cables for proper
wiring and continuity.

5. Check the signal source
and the load.

Insure that the two jump
ers for each octel socket
are properly installed (if
not using optional plug-in
modules).

Insure that any accessory
modules installed do not
draw more than 25 ma
DC of current.

8.

NOTICE: Repairs performed by
other than authorized warranty

stations (Dealers) or qualified
persomiel shall void the warranty
period of this unit. To avoid loss

of warranty, see your nearest Altec

Lansing authorized dealer, or call

Altec Lansing Customer Service

directly at [phone], FAX

[phone], or write:

Altec Lansing Customer

Service/Repair

10500 W. Reno
Oklahoma City, OK 73128
U.SA.

Check that the mode
switch is in the desired
position.

AJLTEC LANSING^ CORPORATION • a Mark IV Company

Operating and Service Instructions for tfie Altec Lansing 9444B Power Amplifier

8 SPECIFICATIONS

Conditions:

1. 0 dBu = 0.775 volts rms.

2. Dual mode ratings are for each channel.

3. Both channels operating at rated output power
unless noted.

4. 120 volt ac line input voltage maintained for all
tests unless noted.

Continuous Rated Output Power:

(20 Hz - 20 kHz at less than 0.1% THD)
Dual mode, 4 D: 300 watts/ch

Bridge mode, 8 SI: 600 watts
Dual mode, 8 SI: 200 watts/ch
Bridge mode, 16 D; 400 watts

Continuous Rated Output Power to Subwoofer:

(20 Hz - 1 kHz at less than 0.1% THD)

Dual mode, 4 O: 375 watts/ch

Bridge mode, 8 D: 750 watts

Dual mode, 8 Si: 225 watts/ch

Bridge mode, 16 fi: 450 watts

Maximum Midband Output Power:

(Ref. 1 kHz, 1% THD, @120 volts ac line voltage)

Dual mode, 4 SI: >400 watts/ch

Bridge mode, 8 SI: >800 watts

Dual mode, 8 SI: >250 watts/ch

Bridge mode, 16 SI: >500 watts

(Ref. 1 kHz, 1% THD, @108 volts ac (10% sag))

Dual mode, 4 SI: >325 watts/ch

Bridge mode, 8 il: >650 watts

Dual mode, 8 il: >200 watts/ch

Bridge mode, 16 fi: >400 watts

(Ref. 1 kHz, 1% THD, @100 volts ac (17% sag))

Dual mode, 4 il: >230 watts/ch

Bridge mode, 8 il: >460 watts

Dued mode, 8 il: > 175 watts/ch

Bridge mode, 16 il: >350 watts

Headroom (Before clip): S1 dB

(Ref. 1 kHz, 1% THD, any mode)

Frequency Response: 10 Hz - 90 kHz

(Ref. 1 kHz, 1 watt output, +0/—3 dB)

Power Bandwidth: 20 Hz - 20 kHz

(Ref. 1 kHz, +0/—1 dBr where 0 dBr = rated output

power in any mode)

Voltage Gain:

(Ref. 1 kHz)

Dued mode, 4 il or 8 il;

33 dB

Bridge mode, 8 or 16 Q: 39 dB

Input Sensitivity for Rated Output Power:

(Ref. 1 kHz, ±0.15 dB)
Dual mode, 4 il:
Bridge mode, 8 il:
Dual mode, 8 il:
Bridge mode, 16 SI:

Maximum Input Level:

(Ref. 1 kHz)

Input Impedance;

(Ref. 1 kHz)
Balanced:
Unbalanced:

Polarity:

Phase Response:

(Any mode)
20 Hz:
20 kHz:

THD:

(Any mode, 30 kHz measurement bandwidth)

IMD (SMPTE 4:1); <0.05% (Typ. <0.01%)

(Any mode)

TIM (DIM 100): <0.05%

(Any mode)

Rise Time: <6 psec

(Any mode, 10% to 90%)

Slew Rate:

Dual mode, 4 or 8 il: >30 V/psec
Bridge mode, 8 or 16 il; >60 V/psec

Damping Factor;

(Dual mode, 8 D)
20 Hz - 1 kHz:
20 kHz:

Crosstalk: <75 dBr

(Ref. 1 kHz, 0 dBr = rated output power into 8
ohms, single channel operating)

Noise; > 100 dB

(Below rated output power, A-weighting filter, 8 f ‘

+0.1 dBu (0.78 V rms
+0.1 dBu (0.78 V nus'
+ 1.2 dBu (0.89 V rm;
+1.2 dBu (0.89 V rm

+20 dBu (7.75 V rm.s

15 kil
15 kD

Positive-going sign­applied to pin 2 of X' :

or (+) of barrier strip

produces positive-gv ;
signal at (+) outp
terminal.

<+25°

>—15°

<0.1% (lyp. <0.01%.

>200

>75

ALTEC LANSING^ CORPORATION • o Mark IV Company

Operating and Service Instructions for the Altec Lansing 9444B Power Amplifier

dual mode, 50/60 Hz ac line frequency)

Amplifier Protection:

Load Protection;

Cooling:

Heatsink:

Fan:

Output Topology:

Output Type:

Dual mode:
Bridge mode:

Output Devices:

Total number:

Pdmax rating:
Vceo:
Ic:
Tjmax:

Controls and Switches:

Rear:
Front:

Front Panel Indicators: Power LED, Clip LED (x

Connections;

Input:

Shorted output term
inals, Over-temperature,
RF interference

Startup/shutdown trans
ients, DC faults. Sub
sonic signals

Thermally equalized 3/16
in aluminum black ano
dized heatsink

Thermostatically con
trolled dual speed fan.
Approximately 50 CFM
at low speed and 100
CFM at high speed. Ball
bearing fan has mini
mum life rating of
50,000 hours at 25 °C
ambient temperature

True complementary
symmetry with grounded
collectors (no mica
insulators means better
heat transfer)

Unbalanced, each chan
nel
Balanced

16 devices
250 watts
250 volts DC

16 amps DC
200 °C

Mode switch, Two input

level controls
Power switch

2),Protect LED (x 2)

6 terminal barrier strip,
Female XLR (x 2),
Octal accessory socket (x

2), powered with ±15

volts DC at 25 :'-¡i.

Output:
Power:

Fuse ТУре;

Power Requirements;

Operating ac Voltage

Range:

Power Consumption/

Heat Produced:
(Both channels operating in dual mode '.viih 1 kHz
sinewave input signal at stated output power into 4
Cl loads)

idle:
l/8th max

midband power:
l/3rd max

midband power:

Rated output power:
Max midband power:

Operating Temperature

Range:

Dimensions (Rear of rack ears to max depth):

Barrier strip

6 ft (1.83 m). :^-wire, 16
GA power cord with

NEMA 5-15 ;:!:jg/rEC
Littelfuse TVps ЗАВ 10

A/250 V Sl^Blo® 326-

series ceramU ..irtridge

body, or equivakmt (for

120 V ac use
120 V ac, 50/6Й Hz, 1000

watts (configurable to

220/240 Vac. ; 00 Vac,

5 0/60 Hr model

availeihle.

Operates line
voltages as ! iv as 90
volts (at redv:oitl output
power) assu;-:!T!r: a 120 V
ac nominal i; '

72 watt&'0,24ò кВТи/h

720 watta'2.100 ,kBTU/h

1,068 w.4t.i.s/2.702
kBTU/h

1,464 w«*t,s/2.938
kBTU/h
1,680 w-as/2.873

kBTU/h

Up to 60 C (140 “F)
ambient

5.25 in Hx 19 inWxl3
in D
(13.3 cm b -^8.3 cm W
X 33 cm DI

ALTEC LANSING* CORPORATION • a Mark IV Company

Operating and Service Instrifctions for the Altec Lansing 9444B Power Amplifier

Shipping Weight:
Net Weight:
Colon
Enclosure:

Standai*d Accessories:

Optional Accessories:

42 lbs C19.1 kg)
34 lbs (13.5 kg)
Black
Rack mount chassis, 16

GA steel, 3/18 in 5052
aluminum alloy front
panel

4 - “U” jumper plugs for
octal sockets (2 per
socket, installed)

1 - Operating Instruct
ions and Service Manned
1-5 A/250 V fuse (for
220/240 V ac use)

14712A Power Limiter
15515A Input Bridging
Transformer with Pad

15524A 300 watt 70 volt

Transformer

15525A 600 vpatt 70 volt

Transformer

15367A 300 watt Auto
former

15581A 24 dB/oct

Link wit2-Riley C rossover

15594A-XXX 18 dB/oct

Low Pass Filters
15595A-^ 18 dB/oct
High Pass Filters

The “-xxx” represents various corner frequencies
available for the corresponding filter.

ALTEC LANSING CORPORATION continually
strives to improve products and performance.
Therefore, the specifications are subject to change
without notice.

Slo-Blo® is a registered trademark of Littelfuse,
Inc.

10

ALTEC LANSING^ CORPORATION • a Mark IV Company