Infinity Alpha1200s Subwoofer SM

Alpha 1200s
Powered Subwoofer
SERVICE MANUAL
Infinity Systems Incorporated

250 Crossways Park Dr.
Woodbury, New York 11797 Rev1 4/2004
Alpha 1200s
- CONTENTS -
SPECIFICATIONS ……..………………………………….…………………..1
DETAILED SPECIFICATIONS ……..………………………………………..2
CONTROLS..………………………………. …….………….……..….…...…4
CONNECTIONS..………………………………. …….……………….…...…5
OPERATION..………………………………. …….….….…………….…...…6
BASS OPTIMIZATION SYSTEM..………………..…….…………..….…….7
BLOCK DIAGRAM………...………………………...….…..………..….…….8
BULLETIN INF2004-01..………………………………. …….……….…...…9
EXPLODED VIEW………...……………………………………………….….10
PCB DRAWINGS………...………………………...….…..………..….……..11
ELECTRICAL PARTS LIST ..……………….……….……………..….…….16
INTEGRATED CIRCUIT/TRANSISTOR DIAGRAMS..……………………21
SCHEMATICS …………..…………………………………………………….22
PACKAGE ..………………………………. ………………………..….…..…26
Infinity Alpha 1200s Basic Specifications
Frequency Response 28Hz – 150Hz (±3dB)
Maximum Amplifier Output 500 watts RMS (20Hz – 150Hz with no more than 0.1% THD)
Crossover Frequencies 50Hz – 150Hz, 24dB/octave, continuously variable
Driver 12" (305mm) C.M.M.D.
Dimensions (H x W x D) 17-1/2" x 17-1/4" x 18-1/4"

(445mm x 438mm x 464mm)
Weight 45 lb (20.5kg)
Optional Accessory Bass Optimization Test & Measurement Kit

Infinity Part Number: 335852-002
Infinity continually strives to update and improve existing products, as well as create new ones. The specifications
and construction details in this and related Infinity publications are therefore subject to change without notice.
1
Alpha 1200s
Alpha 1200s Powered Sub/ Plate Amp
LINE VOLTAGE Yes/No Hi/Lo Line Nom. Unit Notes

US 120vac/60Hz Yes 108-132 120 Vrms Normal Operation
EU 230vac/50-60Hz Yes 207-264 230 Vrms Normal operation, MOMS required
QA Test
Parameter Specification Unit Conditions Notes
Limits
Amp Section
Bridge type amplifier, None of the speaker
Type (Class AB, D, other) D n/a n/a terminals must be connected to system GND at
any time.
Load Impedance (speaker) 6 Ohms n/a Nominal
Limiter prevents continuous power to exceed 240
Rated Output Power 275 Watts 220 1 input driven
Watts.
THD @ Rated Power 0.1 % 1 22k filter
THD @ 1 Watt 0.1 % 0.2 22k filter
DC Offset 10 mV-DC 60 @ Speaker Outputs
Measured at the speaker cable. 200 Watts,
Damping factor >50 DF 23 Measured at amplifier board measured at speaker output terminals located at
the amp board.
Input Sensitivity
Input Frequency 30 Hz 30 Nominal Freq.
L&R 446 mVrms ±2dB To 200 Watts Single input driven, Ap Zo=600 Ohms, LP ON
LP Off Mode selected 446 mVrms ±2dB To 200 Watts Single input driven , Ap Zo=600 Ohms, LP OFF
Speaker/Hi Level Input 6.225 Vrms ±2dB To 200 Watts Single input driven, Ap Zo=600 Ohms, LP ON
Signal to Noise
SNR-A-Weighted 100 dBA 85 relative to rated power A-Weighting filter
SNR-unweighted 90 dBr 85 relative to rated power 22k filter
SNR rel. 1W-unweighted 55 dBr 50 relative to 1W Output 22k filter
Volume @max, using RMS reading
Residual Noise Floor 0.5 mVrms 1
DMM/VOM (or A/P)
Volume @max, w/ A/P Swept
Residual Noise Floor 0.5 mVrms(max) 1 Bandpass Measurement (Line
freq.+ harmonics)
Input Impedance
Line Input (L, R,LFE) 10K ohms Nominal
Speaker/Hi Level Input 10K ohms Nominal
Filters
LP 4th order variable 50-150 Hz ± 10
Subsonic filter (HPF) 3rd Orde Fixed Hz ± 10
Low pass filter OFF Fixed Hz ± 10 L or R input driven, LP Filter OFF
BOS
Frequency Control --
Range 20-80 Hz functional 21 detent pot (0.1 oct. steps)
Level Control -- --
Range -14.1 to 0 dB functional 21 detent pot (0.5dB steps)
Width(Q) Control -- --
Range 4.5% to 49.5% octave functional 21 detent pot (5steps/0.1 octave)
Limiter
THD at Max. Output Power YES functional Maximum Output Power
Features --
Auto - On -Off YES -- functional No switch provided, Refer to ATO section
Phase switch 0-180 deg functional
Volume pot Taper (lin/log) LOG -- functional A Taper
Variable crossover 50-150 Hz YES functional 4th Order LP Variable crossover
HP Speaker out YES functional Pass Through from the speaker input section
LP On- Off Select switch YES -- functional Disables LP filter, intended for LFE
Input Configuration
Line In (L,R) & LFE YES -- functional Dual RCA jack
Spkr/Hi Level In YES -- functional Binding post connector L&R
Signal Sensing (ATO)

Auto-Turn-On (yes/no) YES functional Auto - on selection switch in Auto
ATO Input test frequency 50 Hz functional "
ATO Level LFE Input 2 mV functional "
ATO Level Speaker in 50 mV functional "
2
Alpha 1200s
QA Test
Parameter Specification Unit Conditions Notes
Limits
Amp connected and AC on, then
ATO Turn-on time 2 seconds functional
input signal applied
(T) Time before muting, after input
Auto Mute/ Turn-OFF Time 15 minutes 17 Auto turn of time (T) must be 10 > T < 17 Minutes
signal is removed
Power on Delay time 3 sec. 4 AC Power Applied
Transients/Pops
ATO Transient 5 mV-peak n/a @ Speaker Outputs
Turn-on Transient 50 mV-peak 2v-pp @ Speaker Outputs AC Line cycled from OFF to ON
Turn-off Transient 50 mV-peak 2v-pp @ Speaker Outputs AC Line cycled from ON to OFF
Efficiency
Efficiency 70 % 65 Rated power Nominal Line voltage 120 VAC
Maximum allowable input power under nominal
Stand-by Input Power 12 Watts 15 @ nom. line voltage Input voltage and frequency, in stand-by mode
(HOT or COLD operation).
Power Cons. @ rated power 340 Watts 375 @ nom. line voltage 230 Watts @ 6.0 Ohms nominal line voltage
Protection
Amplifier should resume operation after short
Short Circuit Protection YES functional Direct short at output
circuit condition removal
Temperature rise in accessible metal parts should
not exceed 35K rise for domestic version or 30K
Thermal Protection YES functional @1/8 max unclipped Power rise for European versions (refer to requirements
sheet). Unit is protected for over-temperature
conditions
DC Offset Protection YES - DC present at Speaker Out leads Relay or crowbar (for driver/fire protection),
Line Fuse Rating
USA-Domestic 4 Amps Type-T or Slo Blo-250 V
EU 2 Amps Type-T or Slo Blo-250 V Internal fuse with UL/SEMKO rated holder
3
Alpha 1200s
CONTROLS
Rear Panel
BASS OPTIMIZATION SYSTEM
20 80 -14.1 0 4.5 49.5

FREQUENCY LEVEL WIDTH
180 LP ON ON

PHASE GREEN: ON
RED: STANDBY
0 LP OFF OFF POWER

50 150 MIN MAX
CROSSOVER GAIN
®
LINE LEVEL IN
R L Alpha 1200s
CAUTION
RISK OF ELECTRIC SHOCK
R DO NOT OPEN
HIGH
LEVEL
WARNING: TO REDUCE THE RISK OF FIRE OR ELECTRIC SHOCK,
DO NOT EXPOSE THIS APPLIANCE TO RAIN OR MOISTURE.
POWER
IN
L AVERTISSEMENT: POUR PRÉVENIR LES RISQUES D'INCENDIE OU ON

DE CHOC ÉLECTRIQUE, ÉVITER D'EXPOSER CET APPAREIL A LA
PLUIE OU A L'HUMIDITÉ.
OFF
R
NRTL/C
HIGH CSA 22.2

UL1492
LEVEL
OUT
Infinity Systems, Inc.
L Northridge, CA USA
AC
_ + 120V ~ 60HZ
500W
Bass Optimization Controls (see page 5) Phase Switch

Bass Optimization System Selector Low-Pass Filter Selector
Center-Frequency Adjustment Power Indicator
Bass Optimization System Level Adjustment Crossover Adjustment

Bass Optimization System Bandwidth Adjustment Subwoofer Gain (Volume) Control
Line-Level Inputs
High-Level (Speaker) Inputs
High-Level (Speaker) Outputs
Power Switch
INFINITY ALPHA 1200S

4
Alpha 1200s
If your receiver/processor has subwoofer

CONNECTIONS outputs for the left and right channels:
If your receiver/amplifier does not have subwoofer RECEIVER/PROCESSOR
outputs for the left and right channels or an LFE

output:
RECEIVER/AMPLIFIER
Front Speaker Output
20 80 -14.1 0 4.5 49.5

180 ON
PHASE GREEN: ON
RED: STANDBY
0 OFF POWER
50 150 MIN MAX

CROSSOVER GAIN

LINE LEVEL IN

R L
Alpha 1200s
CAUTION
R DO NOT OPEN
HIGH WARNING: "# $%&!% " % $' #( ($% #$ %)%"$ #' POWER
20 80 -14.1 0 4.5 49.5 LEVEL &# #" %*+#% " ++) % "# $ #$ ,#"!$%
FREQUENCY LEVEL WIDTH IN
L AVERTISSEMENT: +#!$ +$-%$ )% $.!% &/%&% #! ON
180 ON &% # -)%"$.!% -"%$ &/%*+#%$ %" ++ $%) )
+)!% #! )/ !,&"-
PHASE GREEN: ON
RED: STANDBY
0 OFF POWER OFF
R
$")0
HIGH
!)12
LEVEL
OUT
50 150 MIN MAX
CROSSOVER GAIN
L !

LINE LEVEL IN
_ +

R L
Alpha 1200s
CAUTION
R DO NOT OPEN
HIGH WARNING: "# $%&!% " % $' #( ($% #$ %)%"$ #' POWER
LEVEL &# #" %*+#% " ++) % "# $ #$ ,#"!$%
IN
L AVERTISSEMENT: +#!$ +$-%$ )% $.!% &/%&% #! ON
&% # -)%"$.!% -"%$ &/%*+#%$ %" ++ $%) )
R
+)!% #! )/ !,&"-
OFF • Set Low-Pass Filter to “On.”

$")0
HIGH
!)12
LEVEL
OUT

L !
_ +

NOTE: Some receivers have a single subwoofer output (do not confuse
this with a single LFE output as described below). In that case, it is
recommended that you use a Y connector (not included) to maximize
performance.
If you have a Dolby* Digital or DTS® receiver/processor

with a low-frequency-effects (LFE) output:
• Set Low-Pass Filter to “On.”
SUBWOOFER OR
LFE OUTPUT
RED = +
BLACK = –
20 80 -14.1 0 4.5 49.5
1. LOOSEN TERMINALS 180 ON

PHASE GREEN: ON
RED: STANDBY
0 OFF POWER
2. INSERT BARE END;

TIGHTEN TERMINALS 50 150
CROSSOVER
MIN
GAIN
MAX
¤
LINE LEVEL IN
R L Alpha 1200s
CAUTION
STRIPE = – NO STRIPE = + R
DO NOT OPEN
HIGH
LEVEL
WARNING: TO REDUCE THE RISK OF FIRE OR ELECTRIC SHOCK,
DO NOT EXPOSE THIS APPLIANCE TO RAIN OR MOISTURE.
POWER
IN
L AVERTISSEMENT: POUR PR VENIR LES RISQUES D’INCENDIE OU ON
DE CHOC LECTRIQUE, VITER D’EXPOSER CET APPAREIL A LA
PLUIE OU A L’HUMIDIT .
OFF
R
NRTL/C
HIGH CSA 22.2
UL1492
LEVEL
OUT
Infinity Systems, Inc.
L Northridge, CA USA
AC
_ + 120V ~ 60HZ
500W
• Set Low-Pass Filter to “Off”.
NOTE: In this case, you do not need to use a Y connector. Simply

connect the LFE output on your receiver/processor to either the left
or right input on the subwoofer.

5
Alpha 1200s
OPERATION
Power On Crossover Adjustments
Plug your subwoofer’s AC cord into a wall outlet. Do not use the The Crossover Adjustment Control determines the highest
outlets on the back of the receiver. frequency at which the subwoofer reproduces sounds. If your main
speakers can comfortably reproduce some low-frequency sounds,
Initially set the Subwoofer Gain (Volume) Control to the
“min” position. set this control to a lower frequency setting, between 50Hz –
100Hz.This will concentrate the subwoofer’s efforts on the
Turn on your sub by pressing the Power Switch on the rear ultradeep bass sounds required by today’s films and music. If you
panel. are using smaller bookshelf speakers that do not extend to the
lower bass frequencies, set the Crossover Adjustment Control to
Auto On/Standby a higher setting, between 120Hz – 150Hz.
With the Power Switch in the ON position, the Power Note: This control will have no effect if the Low-Pass Filter
Indicator LED will remain backlit in red or green to Selector Switch is set to “Off.” If you have a Dolby Digital or
indicate the On/Standby mode of the subwoofer. DTS processor/receiver, the Crossover Frequency is set by the
RED = STANDBY (No signal detected, Amp Off) processor/receiver. Consult your owner’s manual to learn how
to view or change this setting.
GREEN = ON (Signal detected, Amp On)
The subwoofer will automatically enter the Standby mode after Phase Control
approximately 10 minutes when no signal is detected from your
The Phase Switch determines whether the subwoofer
system.The subwoofer will then power ON instantly when a
speaker’s piston-like action moves in and out with the main
signal is detected. During periods of normal use, the Power
speakers, 0˚, or opposite the main speakers, 180˚. Proper phase
Switch can be left on.You may turn off the Power Switch adjustment depends on several variables such as room size,
for extended periods of nonoperation, e.g., when you are away on
subwoofer placement and listener position. Adjust the phase
vacation.
switch to maximize bass output at the listening position.
Adjust Gain
Turn on your entire audio system and start a CD or movie
soundtrack at a moderate level.Turn up the Subwoofer Gain
(Volume) Control about half way. If no sound emanates from
the subwoofer, check the AC-line cord and input cables. Are the
connectors on the cables making proper contact? Is the AC
plug connected to a “live” receptacle? Has the Power Switch
been pressed to the “On” position? Once you have confirmed
that the subwoofer is active, proceed by playing a CD, record or
cassette. Use a selection that has ample bass information.
Set the overall volume control of the preamplifier or stereo to a

comfortable level. Adjust the Subwoofer Gain (Volume) Control
until you obtain a pleasing blend of bass. Bass response should
not overpower the room but rather be adjusted so there is a
harmonious blend across the entire musical range. Many users
have a tendency to set the subwoofer volume too loud,
adhering to the belief that a subwoofer is there to produce lots
of bass.This is not entirely true. A subwoofer is there to enhance
bass, extending the response of the entire system so the bass
can be felt as well as heard. However, overall balance must
be maintained or the music will not sound natural. An
experienced listener will set the volume of the subwoofer so
its impact on bass response is always there but never obtrusive.

6
Alpha 1200s
To solve a problem, it helps to first identify whether you have one
and, if so, what it is. First, play a variety of music and films with
energetic bass sounds, like bass guitar, kick drum, keyboards,
etc. A kick drum should produce a tight “thump” , not a flabby
BASS OPTIMIZATION SYSTEM™ “boom.” Bass melody or harmony lines should have notes that are
about equally loud. If some notes disappear, or stand out
because they are consistently too loud, there is a problem.
Infinity’s Bass Optimization System is a simple-to-use, yet Disappearing notes have to be handled by moving the listening
sophisticated, low-frequency calibration system. Each Interlude position, or the loudspeakers, to slightly different locations.
subwoofer contains a parametric equalizer that you can adjust Often, but sadly not always, this will be enough. Excesses in bass
following the directions below. By following these instructions, tend to be most annoying, and energetic resonances that cause
you can improve the sound of your system. “boomy” or “lumpy” bass can be truly aggravating over a period
of time. Infinity’s Bass Optimization System can fix this.
The Bass Optimization System Goal
So, the first step is to exercise your music collection, and listen
It is a fact of audio that what we hear at low frequencies is
for low-frequency problems that crop up in several different
determined as much or more by the listening room than by the
recordings. Something that only happens in one recording is
loudspeaker itself. Placement of the loudspeakers and listeners
likely to be a problem in the recording – it happens! If you
and the acoustical characteristics of the room surfaces are all
identify something that is consistently wrong, select a record that
important determinants of bass quantity and quality. In most
shows it very clearly, and put your CD/DVD player into a repeat
practical situations, there is little that can be done about this,
mode (A-B repeat is especially helpful, because you can isolate a
except for patient trial-and-error repositioning of the
short musical passage).
loudspeakers and listeners. Usually, the practical constraints of
a living space and the impracticality of massive acoustical
Set the Bass Optimization System Bandwidth Adjustment Control
treatment mean that equalization is the only practical solution.

to a middle position (10 clicks from a fully clockwise
position) and set the Level adjustment for a –6dB (8 clicks
Professional sound engineers routinely employ sophisticated
from a fully clockwise position).Then, while the music is playing,
measurement systems and equalizers to optimize speakers to the
sit in your favorite chair and have somebody else slowly adjust
installation.This was never practical for the home audiophile.
the Center-Frequency control from fully clockwise to fully
This is why the Bass Optimization System was created. It
counter-clockwise. At a certain frequency, you should hear the
enables you to identify the dominant low-frequency response
problem lessen and the overall bass performance improve. When
characteristic of your room. Once you know the problem, the
you are satisfied that you have found the best frequency, have
Bass Optimization System provides the tools needed to optimize
your assistant vary the Level slowly up and down until you
the low-frequency characteristics of the speakers to the room
have maximized the improvement. If you have really keen ears,
they are in, exactly as the professional sound engineers do it.
you can also have the Bandwidth Adjustment control
adjusted
for maximum benefit.
Preparations
Before beginning the bass tests, please check the following: While the Bass Optimization System allows the listener to fine-
• Make sure all three Bass Optimization System controls on the tune the bass response to sound best in a particular room, some
subwoofer are turned fully clockwise. listeners don’t have the skill or desire to adjust their system by
• Make sure the loudness contour (if any) on your receiver/ ear. In order to facilitate quicker and more accurate results,
processor/preamp is turned off. Infinity has developed an optional test and measurement kit that
• Set the receiver’s/processor’s tone controls (Bass and Treble) allows the user to perform a series of measurements and aids
to their center or flat positions. him/her in properly setting the Bass Optimization System
• Bypass all surround and effects features of your receiver/ controls. With the addition of this kit, the Bass Optimization
processor/preamp or set to Stereo Bypass. System becomes truly room-adaptive.The kit consists of the
• If you are using a multichannel surround processor or following: a test CD, a sound-level meter that is specifically
receiver, make sure all bass-management features are properly calibrated for low frequencies, and something we call a “Q-Finder,”
set.The Audio channels should all be set to “Small” or “High- a device to help find the width of the measured curve and,
Pass” and the subwoofer set to “On.” finally, a measurement template. It works as follows.The listener
• Set the Bass Optimization System Selector to “On.” plays the tones from the test CD and records the relative output
level of each test tone, using the sound-level meter, on the
For best results, it is recommended that all major furnishings provided measurement template. After all the tones are complete,
are in place and that all doors and windows in the listening the template contains a response curve for the frequencies
area are in their normal positions.That is, if you normally listen below 100Hz.The user simply notes the frequency of the largest
to music with all doors closed, then this is how they should be bass peak, calculates the correct amount of attenuation, and
during this procedure. uses the “Q-Finder”to determine the width of the curve.These
three values are dialed into the Bass Optimization System
controls located on the speaker.The entire process takes less
than twenty minutes.
If your dealer does not stock the Bass Optimization System test
and measurement kit, you may purchase it directly from Infinity.
U.S. residents can visit our Web site at www.infinitysystems.com
or call 1.800.553.3332. Canadian residents should contact their
dealer or call 1.800.567.3275.
7
Alpha 1200s
8
Alpha 1200s
Service Bulletin
Service Bulletin INF2004-01 – March 2004 This is considered a Minor repair
To: All Infinity Service Centers
Model: Alpha 1200s
Subject: Distortion When Coming Out Of Standby
In the event you receive an Alpha 1200s subwoofer with the complaint “There is a brief chirping
sound, or short oscillation that occurs when the unit is in the AUTO mode, in Standby, when it’s
triggered ON with a music signal”, follow the procedure below to correct this condition:
Synopsis: Replace D60 (RLS4148 diode) with a 3.6V Zener Diode; add new Resistor.
1) Remove the amplifier assembly from the subwoofer cabinet (12 Phillips screws).
2) Remove the Plastic Amp Cover from the faceplate (4 Phillips screws).
3) The area of concern is on the Class D Driver PCB (Small Upright PCB on the MAIN AMP PCB). A long,
thin, soldering iron tip is recommended. Care must be taken not to damage surrounding components, like
large inductor pair L8.
4) Locate, remove D60 (RLS4148 diode); replace with a 3.6V zener diode, Infinity Part# ZMM5227BCT-ND.
When replacing D60 the polarity of the new (zener) diode should be reversed.
5) Add new 27KΩ resistor, Infinity Part# 299-27K, to the indicated connections. (This component,
electrically, will be in parallel with R37, reducing its value to <22KΩ). Assure the leads do not come into
contact with any other connections; insulate the leads if necessary.
6) Replace amp cover and return amplifer assembly to cabinet.
7) Test the subwoofer to assure the distortion is no longer present.
9
Alpha 1200s
EXPLODED VIEW
Alpha 1200s Amplifier - Not For Sale
Alpha 1200s Cabinet - Not For Sale
7 (12)
3 (4)
1
5
7 (6)
6 (4)
Alpha 1200s
ITEM ITEM
NO. DESCRIPTION QTY. PART NO. NO. DESCRIPTION QTY. PART NO.
1. Woofer, 12," C.M.M.D.™, Shielded, 1 336056-001 7. Screw Torx HD, 3.9 x 30mm 18 9412730
3.4 ohms ±10% (12 Amp Assembly and 6 Woofer)
2. Front Grille 1 339945-001 8. Spike Foot Kit 1 338076-001
3. Grille Retainer 4 9330070 9. Outer Carton 1 350613-001
4. Port Tube 1 336799-001 10. Top and Bottom End Pads 2 350615-001
5. Trim Ring 1 339944-001 11. Owner’s Manual 1 350614-001
6. Rubber Foot Ass’y 4 338037-001 12. Warranty Card 1 335841-002
10
Alpha 1200s
11
Alpha 1200s
12
Alpha 1200s
13
Alpha 1200s
14
Alpha 1200s
15
Alpha 1200s
Alpha 1200s Electrical Parts List
Part Number Description Reference Designator
AMP ASS'Y
Resistors
021-100401-020 MOF Resistor 1K 1W J FK TYPE R173

021-560305-020 MOF Resistor 560R 5WS J 8x25 KINK R76
022-005105-020 Cement Resistor PN:SQM 0R05 5W J 25x13 R2
022-470307-020 KNP Resistor 470R 7W J (KNP-700S) R78
024-000098-120 SMD Resistor 0R 1/8W J 0805 R8
024-100498-120 SMD Resistor 1K 1/8W J 0805 R110,169
024-100598-120 SMD Resistor 10K 1/8W J 0805 R5,7,16,118,121,122,125,126
024-150498-120 SMD Resistor 1K5 1/8W J 0805 R119
024-160598-100 SMD Resistor 16K 1/8W F 0805 R13,13B
024-220598-120 SMD Resistor 22K 1/8W J 0805 R127
024-330498-120 SMD Resistor 3K3 1/8W J 0805 R77,79
024-330598-120 SMD Resistor 33K 1/8W J 0805 R4,6,14,60,60B
024-470298-120 SMD Resistor 47R 1/8W J 0805 R24-27
024-470398-120 SMD Resistor 470R 1/8W J 0805 R145,155,177,186
024-510498-120 SMD Resistor 5K1 1/8W J 0805 R48A,48B,48C,48D,48E
025-010300-000 Thermister TSE-103 K L:50mm TH1
Capacitors
031-100184-100 SMD Capacitor 0u01/250V K 0805 X7R C104,119

031-100244-100 SMD Ceramic Cap. 0u01/50V K 0805 X7R C27,28
031-100344-100 SMD Capacitor 0u1/50V K 0805 X7R C10,69,112,115,135,138
031-100384-100R SMD Capacitor 0u1/250V K 1206 X7R C5,6
031-470144-101 SMD Capacitor 0u0047/50V K 0805 X7R C1G1
032-100484-200 END Mylar Cap. 1uF/250V K P:15mm C37,39,30
033-330444-270 NPE Capacitor 3u3/50V K10 (R)8x13 SBE C114,137
033-680464-270 NPE Capacitor 6u8/100V K10 (R)1020 GNE C113,136
034-100614-300 Electrolytic Cap. 100uF/16V M (R)0611 P:2.5 C8
034-100625-300 Electrolytic Cap., 100uF/25V M (R)6.3x11 P:5 C62
034-100695-300 Electrolytic Cap. 100uF/63V M (R)1012 P:5 C142
034-100895-204 Electrolytic Cap. 10000uF/63V M R30x51 85deg C1,4
034-220525-300 Electrolytic Cap., 22uF/25V M (R) 5x11 P:2.5 C25,26
034-330625-300 Electrolytic Cap., 330uF/25V M (R)1013 P:5 C11,100
034-470415-300 Electrolytic Cap, 4u7/50V M (R)0511 P:2.0 C7
Semiconductors
051-000600-100 NPN Transistor PN:MPSW06RLRA TO-92 (ON) Q6

051-005600-100 PNP Transistor PN:MPSW56RLRA TO-92 (ON) Q8
051-290700-100 PNP Transistor PN:P2N2907A TO-92 (ON) Q12,14,16,18
051-540101-000 PNP Transistor PN:2N5401 TO-92 Q3
051-640001-000 MOSFET N-Channel PN:IRF640N TO-220 (IR) Q11,13,15,17
052-400080-000 Bridge Regulator PN:RS804 400V,8A BR1
053-257400-100 IC;DIP,Regulator PN:LM2574 HVN-15V 8PIN (NS) U6
054-000100-100 SMD DIODE PN:ES1D 200V 1A D1,23,37,40,44,47
054-001002-100 SMD ZENER DIODE PN:BZX84C10 10V SOT-23 D32
054-001501-100 SMD ZENER DIODE PN:BZX84C15 15V SOT-23 D2,3
16
Alpha 1200s
054-033904-100 SMD Transistor PN:MMBT3904LT1 SOT23 (ON Q25,28,29

054-033906-100 SMD Transistor PN:MMBT3906LT1 SOT23 (ON Q26,27,30
054-050601-100 SMD ZENER DIODE PN:BZX84C5V6 5.6V SOT-23 C36 D30
054-414803-100 SMD DIODE PN:LL4148 (Wishay) D4-6,13,14,21,22,31,33,38
054-540100-100 SMD Transistor PN:MMBT5401 LT1 SOT-23 Q1
054-555100-100 SMD Transistor PN:MMBT5551 LT1 (ON) Q2
Miscellaneous
043-300101-000 INDUCTOR 30uH YT-10033 L9,10

043-560200-000 INDUCTOR 56uH YT-10779 L12
043-700100-000 INDUCTOR 70uHx2 YT-10024 L8
043-820300-000 INDUCTOR 820uH YT-10034 L1
044-100100-000 SMD FERRITE BEAD PN:321611 600R/100MHz 1206 FB1,FB2
072-040039-000 Terminal PCB type PC205 (t=0.8m/m) T205MA T1
072-040064-000 Terminal PCB type PC250(t=0.8),T250MA T2,TER6
072-040096-000 Terminal T187MA(PCB TYPE) (t=0.8mm) PC187(0.8) TER5,TER7
072-040250-000 CONNECTOR 7 PIN JS-1001-7 P:2.5mm P1
073-111003-000 Shorting Strap 54.9x13.6x1m/m J7
073-111004-000 Shorting Strap 29.5x12.4x0.8m/m J4,9
074-300018-000 RELAY PN:943-1C-48D RLY1
INPUT PCB ASS'Y (3 PCB's)
Resistors
021-226598-100 MF Resistor 22K6 1/8W F R214

021-576498-100 MF Resistor 5K76 1/8W F R204
024-100598-101 SMD Resistor 10K 1/8W F 1206 R200B,201B,218B,219B
024-100598-121 SMD Resistor 10K 1/8W J 1206 R202,205-207,212,217
024-100698-101 SMD Resistor 100K 1/8W F 1206 R200,201,218,219
024-226598-100 SMD Resistor 22K6 1/8W F 1206 R208,209,231,232
024-330498-101 SMD Resistor 3K3 1/8W F 1206 R203,215
024-470798-121 SMD Resistor 4.7M 1/8W J 1206 R243,244
024-620398-121 SMD Resistor 620R 1/8W J 1206 R221,226
024-750798-121 SMD Resistor 7M5 1/8W J 1206 R241
026-500595-254 VR 50KA P/N:RK163111R405-EJ R216
026-500595-267 VR 50KBx4 PN:RD1631411001D-50KBx4 (EJ) R233
17
Alpha 1200s
Capacitors
031-100244-101 SMD Capacitor 0u01/50V K 1206 X7R C12,13,224

031-100344-102L SMD Capacitor 0u1/50V K 1206 X7R C227,229,230,232-235
031-100344-104 SMD Capacitor 100pF/50V K NPO 1206 C204,222
031-220244-103L SMD Capacitor 0u022/50V K 1206 X7R C202
031-220344-103 SMD Capacitor 220pF/50V K NPO 1206 C200,210,215,216
031-470444-101 SMD Capacitor 4700pF/50V K X7R 1206 C2G1
031-680444-100 SMD Capacitor 6800pF/50V K X7R 1206 C212
034-100515-300G Electrolytic Cap., 10uF/16V M (R)0511 P:2 C220
034-100615-301 Electrolytic Cap., 100uF/16V M (R)0611 P:5 C221
034-220516-301 Electrolytic Cap. 22uF/16V M (R)0511 P:2 C223,225
035-330293-300 ESK Cap. 0u033/63V J P:5 C209,218
035-560393-300 PE Cap. 0u56/63V J P:5 C207,208
035-680253-300 PE Cap.FE-M 0u068/63V J P:5m/m C201,213
035-680353-300 ESK Cap. 0u68/63V J P:5 PN:ESK063P68JA C214
Semiconductors
050-505200-001 LED PN:LT-2402-21 LED1

054-007200-100 SMD IC PN:TL072CDR SO-8 (TI) U200-205
054-033904-100 SMD Transistor PN:MMBT3904LT1 SOT23 (ON Q203,204
054-050601-100 SMD ZENER DIODE PN:BZX84C5V6 5.6V SOT-23 TAPI D210
054-211400-100 SMD Transistor (NPN) PN:DTC114EK SMT3 (ROHM) Q202
D200-205,207,209,212,216,
054-414803-100 SMD DIODE PN:LL4148 (Wishay)
217,218
Miscellaneous
072-010058-000 RCA JACK 2P PN:0502000W1G (Red,White) J201

072-040039-000 Terminal (PCB TYPE) PC205 (t=0.8m/m) T205MA C211
072-040250-000 CONNECTOR 7 PIN JS-1001-7 P:2.5mm P2,3
072-040253-000 HEADER Right Angle PN:211-103-000-400 3PIN M3
072-060219-000 BINDING POST (gold plated) PN:A807A-RB 8PIN 1/2K red+blk J200
073-010021-000 Screw holder PN:PCB-2(M3) 4PIN T1,2,3
074-030002-000 Toggle Switch P/N L101 SW200-202
RABOS PCB ASS'Y
Resistors
021-100398-100 MF Resistor 100R 1/8W F R339

021-100498-100 MF Resistor 1K 1/8W F R363,381
021-100598-100 MF Resistor 10K 1/8W F R338,342,343,346,348,353
021-100798-100 MF Resistor 1M 1/8W F R356
021-100898-100 MF Resistor 10M 1/8W F R362
021-110698-100 MF Resistor 110K 1/8W F R347
021-121598-100 MF Resistor 12K1 1/8W F R354,369
021-140598-100 MF Resistor 14K 1/8W F R380
021-150198-100 MF Resistor 1K5 1/8W F R341
021-162398-100 MF Resistor 162R 1/8W F R384
021-267498-100 MF Resistor 2K67 1/8W F R336
021-340398-100 MF Resistor 340R 1/8W F R357,371
021-357498-100 MF Resistor 3K57 1/8W F R335
18
Alpha 1200s
021-549398-100 MF Resistor 549R 1/8W F R344

021-590498-100 MF Resistor 5K9 1/8W F R382
021-619498-100 MF Resistor 6K19 1/8W F R359,374
021-680398-100 MF Resistor 680R 1/8W F R360
021-698598-100 MF Resistor 69K8 1/8W F R383
021-787398-100 MF Resistor 787R 1/8W F R350,364
021-909398-100 MF Resistor 909R 1/8W F R385
021-931498-100 MF Resistor 9K31 1/8W F R351
026-100595-346 VR 10KAx2 (Level,Width) PN:RV16A01-20-15K-A14-3E53 VR302,303
026-100595-347 VR 10KCx2 (Frequency) PN:RV16A01-20-15K-C14-3E53 VR301
Capacitors
031-100345-300 SMD Capacitor 0u1/50V M 1206 X7R C305,306

035-100293-300 ESK Mylar Cap. 0u01/63V J P:5 in parallel with C328
035-100363-300 PE Cap. 0u1/100V J P:5m/m C322,323,328
035-680253-300 PE Cap. FE-M 0u068/63V J P:5m/m C381
038-150393-300 MPE Cap. P:5 0u15/63V J C380
Semiconductors
054-007200-100 SMD IC PN:TL072CDR SO-8 (TI) U301

054-007400-100 SMD IC;(OP) PN:TL074CDR (TI) U300
072-040250-000 CONNECTOR 7 PIN JS-1001-7 P:2.5mm P4
FUSE PCB ASS'Y
039-220180-100 X2 Safety Cap. 0u22/250V 18x16.5x8.5mm PN:XG275M224VHCXAC1

043-324300-000 INDUCTOR 324uH YT-10778 L13
072-040064-000 Terminal (PCB TYPE) PC250(t=0.8),T250MA TER2
072-040096-000 Terminal T187MA(PCB TYPE) (t=0.8mm) PC187(0.8) TER1,3,4
073-050001-000 FUSE CLIP P/N:CFFH1206 F1,B1
091-000128-000 FUSE T4A/250V φ5x20m/m
PRE DRIVER AMP PCB
Resistors

024-100498-120 SMD Resistor 1K 1/8W J 0805 R81,85,96,97,131,137,142
024-100598-120 SMD Resistor 10K 1/8W J 0805 R75,82,83,92,98,132,133
024-100798-120 SMD Resistor 1M 1/8W J 0805 R32,33
024-220398-120 SMD Resistor 220R 1/8W J 0805 R136,167
024-220798-120 SMD Resistor 2M2 1/8W J 0805 R87,93
024-270498-120 SMD Resistor 2K7 1/8W J 0805 R80,84,157
024-470498-120 SMD Resistor 4K7 1/8W J 0805 R151-153,183,34,36
19
Alpha 1200s

024-680498-120 SMD Resistor 6.8K 1/8W J 0805 R135,166
Capacitors
031-100244-100 SMD Ceramic Cap. 0u01/50V K 0805 X7R C108,118,131,140

031-100343-100 SMD Capacitor 100pF/50V J 0805 NPO C81,84
031-100344-100 SMD Capacitor 0u1/50V K 0805 X7R C75-78,82,85
031-180344-100 SMD Capacitor 0u18/50V K 0805 X7R C80,83
031-470244-102 SMD Capacitor 0u047/50V K 0805 X7R C93,94,101,124
031-560243-100 SMD Capacitor 56pF/50V J 0805 NPO C92,102,105,125
031-560343-102 SMD Capacitor 560pF/50V J 0805 NPO C79
034-100625-303 Electrolytic Cap. 100uF/25V M (R) P:2.5 C117
034-100715-202 Electrolytic Cap. 85 deg 1000uF/16V M (R) 10x17 P:5 C109,132
034-330615-301 Electrolytic cap. 330uF/16V M (R)0812 P:3.5 C32
Semiconductors
051-000600-100 NPN Transistor PN:MPSW06RLRA TO-92 (ON) Q31

051-222200-100 NPN Transistor (ON SEM) PN:MPS2222ARLRA TO-92 Q20,22
051-555100-000 NPN Transistor PN:2N5551 TO-92 Q21,23
053-211100-000 IC;DIP,DRIVER PN:IR2111 8PIN (IR) U7,8
054-000100-100 SMD DIODE PN:ES1D 200V 1A D35,43
054-001002-100 SMD ZENER DIODE PN:BZX84C10 10V SOT-23 D42,49
054-007200-100 SMD IC PN:TL072CDR SO-8 (TI) U9,10
054-033906-100 SMD Transistor PN:MMBT3906LT1 SOT23 (ON Q34,35
054-050601-100 SMD ZENER DIODE PN:BZX84C5V6 5.6V SOT-23 TAPI Z7,8
054-414803-100 SMD DIODE PN:LL4148 (Wishay) D36,39,46,52,60,61
054-540100-100 SMD Transistor PN:MMBT5401 LT1 SOT-23 Q33,40
054-555100-100 SMD Transistor (NPN) PN:MMBT5551 LT1 (ON) Q32
Miscellaneous
072-040229-000 HEADER Right Angle PN:211-107-000-400 7PIN PIN2

072-040230-000 HEADER Right Angle PN:211-111-000-400 11PIN PIN1
008-060302-032 GASKET (S12P) CR 28x20mm t=5mm C4305 X'FORMER
008-061215-000 GASKET C4305 12x15 t=5mm CR Thermister
008-062001-000 GASKET CR C4305 196x10mm t=1mm COVER(front)x2,COVER(Rear)x2
008-063001-000 GASKET CR C4305 320x10mm t=1mm COVER(Front)x2,COVER(Rear)x2
042-014107-001 Transformer 120V/60Hz EI-125 YT-9313-2
061-001052-000 Knob PN:49001-W (18)D=15.1 H=14.5 For R233,216,VR301-303
061-100016-000 Partition post PN:BCMS-8 L=8mm NY 66(UL) Power PCB
061-314002-000 Strain Relief P/N SB4F-2 PANEL,COVER
061-700035-000 Thermal Isolator PN:TO-220AWO For Q11,15
061-700044-000 Mica 13x18mm TO-220 For Q13,17
063-010010-000 Bracket for Transistor P/N:TRK-2 For Q11,13,15,17,TH1
063-332101-000 Amp Cover 12.83"x8.33"x3.93" ABS 94V0
063-332103-000 PANEL(ALPHA SUB 1200) 12.83x8.33" t=0.984"SPCC
065-040102-090 UL PVC sleeve 300V 105deg φ1mm blk
073-014044-000 Bracket black 6.64"x3.50"x3.20" SPCC cadium
074-020018-000 ROCKER SW (POWER) PN:RF1003-BB4-0
086-021836-000 Power Cord SPT-2 #18 12'+T187
181-911622-148 Wire #16AWG UL1007 red L=720 T250 terminal + sleeve SPE+
181-911800-338 Wire #18AWG UL1007 blk L=110mm+7mm C211
181-921600-000 BLK Wire #16 UL1015 T187 transparent sleeve L:140mm
181-921699-000 WHT Wire #16 UL1015 T187 transparent sleeve L:160mm
20
Alpha 1200s
21
Alpha 1200s
HARMAN
P1A NEW Design 350089-001
P1B CHANGE:R119,R224,R254 ALPHA-SUB-1200
P1C CHANGE:R76,R244,R249,R254,C221 DEL:D218,R264 ALPHA-SUB-1200-P1F
P1D CHANGE:C224 ALPHA-SUB-1200
P1E CHANGE:R78,R119 2002/09/16
P1F CHANGE:R32,R33,R249,C323,C328 ADD:D218,R264 22 1 of 4 P1F
BELLE
Alpha 1200s
HARMAN
P1E CHANGE:R78,R119 2002/09/16
BELLE
Alpha 1200s
HARMAN
P1E CHANGE:R78,R119 2002/09/16
BELLE
Alpha 1200s
HARMAN
P1E CHANGE:R78,R119 2002/09/16
BELLE
Alpha 1200s
PACKAGING
Legend on Page 9 11 12 8
10
Item Description Part number Qty.

Alpha 1200s
8. Spike Foot Kit 338076-001 1

9 Outer Carton 350613-001 1
10. Top and Bottom End Pads 350615-001 2
11. Owner’s Manual 350614-001 1
12. Warranty Card 335841-002 1 10
26

Infinity Alpha1200s Subwoofer SM

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Infinity Alpha1200s Subwoofer SM

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Alpha 1200s

Infinity Systems Incorporated

Infinity Alpha 1200s Basic Specifications

Frequency Response 28Hz – 150Hz (±3dB)

Crossover Frequencies 50Hz – 150Hz, 24dB/octave, continuously variable

Driver 12" (305mm) C.M.M.D.

Dimensions (H x W x D) 17-1/2" x 17-1/4" x 18-1/4"

Optional Accessory Bass Optimization Test & Measurement Kit

LINE VOLTAGE Yes/No Hi/Lo Line Nom. Unit Notes

Signal Sensing (ATO)

Power on Delay time 3 sec. 4 AC Power Applied

BASS OPTIMIZATION SYSTEM

20 80 -14.1 0 4.5 49.5

Bass Optimization Controls (see page 5) Phase Switch

High-Level (Speaker) Inputs

High-Level (Speaker) Outputs