GENERAL INFORMATION.........................................................................................................................................2
PA635X PANEL AND FEATURE DESCRIPTIONS .................................................................................................... 3
INSTALLATION
Physical Location and Mounting............................................................................................................................5
CONNECTING THE PA635X......................................................................................................................................6
To enhance the ease of installation and obtain optimum performance from the PA635X, we recommend that you first
become familiar with all its features and special capabilities by studying the descriptions and instructions in this
manual.
The PA635X was designed to meet the audio power amplifier needs of custom installed multi-zoned systems with
high sonic quality. It's 6-5-4-3 multi-channel capability permits a wide variety of other uses as well, such as surround
sound home theater applications. Specific features and technology are as follows:
Cost/Size Efficiency. The PA635X features six 35-watt power amplifiers. This permits each PA635X to drive 3zones in a multi-zone system -- each with a 35-watt stereo amplifier per zone. The rack-mount design, plus multiple
amplifiers in a single package, delivers high quality at a reasonable price.
Input Level Flexibility. The input levels are indiv idually adjustable (per stereo pair) from a low of 0.2 volts up to 3
volts. This gives the installer the ability to adjust the overall gain of the system or zone. For instance, there may be a
need to adjust the amplifier to deliver a controlled, maximum sound level into a zone when the volume control on the
preamp is set to maximum. This would act as a volume limiter for any particular zone (i.e. to prevent the kids from
over-driving wall speakers, etc.).
3
PA635X
SIX CHANNEL AMPLIFIER
POWER
1
2
FIGURE 1 – THE MODEL 635X
6-5-4-3 Output Flexibility. Each pair of amplifiers can be bridged to allow several channel and power output
capabilities. It can be configured into four power packages as follows Which gives the PA635X added use in many
other applications, such as driving surround sound speaker systems:
• Six 35-watt amplifiers.
• One 70 and four 35-watt amplifiers.
• Two 70 and two 35-watt amplifiers.
• Three 70-watt amplifiers.
Low Impedance Capability. Each amplifier is 4-Ohm safe under music conditions in stereo mode and 8-Ohm safe
when bridged. This means, for instance, that you can drive two pairs of 8-Ohm speakers in stereo mode in each zone
with ease.
Auto Protection Circuit. Protects the PA635X if a short or very low impedance is detected at the speaker terminals.
Each amplifier pair is protected separately, with an LED indicator showing which pair is in protection. Normal
operation is restored automatically within 3 to 4 seconds after the short is removed.
Remote Master ON/OFF Control Jack. This jack allows the PA635X to be powered on and off by a positive DC
voltage ranging between 4 and 30 volts (11mA @ 12 V). Specifically, it permits the 12 volt common CO (Control
Output) or zone STATUS outputs from the Xantech ZPR68 to power one or more PA635X's ON and OFF
automatically with zone ON/OFF commands.
1. Front Panel. 19" X 3 1/2" panel designed for mounting into a standard 19" Rack Panel.
2. Rack Panel Handles.
21
3
3
PA635X
SIX CHANNEL AMPLIFIER
POWER
1
1
2
2
3
4
2
FIGURE 2 – THE MODEL PA625X FRONT PANEL – FEATURES AND FUNCTIONS
5
55777
14
8
WARNING
: TO REDUCE THE RISK OF
FIRE OR ELECTRICAL SHOCK, DO NOT
EXPOSE THIS UNIT TO RAIN, MOISTURE
OR PLACE WATER FILLED OBJECTS ON
THE PRODUCT.
ATTENTION
: RISQUE DE CHOC ELECTRIQUE
NE PAS OUVRIR.
NO USER SERVICABLE PARTS INSIDE.
REFER TO OWNERS MANUAL FOR SAFETY INSTRUCTIONS.
ATTENTION
: POUR UN REGLAGE
CORRECT, SE REPORTER AU MANUEL
DINSTRUCTIONS.
MODEL PA635X
GROUND
REMOTE
MASTER
ON/OFF
CONTROL
5-30 VOLTS DC
+--
11
THIS DEVICE COMPLIES WITH
PART 15 OF THE FCC RULES.
OPERATION IS SUBJECT TO
THE FOLLOWING TWO
CONDITIONS: (1) THIS DEVICE
MAY NOT CAUSE HARMFUL
INTERFERENCE, AND (2) THIS
DEVICE MUST ACCEPT ANY
INTERFERENCE RECEIVED,
INCLUDING INTERFERENCE
THAT MAY CAUSE
UNDESIRED OPERATION.
10
LEFTRIGHT
1
1V
LEVEL
3V
SPEAKER
LEFT RIGHT
LEFTRIGHT
MODE
STEREO
MONO
BRIDGED
.2V
USE CLASS 2
WIRING FOR
+-- --+
LOUDSPEAKERS
2
1V
LEVEL
3V
+ BRIDGED -- + BRIDGED --
SPEAKER
LEFT RIGHT
.2V
+-- --+
MODE
STEREO
MONO
BRIDGED
WARNING
TURN POWER
OFF BEFORE
CHANGING
MODES
LEFTRIGHT
3
1V
LEVEL
3V
+ BRIDGED --
SPEAKER
LEFT RIGHT
FUSE
6.25 AMP
666
AC 120V 60Hz
5.5A 660 WATTS
CAUTION
NEUTRAL
FUSING
SLOW BLOW
AC LINE
ON/OFF
1399912
MODE
STEREO
MONO
BRIDGED
.2V
+-- --+
FIGURE 3 – PA635X REAR PANEL - FEATURES AND FUNCTIONS
3. POWER SWITCH When pressed to the IN position, power is applied to the PA635X [provided the rear panel
master AC LINE ON/OFF Switch, item #13, is placed in the ON (I) position]. This is the MANUAL ON position.
When pressed again, it releases to the OUT position (MANUAL OFF), turning the unit OFF.
In addition, this switch must be left in the MANUAL OFF (OUT) position to permit an external DC Control Voltage
to power the PA635X ON and OFF. Refer to "REMOTE MASTER ON/OFF CONTROL" terminals, item #10.
NOTE: The PA635X may also be powered ON/OFF with an external AC line switch into which the power cord of
the PA635X is plugged (such as the switched AC outlet of a preamp, timer, etc. with a 5A minimum rating). For
this type of operation, leave the POWER switch depressed to the MANUAL ON position.
4. Status LED Indicators. These indicators, one for each channel pair, provide the following status information:
• They show Power ON/OFF and Standby ON/OFF conditions.
• They flash Amber 5 times during power up, then turn steady Green when Power On Mute releases. This
action occurs whether the unit is powered ON by the POWER switch (item # 3) or by a DC voltage applied to
the REMOTE MASTER ON/OFF CONTROL terminals (item #10). Be sure the rear panel master AC LINE
ON/OFF Switch, item #13, is set to the ON (I) position for the above to occur.
5. Line Inputs. These RCA-type jacks are the audio inputs for each of the amplifier pairs. Connect them to the
OUTPUT jacks of the driving preamp with good quality RCA-type patch cables. Note that the inputs are marked
LEFT-1-RIGHT, LEFT-2-RIGHT, etc., signifying the stereo channel pairs. Both the LEFT and RIGHT jacks are
also active when the MODE switch (item #7) is set to the MONO or BRIDGED mode.
6. Input LEVEL Control. This screwdriver adjustable control (for each stereo or bridged pair) allows the input level
for full rated power output to be adjusted over a range of 0.2 volts to 3 volts (24.3 dB). Normally you would adjust
the driving preamp to max. v olume, then set this control to the maximum volume that the client desires for a given
zone or room. This prevents the system from being driven to potentially destructive power levels.
7. MODE Switch. Switches the amplifier pair between STEREO, MONO and BRIDGED modes.
a) In STEREO mode, the two amplifiers operate independently of each other for 35 Watts of output each, except
IR control of Volume, Max-V, Mute, Standby OFF/ON and Balance functions is common to both.
b) In MONO mode, left and right input signals are summed internally for Mono output from each of the two
amplifiers. Also, either the Left or Right (item #5) input may be used if the source is already a Mono signal.
c) In BRIDGED mode, the two amplifiers are bridged for a single channel of high power output (150 W atts @ 8
Ohms). Either the Left or Right input (item #5) may be used to drive the resultant single channel amplifier.
CAUTION: Be sure to have the POWER turned OFF when changing the position of this switch and when making
the corresponding speaker connection changes (see also item #9, following).
8. FUSE. When required, replace only with a fuse of the same type and rating:
• 120 V Version: 6.25 AMP 250 VAC, SLOW BLOW.
• 240 V Version: 3.15 A Time-Lag 250 VAC.
• Replacement with a fuse of higher rating will not protect the amplifier and will void the warranty.
9. SPEAKER Terminals. These plug-in 4-terminal screw type connectors permit speaker wire sizes up to 12
gauge. When making connections for the STEREO mode, be sure to observe the "+” and "–" polarity markings,
just under the LEFT & RIGHT markings, for each wire pair going to the speakers.
CAUTION: When making connections for the BRIDGED mode, remember, only one speaker is being attached
per amplifier pair. Be sure to observe the outer "+” and "–" polarity markings on each side of the word
"BRIDGED" on the panel above the 4-terminal connector when connecting the 2-conductor wire to the speaker.
10. REMOTE MASTER ON/OFF CONTROL. This 2-terminal connector allows the entire PA635X to be powered ON
and OFF by a control voltage ranging between 5 and 30 Volts DC (16mA @ 12 V). Be sure to observe the
marked polarity. For instance, the 12 volt common CO (Control Output) of the Xantech ZPR68 preamp will power
the PA635X ON and OFF automatically with the first zone ON and last zone OFF commands. The DC Voltage
must be applied continuously to retain the ON condition and drop to less than 0.5 Volt to switch to the OFF
condition.
NOTE: The front panel POWER switch (item #3) must be left in the Manual OFF (Out) position and the
Master AC Line Switch (item #13) set to ON (I) to permit the REMOTE MASTER ON/OFF CONTROL to
operate. See also CAUTION notes, Fig. 9.
NOTE: When powering up multiple PA635X’s, a delay of two (2) or more seconds should be incorporated
11. Rear Panel ON/OFF LED. This LED indicates the power ON/OFF condition of the entire PA635X, whether
activated by a REMOTE MASTER ON/OFF CONTROL voltage (item #13) or from the front panel POWER switch
(item # 3).
12. Grounding Screw. Provides a means for chassis connection to earth ground or to other A/V products to aid in
the reduction of system noise, etc., where needed.
13. Master AC LINE ON/OFF Switch. Turns power OFF to the entire PA635X, regardless of front panel POWER
switch conditions. Must be placed in the ON (I) position for the other power switching functions to work.
14. 3-Conductor AC Line Cord Receptacle. Standard IEC male receptacle for plug-in of a 3-conductor power line
cord. Depending on the application, plug the line cord into a switched or un-switched 120V 60 Hz AC outlet (or
240 VAC 50 Hz on the 240 V version).
INSTALLATION - PHYSICAL LOCATION AND MOUNTING
Upper shelf, component, wall, etc.
2-inch spacing
PA635X
Keep perforations on top cover free of
obstructions for max. cooling effect.
(minimum)
To maximize air flow, route
single large opening in lower shelf.
Figure 4 – HORIZONTAL MOUNTING
When you mount the PA635X, you should plan its location carefully. Pay close attention to each of the following
factors:
1. The amplifier is convection cooled. That is, it depends on the natural free flow of air up through the slot
perforations in the bottom plate, over the internal heat dissipating fins, then out the top cover, for adequate
cooling.
2. If mounted in an equipment cabinet or other confining location, allow at least 2 inches of space above the top
cover (see Fig. 4). Be sure there are large openings in the shelf below the unit and in the cabinet to allow the
entry of cool air and the escape of warm air.
NOTE: Do not remove feet in shelf-top installations.
3. If the cabinet contains other heat generating components or you are using several PA635X's in a large multi-zone
system, you will have to pay even closer attention to adequate ventilation.
Keep perforations on bottom
plate free of obstructions.
Page 6 Model PA635X
4. Do not hesitate to use fans (quiet, boxer type), if necessary, to ensure a constant flow of air through the PA635X's
and the other heat generating components.
5. When mounting in a 19" (483mm) rack, adding a single RU (Rack Unit) above and below the PA635X will improve
convection in heavy use applications.
[One Rack Unit size = 1-3/4" (44.5mm) in height].
6. In multi-zone installations, you will have large bundles of wire and cable to accommodate audio, video and
speaker connections. Be sure to allow enough room for the leads and dress them in such a manner so as not to
block airflow.
7. The PA635X is designed for mounting into standard 19" Rack Panels or on flat horizontal surfaces. W hen
mounting into a 19" rack, use the rack panel cup washers and screws supplied.
NOTE: You should consider some sort of rear support for rack mounted units when used in mobile applications
or when located in seismically-active areas.
CONNECTING THE PA635X
Preamp Outputs
ZPR68, etc.
RCA Type
Patch Cords
1
Set MODE
Switch to
STEREO position
PA635X
Rear Panel
VIDEO
L
AUDIO
R
LEFTRIGHT
1
MODE
STEREO
MONO
BRIDGED
1V
LEVEL
.2V
3V
+ BRIDGED --
SPEAKER
LEFTRIGHT
+-- --+
Be sure speakers are
connected with correct
polarity as shown.
+
Wall speakers,
shelf speakers, etc.
LeftRight
+
FIGURE 5 - PA635X STEREO MODE CONNECTIONS
When making connections to the PA635X be sure the power cord is unplugged. Proceed as follows:
Stereo Mode Connections
1. Using good quality RCA-type patch cables connect the L and R OUTPUT jacks of the driving preamp to the LEFT
and RIGHT input jacks on the PA635X. Do this for each amplifier pair. Refer to Fig. 5.
3. Using good quality speaker wire, connect the individual speaker leads to the 4-terminal "SPEAKER" connectors
on the PA635X as shown.
4. The PA635X is 4-Ohm safe in Stereo Mode. Make sure the impedance presented to the speaker terminals by the
speakers (or any combination of speakers) is 4-Ohms minimum.
5. Be sure to observe correct polarity by connecting the "+" and "–" terminal from each channel on the PA635X to
the corresponding "+" and "–" terminals on each speaker. This will ensure correct "phasing" - see Fig. 5 and
Speaker Phasing below. Since the connectors are removable, you may unplug them for ease of lead assembly.
6. As a rule of thumb, use 18 gauge speaker wire for speaker runs up to 30' (9m), 16 gauge up to 70' (21m), and 14
gauge up to 150' (39m). The 4-terminal connectors accept wire sizes up to 12-gauge max.
7. Strip the insulation back about 1/4" (6mm) and twist the strands on each lead to prevent fraying.
CAUTION: After lead ends are inserted and the screws tightened down, be sure there are no free strands that
could cause shorting!
Speaker Phasing
To obtain stable imaging and full bass response, it is imperative that stereo speakers be connected "in phase" with
each other. You can verify this as follows:
a) If the "+" (positive) and "–" (negative) terminals on your speakers are correctly marked, and visible, and you have
wired the system as shown in Figs. 5 and 6, then the system will be "in phase". No further action is required.
Most manufacturers identify the positive terminal with a red binding post, a "+" sign, or a red dot.
b) If you are unsure of the markings, you can verify the phasing. Using a mono sound source, such as AM radio,
alternately reverse the leads to one of the speakers. Pick the connection that delivers a solid center image
between the speakers as well as best bass response.
In general, it is recommended that the BRIDGED mode not be used
in multi-room applications where several
speakers are driven through room volume controls and the like.
For such applications, use the STEREO mode. Use the BRIDGED mode for single speaker, higher power
applications, such as in surround sound systems. Use speakers with an impedance rating of 8-Ohms minimum.
To make connections for the BRIDGED mode, follow the steps given before for stereo connections, but with the
following differences:
1. You may connect the RCA-type patch cables from the OUTPUT jacks of the driving preamp or other source to
either the LEFT or the RIGHT input jacks of the bridged pair, as shown in Fig. 6. Do this for just the amplifier pairs
you wish to run in the bridged mode.
CAUTION: Be sure Power is OFF when connecting or switching the amp into or out of BRIDGED operation.
2. Slide the MODE switch to the BRIDGED position.
NOTE: Do this only on the amplifier pairs you wish to run in the bridged mode!
3. Connect one speaker wire pair between the 4-terminal "SPEAKER" connectors on the PA635X and the speakers
as shown in Fig. 6. Be sure to use only the two outer terminals marked "+” and "–" on the 4-terminal connector as
shown on the panel for BRIDGED connections.
NOTE: Only one speaker is connected per amplifier pair in the BRIDGED mode!
CAUTION: W hen operating in the BRIDGED mode (particularly when bench testing the amplifier) do not make a
ground or any other kind of connection to the amplifier speaker terminals other than those to the individual
speakers as shown. Failures caused by inappropriate connections are not covered under the warranty.
Connecting the REMOTE MASTER ON/OFF CONTROL Terminal
As mentioned under "PA635X PANEL AND FEATURE DESCRIPTIONS", the REMOTE MASTER ON/OFF
CONTROL terminal allows the power to the PA635X to be turned ON and OFF by a remotely applied DC Voltage.
Fig. 7 illustrates how a PA635X can be switched ON and OFF via the switched AC outlet on the rear of a preamplifier.
When the preamplifier Power Switch is switched ON, power is applied to the DC adapter, which in turn applies 5V to
30V DC to the PA635X, switching it ON. Similarly, when the preamplifier is switched OFF, the DC voltage to the
PA635X is removed, turning it OFF.
This must be the positive (+)
lead (white striped lead on
Xantech Power Supply Adapters)
PA635X
(portion of rear panel)
Preamplifier, Control Center, etc.
FIGURE 7 - USING THE PA635X REMOTE MASTER ON/OFF CONTROL TERMINALS
Fig. 8, following, shows the PA635X in a typical multi-room system with a Xantech ZPR68-10 six-zone preamp. In
this case, the common +12V CO (control output) from the ZPR68-10 is used to remotely turn the PA635X ON/OFF.
When any one of the zones is turned on, the common +12V CO goes high, turning each of the PA635X's ON.
Similarly, when the last zone is turned OFF, the +12V CO drops to 0V and turns the PA635X's OFF.
ZPR68-10 Power
Supply
XANTECH
S-62/64/66
Wall Speakers
L
Smart
Pad
2
ZONE 1
RF Signal
IR Signal
ZPR68-10
SIX ZONE EIGHT SOURCE REMOTE PREAMP
COMMON IR LEVEL
12345678
HI
LO
1 2 3 4 5 6 7 8
IR CONFIRM
12345678
VIDEO
COM
PORT
L
AUDIO
POWER
R
CO
G
POWER
SUPPLY
Plug SAT Rec'rs into
nswitch
120 V AC (u
ed)
SAT Rec'r #1
V
LR
R
COMMON IR INDICATOR
COMMON IR OUTPUTS
SOURCE INPUTS
A/V
Patch Cords
AM/FM Tuner
LR
L
780-80
"J" Box
IR Receiver
ZONE 2
RF IN
TV
VIDEO IN
TV
L
Smart
Pad
2
R
CONSIDERATIONS"
4-Conductor
Home Runs.
CAUTION
See
"POWER SUPPLY
in ZPR68-10
Manual, page 10.
ZONE 3
+12V
GND
STATUS
IR IN
123456
VIDEO
L
AUDIO
R
2-Conductor
Mini-Plug-
to-Stripped
Ends. Use
6015900.
Remote
ON/OFF
ZONE CONTROL - IR INPUTS
ZONE IR OUTPUTS
ZONE OUTPUTS
SYLMAR, CA MADE IN U.S.A.
®
R
480-00
Dinky Link
IR Receiver
A/V
Patch Cords
Base
Band
Video.
Use
RG-6
Coax
Amp
RF
ANT. or
Cable
RF (TV)
Signal.
Use
RG-6
Coax
Combiner
Modulator
(2-Input)
To Zone IR Out 1,
ZPR68-10
SAT Rec'r #2
V
LR
To Zone IR Out 2,
ZPR68-10
V
VCR #1
To Zone IR Out 3,
ZPR68-10
VCR #2
To Zone IR Out 4,
ZPR68-10
LR
V
LR
Common IR Out 4,
SOURCE COMPONENTS
FIGURE 8 A Multi-Zone System Diagram Using The PA635X
: TO REDUCE THE RISK OF
FIRE OR ELECTRICAL SHOCK, DO NOT
EXPOSE THIS UNIT TO RAIN, MOISTURE
OR PLACE WATER FILLED OBJECTS ON
THE PRODUCT.
ATTENTION
: RISQUE DE CHOC ELECTRIQUE
NE PAS OUVRIR.
NO USER SERVICABLE PARTS INSIDE.
REFER TO OWNERS MANUAL FOR SAFETY INSTRUCTIONS.
ATTENTION
: POUR UN REGLAGE
CORRECT, SE REPORTER AU MANUEL
DINSTRUCTIONS.
MODEL PA635X
THIS DEVICE COMPLIES WITH
REMOTE
PART 15 OF THE FCC RULES.
MASTER
OPERATION IS SUBJECT TO
ON/OFF
THE FOLLOWING TWO
CONTROL
CONDITIONS: (1) THIS DEVICE
MAY NOT CAUSE HARMFUL
5-30 VOLTS DC
INTERFERENCE, AND (2) THIS
DEVICE MUST ACCEPT ANY
INTERFERENCE RECEIVED,
INCLUDING INTERFERENCE
THAT MAY CAUSE
UNDESIRED OPERATION.
+--
GROUND
LEFT RIGHT
LEVEL
LEFT RIGHT
ZONE 1
ZONE AMPLIFIER - MODEL
1
MODE
STEREO
MONO
BRIDGED
1V
.2V
3V
SPEAKER
USE CLASS 2
WIRING FOR
+-- --+
LOUDSPEAKERS
To Speakers in Rooms
WARNING
LEFT RIGHT
2
1V
LEVEL
.2V
3V
+ BRIDGED -- + BRIDGED --
SPEAKER
LEFT RIGHT
+-- --+
ZONE 2ZONE 3
LEFT RIGHT
TURN POWER
MODE
OFF BEFORE
CHANGING
STEREO
MODES
MONO
BRIDGED
LEVEL
3V
+ BRIDGED --
SPEAKER
LEFT RIGHT
PA635X
FUSE
6.25 AMP
3
SLOW BLOW
MODE
STEREO
MONO
BRIDGED
AC 120V 60Hz
5.5A 660 WATTS
1V
CAUTION
NEUTRAL
FUSING
.2V
AC LINE
+-- --+
ON/OFF
Page 10 Model PA635X
TROUBLE SHOOTING
If you encounter a problem, please review the items in the following list. Be sure, in addition, to check other system
components, such as preamplifiers, CD players, speakers, speaker wiring, etc., that may be at fault.
PROBLEM PROBABLE CAUSE AND SOLUTION
Rear panel Power Indicator does not light – no sound. Check line cord for good contact in a live AC outlet. If
REMOTE ON/OFF jack is used, be sure applied
voltage is between +5V and +30V DC with proper
polarity. See Fig. 7.
No sound from CH2, CH4 or CH6 when stereo
operation is desired.
BRIDGED/STEREO switch is incorrectly set to
BRIDGED position. Set to STEREO position. See
Fig. 6.
Sound cuts in and out every 3 to 5 seconds. Speaker load impedance is less than 4-Ohms for
Stereo mode or less than 8-Ohms for Bridged mode.
Make changes in speakers as necessary to obtain
higher impedance.
PA635X does not turn OFF when REMOTE input
voltage goes to 0 Volts.
PA635X becomes very warm, shuts OFF, but does not
come back ON automatically.
Be sure that the POWER switch (item 3, Fig. 2) is set
to the MANUAL OFF (REMOTE ON/OFF) position.
Set POWER switch (item 3, Fig. 2) to MANUAL OFF
(OUT) position for 15 seconds, then back ON. If
REMOTE ON/OFF jack is used, unplug for 15 seconds,
then re-plug.
One or more front panel LED’s glow red. The amplifier has been driven into clipping and/or is