Xantech Stereo Amplifier PA435X User Manual

INSTALLATION INSTRUCTIONS

MODEL PA435X

FOUR CHANNEL POWER AMPLIFIER

TABLE OF CONTENTS

SectionTitle

Page

SAFETY INSTRUCTIONS - READ BEFORE OPERATING EQUIPMENT.........................................................................................................2

GENERAL INFORMATION .............................................................................................................................................................................3

PA435X PANEL AND FEATURE DESCRIPTIONS ..........................................................................................................................................5

INSTALLATION - PHYSICAL LOCATION AND MOUNTING ............................................................................................................................8

CONNECTING THE PA435X ..........................................................................................................................................................................9

Stereo Mode Connections...................................................................................................................................... 9

Speaker Phasing.................................................................................................................................................. 10

Mono Mode Connections...................................................................................................................................... 10

Bridged Mode Connections .................................................................................................................................. 11

Connecting the REMOTE MASTER ON/OFF MUTE CONTROL........................................................................... 12

A Multi-Zone System Diagram Using The PA435X and MRC88............................................................................ 13

TROUBLE SHOOTING .................................................................................................................................................................................15

SPECIFICATIONS........................................................................................................................................................................................16

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Model PA435X

Page 3

GENERAL INFORMATION

To enhance the ease of installation and obtain optimum performance from the PA435X, we recommend that you first

become familiar with all its features and special capabilities by studying the descriptions and instructions in this

manual.

The PA435X was designed to meet the audio power amplifier needs of custom installed multi-zoned systems with

high sonic quality. It is a 4 Channel amplifier that is primarily intended to interface with the MRC88 Whole-house

Audio Video Entertainment System for Zones 7 and 8 Preamp outputs or for Sub-Zone amplification of zones 1-6. It

may also be used as a standalone single or 2-zone amplifier. Specific features and technology are as follows:

Figure 1: The Model PA435X Amplifier

Cost/Size Efficiency. The PA435X features four 35-watt power amplifiers. This permits each PA435X to drive 2-

zones in a multi-zone system -- each with a 35-watt stereo amplifier per zone.

4-3-2 Output Flexibility. Either pair of amplifiers can be bridged to allow several channel and power output

capabilities. It can be configured into three power packages as follows:

•

Four 35-watt amplifiers. (4 Mono speaker outputs or 2 Stereo Zone outputs)

One 70 and two 35-watt amplifiers. (1 Mono 70 Watt and 1 Stereo 35-watt output)

Two 70-watt amplifiers (single Zone Stereo 70-watt output)

Remote ON/OFF Control Jacks (C1 & C2). These 3.5mm Stereo Mini Jacks allow the PA435X to be powered on

and off and muted by a positive DC voltage ranging between 4 and 30 volts (11mA @ 12 V). Specifically, when

interfaced with the Control Out jacks of zones 7 & 8 on the MRC88 (labeled CO1 and CO2), it permits the MRC88 to

power the PA435X ON and OFF automatically with zone ON/OFF commands.

Input Level Flexibility. The input levels are individually 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.). When set to the 1:30 position, this will match the sensitivity level of the standard

Amplifier output setting of the MRC88.

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.

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Page 4

Model PA435X

Peak/Clip LED Indication: Whenever either amplifier channel output starts to enter a clipping state, a front panel

LED will illuminate RED. After the amp stops clipping the LED will return to its normal state 5-6 seconds after clipping

stops.

Auto Protection Circuit. This feature protects the PA435X if a short or very low impedance is detected at the

speaker terminals with each amplifier pair protected separately. Normal operation is restored automatically within 3 to

4 seconds after the short is removed.

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Model PA435X

Page 5

PA435X PANEL AND FEATURE DESCRIPTIONS

1. Front Panel . 17" X 3.5” panel designed for shelf mounting. The unit measures 4” high with the Feet (Item #5).

When rack mounting use an adequate rack shelf mount making sure to allow for proper ventilation.

FIGURE 2 – THE MODEL PA435X FRONT PANEL – FEATURES AND FUNCTIONS

2. POWER/STANBY SWITCH:

POWER ON/OFF MODE: When the front switch is pressed to the IN position, the PA435X may be

controlledremotely from the MRC88 leaving the amplifier in STANDBY MODE when any of the Zones are

powered OFF via the CI1 and CI2 Control Inputs.

STANDBY MODE: When the front switch is the OUT position the amplifier may be totally

controlled via the MRC88; turning the amp ON when either Zone of the MRC88 is powered up and

powering the amp OFF when both Zones are OFF via the CI1 and CI2 Control Inputs.

NOTE: The rear power switch (Item #15) needs to be in the ON (I) position for both modes of operation

3. Status LED Indicators . These indicators, one for each channel pair, provide the following status information:

GREEN LED: Indicates Amplifier is ON

RED LED: Indicates associated channel output is in a CLIPPING state. LED will go back to GREEN 5-6

seconds after clipping subsides.

ALL LED’s OFF: Indicates both amplifier channels are OFF or in STANBY MODE (see Item #4 for

STANDBY MODE)

4. Illuminated LOGO: This is a backlit logo. When lit it indicates that the amplifier is powered ON. If the

individual STATUS LED’s (Item #3) are OFF but the LOGO is ON. This indicates that both amplifier channels

are currently in STANDBY MODE. Whenever the LOGO is not illuminated, this indicates the amplifier is

powered OFF.

5. Feet: Provides required ½” spacing when unit is shelf mounted to allow for proper ventilation. These feet

should not be removed. (see the section entitled MOUNTING for further information)

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Page 6

Model PA435X

FIGURE 3 – PA435X REAR PANEL - FEATURES AND FUNCTIONS

6. Line Inputs. These RCA-type jacks are the audio inputs for each of the amplifier pairs. Connect them to

the Preamp Output jacks of Zone 7 & 8 of the MRC88 (or other driving preamp output) with good quality

RCA-type patch cables. Note that the inputs are marked LEFT-A-RIGHT, LEFT-B-RIGHT signifying the

stereo channel pairs. Both the LEFT and RIGHT jacks are always active even when the MODE switch

(item #8) is set to the MONO or BRIDGED mode.

7. 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 maximum volume, 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

unwanted power levels.

NOTE: To set the Input Level Control for matched output to the MRC88 Speaker output, set the Input

Level Control on both pairs to the .7v (1:30) position as shown in Figure 4 below.

Matched MRC88 Setting

(0.7v = 1:30 position)

Figure 4: PA435X Level Adjustment setting when used with MRC88

8. 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.

b. In MONO mode, left and right input signals are summed internally for Mono output from each of the

two amplifiers. When interfacing a mono audio source, either the Left or Right (item #6) inputs may

be used.

c. In BRIDGED mode, the two amplifiers are bridged for a single channel of high power output (70

Watts @ 8 Ohms). Either the Left or Right input (item #6) may be used to drive the resultant single

channel amplifier.

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Model PA435X

Page 7

CAUTION: Be sure to have the rear AC LINE POWER switch (Item #15) turned OFF (O) when

changing the position of this switch and when making the corresponding speaker connection

changes.

9. 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.

NOTE: Replacement with a fuse of higher rating will not protect the amplifier and will void the warranty.

10. 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.

11. 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.

12. REMOTE MASTER ON/OFF and MUTE CONTROL (CI1 & CI2). These two Stereo Mini Jack

connections allow each individual channel pair of the PA435X to be powered ON and OFF and muted by

a control voltage ranging between 5 and 30 Volts DC (16mA @ 12 V). When connected to the C01 and

C02 jacks from Zones 7 & 8 on the Xantech MRC88, this will allow remote Power ON/OFF control directly

from the MRC88 System Controller. This allows the ‘A’ & ’B’ amplifier channel pairs to be individually

controlled by Zone 7 & 8 of the MRC88. (Tip = ON/OFF Standby Control; Ring = Mute Control; Sleeve =

gnd).

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.

13. 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).

14. Rear Panel ON/OFF LED. This LED indicates the power ON/OFF condition of the entire PA435X,

whether activated by a REMOTE MASTER ON/OFF CONTROL (item #11) or from the rear panel AC

Line Power switch (item # 15).

15. Master AC LINE ON/OFF Switch. Turns power OFF to the entire PA435X, regardless of front panel

POWER switch conditions. Must be placed in the ON (I) position for the other power switching functions

to work.

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Page 8

Model PA435X

INSTALLATION - PHYSICAL LOCATION AND MOUNTING

Upper shelf, component, wall, etc.

2-inch spacing

(minimum)

Keep perforations on top cover free of

PA435X

obstructions for max. cooling effect.

Convection

Airflow

To maximize air flow, route

single large opening in lower shelf.

Keep perforations on bottom

plate free of obstructions.

Figure 5 – HORIZONTAL MOUNTING

When you mount the PA435X, 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, you will have to pay even closer attention to adequate

ventilation.

4. Do not hesitate to use fans (quiet, boxer type), if necessary, to ensure a constant flow of air through the PA435X'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 PA435X 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 strain relief for the leads and dress them in such a manner so as

not to block airflow.

7. The PA435X is designed for shelf mounting on flat horizontal surfaces. When mounting into a 19" rack, use an

appropriate rack kit.

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Model PA435X

Page 9

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 PA435X

MRC88 Preamp Ouptus

or Other

PREAMP OUT

STATUS

ZONE IR

Set MODE

Switch to

STEREO position

PA435X

Rear Panel

RCA Type

Patch Cords

LEFT

RIGHT

MODE

STEREO

MONO

BRIDGED

LEVEL

.2V

BRIDGED --

SPEAKER

LEFT

-- -^R- ^IGHT

Be sure speakers are

connected with correct

polarity as shown.

–

Wall speakers,

shelf speakers, etc.

Left

Right

Figure 6 - PA435X Stereo Mode Connections

When making connections to the PA435X 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 MRC88 Pre Amp Output or

other driving preamp to the LEFT and RIGHT input jacks on the PA435X. Do this for each amplifier pair. Refer to

Fig. 6.

2. Slide the MODE switch to the STEREO position.

3. Using good quality speaker wire, connect the individual speaker leads to the 4-terminal "SPEAKER" connectors

on the PA435X as shown.

4. The PA435X 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.

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Page 10

Model PA435X

5. Be sure to observe correct polarity by connecting the "+" and "–" terminal from each channel on the PA435X to

the corresponding "+" and "–" terminals on each speaker. This will ensure correct "phasing" - see Fig. 6 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.

Mono Mode Connections

1. Using good quality RCA-type patch cables connect mono output jack of the driving preamp to the LEFT or RIGHT

input jack on the desired channel of the PA435X. Both the LEFT and RIGHT input jacks of the PA435X are active

in Mono Mode. If both jacks are utilized simultaneously, the signals placed on the input terminals are ‘summed’

together.

2. Slide the MODE switch to the MONO position.

3. Using good quality speaker wire, connect the individual speaker leads to the 4-terminal "SPEAKER" connectors

on the PA435. Both the LEFT and RIGHT Speaker outputs will be active with the identical program output

4. The PA435X is 4-Ohm safe in Mono Mode. Make sure the impedance presented to the speaker terminals by the