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Amplifiers & Preamplifiers

In addition, this switch must be left in the MANUAL OFF (OUT) position to permit an external DC
Control Voltage to power the PA1235 ON and OFF.

Refer to "

REMOTE MASTER ON/OFF CONTROL

" terminals, item #13.

NOTE:

  The PA1235 may also be powered ON/OFF with an external AC line switch into which the

power cord of the PA1235 is plugged (such as the switched AC outlet of a preamp, timer, etc.).

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:

a) They show Power ON/OFF and Standby ON/OFF conditions.

b) They flash Amber 5 times during power up, then turn steady Green when Power On Mute releases.

On power down, they flash Amber once, then go off.

This action occurs  whether the unit is powered ON and OFF by the POWER switch (item # 3) or
by a DC voltage applied to the REMOTE MASTER ON/OFF CONTROL terminals (item #13).  Be
sure the rear panel master AC LINE ON/OFF Switch, item #17, is set to the ON (

I

) position for the

above to occur.

c) They will go Off when the Standby OFF IR command is received.  Sending a MUTE OFF command

will restore operation.  Also, LEDs blink with Volume action.

d) A Mute command will cause them to blink Green (Red if Volume is within 5 dB of Max-V).  Mute

is released when any other PA1235 command is sent.

e) Changing an IR Code Group will cause them to blink Amber, confirming the change has taken

effect.

f) When the volume level is increased to a range within 5 dB of MAX-V, the LED color changes from

Green to Red.   

NOTE:

  Red indicates that volume is approaching maximum ---

 not

 an indication

of power output level.

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. COMMON BUS / LOCAL 

Switch.  Switches the amplifier stereo pair inputs between the LOCAL

(LEFT/RIGHT) jacks, item #5 and the COMMON AUDIO BUS (LEFT/RIGHT) jacks, item #8.  In this
way, each amplifier pair can be driven by separate zones or sources or from a common source via the
COMMON AUDIO BUS.

7. MODE

 Switch. Switches the amplifier pair between 

STEREO

MONO

 and 

BRIDGED

 modes.

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.

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.

In 

BRIDGED

 mode, the two amplifiers are bridged for a single channel of high power output (150 Watts

@ 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 #12, following).

PA1235

Summary of Contents for PA1235

Page 1: ...arge single multiple filtered power supply delivers high quality at a reasonable price IR Controlled Volume Level Volume can be ramped from zero output to maximum for individual channel pairs or as gr...

Page 2: ...12 Volt common CO Control Output on the Xantech ZPR68 to power one or more PA1235 s ON and OFF automatically with first zone ON and last zone OFF commands Default settings As received from the factor...

Page 3: ...range within 5 dB of MAX V the LED color changes from Green to Red NOTE Red indicates that volume is approaching maximum not an indication of power output level 5 Line Inputs These RCA type jacks are...

Page 4: ...VDC output 9V 70 mA with ON condition 0 Volts output OFF Standby GROUND Ground for IR IN STATUS out CI in CI Control Input Use for control of Standby ON OFF of amplifier pairs if desired instead of b...

Page 5: ...l amplifier pairs item 11 except they apply to all amplifier pairs in common That is IR commands for Volume Mute etc control all amplifier pairs together NOTE Individual control of amplifier pairs is...

Page 6: ...en the CI terminal is driven high with an external control voltage Refer also to items 9 and 11 Fig 3 4 C BAL Command Instantly returns the balance to the Center position equal volume in each channel...

Page 7: ...s in the PA1235 are set to code group number A0 Be sure to set the RC68 to the same number It may be necessary to change the PA1235 amplifier pairs to different code groups if you wish to address each...

Page 8: ...nd 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 PA1235 When mak...

Page 9: ...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 T...

Page 10: ...control to the RS41AV and the Source Components and to power the keypads and IR receivers three leads are connected between the CB18 and a 789 44 Connecting Block 6 Since a common IR bus is used to k...

Page 11: ...R CA AC 120V 60 HZ 4 AMP LEVEL RESET RIGHT 0 9 8 6 7 4 5 2 3 1 GND 12V CB18 Parallel Connecting Block 780 80 J Box IR Receiver ROOM 2 R L ST G V IR ROOM 1 R L Smart Pad 3 ST G V IR IR CONFIRM V V POWE...

Page 12: ...ion in each room It also carries a COMMON IR signal to a 789 44 Connecting Block for control of the RS41AV Remote Switcher and the Source Components 2 Note that the ZONE numbers on the 796 20 do not a...

Page 13: ...EKEEP IR The PA1235 has been designed specifically to work well with both Zone and All Zone ON OFF management as rendered by the ZPR68 10 In this example the STATUS GND output 0 to 12 VDC of each zone...

Page 14: ...IN G 12 IN G 12 IN G ZONE 6 ZONE 5 ZONE 4 ZONE IR INPUTS 12 IN G 12 IN G 12 IN G A B A B A B ZONE 4 ZONE 5 ZONE 6 12 OUT G SYLMAR CA MADE IN U S A ZONE EMITTERS ZONE EMITTERS 796 20 SIX ZONE CONNECTI...

Page 15: ...does not turn OFF when REMOTE input voltage goes to 0 Volts Be sure that the POWER switch item 3 Fig 2 is set to the MANUAL OFF Out position 5 PA1235 becomes very warm shuts OFF but does not come bac...

Page 16: ...z to 55 kHz Input Sensitivity Rated Power stereo mode Input Gain IR Controlled Setting Max 0 5 V Default 1 0 V Min Off Input Impedance LOCAL Inputs 22 kOhms COMMON AUDIO BUS Inputs 70 kOhms Power Sour...

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