2
GENERAL INFORMATION
To enhance the ease of installation and obtain optimum performance from the PA640, we recommend that
you first become familiar with all its features and special capabilities by studying the descriptions and
INPUT PANEL
POWER
REMOTE
ON/OFF
C H 1 C H 2
BRIDGED
STEREO
LEVEL
LEVEL
LINE INPUTS
LINE INPUTS
BRIDGED
STEREO
C H 3 C H 4
LEVEL
C H 5 C H 6
LINE INPUTS
BRIDGED
STEREO
1V
.2V
3V
1V
.2V
3V
1V
.2V
3V
SYLMAR, CA MADE IN U.S.A.
PA640
SIX CHANNEL POWER AMPLIFIER
®
Fig. 1 The Model PA640
instructions in this manual.
The PA640 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 multichannel 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 PA640 features six 40-watt power amplifiers. This permits each PA640 to
drive 3-zones in a multi-zone system -- each with a 40-watt stereo amplifier per zone. The low profile
design, plus multiple amplifiers in a single package, delivers high quality at a reasonable price.
• Input Level Flexibility. The input levels are individually adjustable (per stereo pair) from a low of 0.2 volts
up to 3.3 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.).
• 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:
- Six 40-watt amplifiers.
- One 140 and four 40-watt amplifiers.
- Two 140 and two 40-watt amplifiers.
- Three 140-watt amplifiers.
This gives the PA640 added use in many other applications, such as driving surround sound speaker
systems.
• Low Impedance Capability. Each amplifier is 2-Ohm safe under music conditions in stereo mode and
4-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.
• Discrete Output Devices. All output and driver transistors are separate devices connected in a full-
complimentary Darlington configuration. This provides highest reliability in concert with highly linear
dynamic performance free of T.I.M. and slew induced distortions.
• Auto Protection Circuit. Protects the PA640 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 ON/OFF Jack. This jack allows the PA640 to be powered on and off by a positive DC voltage
ranging between 4 and 30 volts (11 mA @ 12 V). Specifically, it permits the 12 volt CO (Control Output)
from the Xantech ZPR68 to power one or more PA640's on and off automatically with zone ON/OFF
commands.
PA640
