QSC Audio PL224A User Manual

POWERLIGHT 2A

User Manual
Manuel de l’utilisateur
Bedienhandbuch
Manual del Usario

*TD-000089-00*

TD-000089-00

rev.A

PL2A Audio Power Amplifiers
with Analog Signal Processing

• PL218A

• PL224A

• PL230A

• PL236A

EXPLANATION OF GRAPHICAL SYMBOLS

The lightning flash with arrowhead symbol within an equilateral triangle is intended to alert the user to the presence of uninsulated “dangerous” voltage within the
product’s enclosure that may be of sufficient magnitude to constitute a risk of electric shock to humans.

The exclamation point within an equilateral triangle is intended to alert the user to the presence of important operating and maintenance (servicing) instructions in the
literature accompanying the product.

CAUTION

RISK OF ELECTRIC SHOCK

DO NOT OPEN

CAUTION: To reduce the risk of electric shock, do not remove the cover. No user-serviceable parts inside.
Refer servicing to qualified personnel.
WARNING: To prevent fire or electric shock, do not expose this equipment to rain or moisture.

FCC INTERFERENCE STATEMENT

NOTE: This equipment has been tested and found to comply with the limits for a class B digital device, pursuant to part 15 of the FCC rules. These limits are designed to provide
reasonable protection against harmful interference in a residential installation. This equipment generates, uses, and can radiate radio frequency energy and if not installed and used in
accordance to the instructions , may cause harmful interference to radio communications. However, there is no guarantee that interference will not occur in a particular installation. If
this equipment does cause harmful interference to radio or television reception, which can be determined by switching the equipment off & on, the user is encouraged to try to correct
the interference by one or more of the following measures:

- Reorient or relocate the receiving antenna.

- Increase the separation between the equipment and the receiver.

- Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.

- Consult the dealer or an experienced radio or TV technician for help.

© Copyright 2000, QSC Audio Products, Inc.

QSC® is a registered trademark of QSC Audio Products, Inc.

PowerWave™ is a trademark of QSC Audio Products, Inc.

“QSC” and the QSC logo are registered with the U.S. Patent and Trademark Office

All trademarks are the property of their respective owners.

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TABLE OF CONTENTS

Explanation of Graphical Symbols.......................................................2

FCC Interference Statement....................................................................2

INTRODUCTION:

PL2A Series Overview.................................................4

Front Panel...................................................................4

Rear Panel....................................................................5

Side Panel....................................................................5

FEATURES & SETUP:

Rear Panel Switches-

INPUT CONFIGURATION..............................................6

MODE...........................................................................7

DATAPORT INPUT SIGNAL..........................................8

GAIN-SENSITIVITY SELECT.........................................9

Side Panel Switches and SIP networks-

Subaudio Filter & Subaudio Frequency....................10

Lo Frequency Delay and HF ATTEN..................................11

HORN BOOST.............................................................12

POWER LIMITER........................................................13

CLIP LIMITER..............................................................15

Crossover & Delay SIP Networks.............................16

CONNECTIONS:

Inputs................................................................................21

Outputs............................................................................22

SECURITY PANEL USE & INSTALLATION...................................................24

OPERATION:

Gain Controls................................................................25

AC Power Switch...............................................................25

Front Panel LED Indicators.................................................25

Normal operating levels......................................................25

TROUBLESHOOTING.......................................................................................26

TECHNICAL OVERVIEW & BLOCK DIAGRAM............................................28

SPECIFICATIONS..............................................................................................30

WARRANTY INFORMATION..........................................................................32

HOW TO CONTACT QSC AUDIO PRODUCTS..............................................32

BLANK SETUP SHEETS...................................................................................33

DataPort, Front Panel LEDs, Gain Controls-

INSTALLATION:

Basic Overview...........................................................18

Rack mounting & Mounting Dimensions.................19

Fan Cooling & AC Mains..........................................20

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INTRODUCTION: PL2A OVERVIEW

Thank you for the purchase of your new POWERLIGHT 2A amplifier. To get the most
out of your amplifier, review this manual carefully. The installation and operation
sections provide proper connection and operation guidelines.

The POWERLIGHT 2A expands upon the features of the POWERLIGHT 2. The
flexibility, user-friendliness and reliability of this amplifier will make it a valuable
part of your system for years to come.

The POWERLIGHT 2A was designed to fit your system. You can adjust the input
sensitivity to match the output capability of your mixing board. DataPort input
signals can be summed before or after internal processing so that conflicts with
external processing are avoided. The 4th order Linkwitz-Riley crossover has
independent adjustment of crossover frequency and defeatable low-pass delay
time. The high-pass side of the crossover includes separate binary adjustments for
trim and driver EQ. The precision limiters provide separate adjustment of limiter
threshold, peak mode and attack/release times. You can adjust the limiter
threshold between 100% and 3% of available power. The limiters have a gentle
limiting knee which preserves a sense of signal dynamics. In bi-amplified systems,
a slower attack/release time can be used on the low frequency channel. The
limiters can also be connected together to maintain stereo balance in full range
mode or frequency balance in bi-amplified mode. A peak limiting mode with a fast
attack time provides protection for fragile high frequency drivers.

The POWERLIGHT 2A is easy to use. All operating mode switches are grouped
together on the rear panel. These critical switches have color-coded LED’s to
positively confirm switch position. A brilliant blue LED on the front clearly
indicates when the amplifier is in bi-amp mode. Limiter threshold, high-pass trim
(HF ATTEN) and high-pass EQ (HORN BOOST) levels use combinations of two
position switches for easy adjustment. These less used switches are located on
the side panel.

The POWERLIGHT 2A is built for the long haul. Rubber-isolated XLR input
connectors reduce stress on the contact pins and provide a tight, noise-free
connection. All signal processing is done in side loops and then returned to the
main signal path. This maintains high signal fidelity and provides a more robust
system in the unlikely event a processor ceases to function.

Your new POWERLIGHT 2A amplifier will give you many years of great sound. The
POWERLIGHT 2A is the most flexible, durable and best performing amplifier you
can buy.

FRONT PANEL

1. Power switch

2. Cooling vents

3. Gain control (1 per
channel)

4. CLIP, -10 dB, -20 dB and
SIGNAL indicator LEDs, 1
per channel

5. POWER, BRIDGE, and

PARALLEL indicator LEDs

6. BI-AMP indicator LED

7. Handles

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INTRODUCTION: PL2A OVERVIEW

REAR PANEL

1. DataPort

2. Terminal block inputs

3. Configuration switches

4. XLR inputs

5. Speakon outputs

6. Binding post outputs

7. Cooling air inlet vents

8. Serial number label

9. IEC connector for AC power cord
9a. Power cord retaining clip (install on item 8)

SIDE PANEL

1. Low pass delay network SIP* socket (J5)

2. Crossover frequency network SIP socket (J4)

3. Subaudio filter push-button switches (1 per
channel)

4. Subaudio filter “on” indicator LEDs (1 per channel)

5. DIP** switch for subaudio filter frequency select,
low frequency delay enable, HF attenuation
and horn boost

6. DIP switches for power limiting adjustments
and clip limiting enable

7. Activity LEDs for indication of power limiter
activity (1 per channel)

*SIP is the abbreviation for Single-In-line Package
**DIP is the abbreviation for Dual-In-line Package

Side cover plate removed for this illustration

5

FEATURES & SETUP- REAR PANEL SWITCHES: INPUT CONFIGURATION

INPUT CONFIGURATION- This switch selects between STEREO or PARALLEL

input configuration. The indicator LED’s above the switch confirm the switch setting.

STEREO: Each input is sent to its respective channel. Each channel has
independent subaudio filtering, clip limiting, gain control, and outputs. In

STEREO mode, a full-frequency signal may be presented to each channel.
When to use STEREO input configuration: Use STEREO for stereo

sources (L-R inputs) and any other situation that requires each channel to
be completely separate from the other.

PARALLEL: The CH 1 and CH 2 inputs are connected together, applying a

single input signal

input jack will drive both channels. Each channel's subaudio filtering, clip
limiting, and gain control still function independently. Each channel feeds
its own speaker load.

to both channels of the amplifier. A signal into any

You can patch the input signal on to additional amplifiers (“daisy-chain”)
by using any of the remaining input jacks. This feature eliminates the
need for “Y” cables.

The orange PARALLEL LED on the front panel clearly indicates when the
amplifier in configured for PARALLEL input.

When to use PARALLEL input configuration: Use PARALLEL when
you need one signal to drive both channels.

NOTE: Ensure that the INPUT CONFIGURATION
switch is set to STEREO when feeding two
separate signals to the two channels.

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NOTE: The “normal” position of the MODE
switch is 2 CH when operating in STEREO or
PARALLEL input for the operating conditions
shown above. See the following section for
more information regarding the MODE switch.

FEATURES & SETUP- REAR PANEL SWITCHES: MODE

MODE-

The indicator LED’s above the switch confirm the selection.

This switch selects between BI-AMP, 2 CH, or BRIDGE modes of operation.

BI-AMP: This puts the amplifier into a “crossover” mode. CH 1 receives
the low frequencies and CH 2 is receives the high frequencies. The
crossover is a 4th order Linkwitz-Riley. The crossover frequency and low­frequency alignment delay are “programmed” with SIP (single in-line
package) resistor networks . These small plug-in networks are installed
from the side of the amplifier and plug into J4 and J5. WARNING: Do not
insert or remove networks with the power turned on. See the SIP Network
Selection and Installation section for more information. The HF ATTEN,
HORN BOOST, and SUBAUDIO FILTER controls are active in BI-AMP
mode. The blue BI-AMP LED on the front panel indicates when the amp
is in bi-amp mode.

When to use BI-AMP mode: Use BI-AMP when you need to split the
high frequency and low frequency signals to power separate driver types.

2 CH: This is the “normal” mode used for stereo and parallel input
configuration. Each channel carries full-frequency signals (no crossover)
and is independently controlled (gain, processing, output connection).

BRIDGE: This mode combines both output channels into one output. This
mode is for driving a single, high-powered load with twice the “normal”
voltage swing. This results in about 4 times the peak power and about
three times the sustained power of a single channel. This mode uses the
input, gain control, subaudio filter, and clip limiter of CH 1; CH 2's filter
and clip limiter have no effect. The yellow BRIDGE LED on the front panel
indicates when the amp is in BRIDGE mode.

When to use BRIDGE mode: Use BRIDGE mode when you need to
deliver the power of two channels to a single 8 or 4 ohm load, such as a
subwoofer. Do not use less than 4 ohm loads in BRIDGE mode.

BRIDGE MODE OUTPUT CONNECTION-

Note that speaker connection for bridge mono mode is different than other modes.
See section on Connections: Outputs for proper bridge mode output connections.

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FEATURES & SETUP- REAR PANEL SWITCHES: DATAPORT INPUT SIGNAL

DATAPORT INPUT SIGNAL- This switch selects the regular inputs or the

DataPort inputs, and allows the DataPort to enter before or after the analog
processing. WARNING: There is no DataPort “flag” for this setting, so the appropriate
setting must be confirmed manually.

OFF: If the DATAPORT CONNECTION is not being used, set to the OFF position. The
DataPort MONITOR SIGNALS and STANDBY are still active, but the DataPort input signals
will not reach the amplifier.

PRE PROC: This setting will insert the DATAPORT signals ahead of the amplifier’s signal
processor. If you are using external processing on the DATAPORT input signal, be aware that
additional internal processing will be added to the signal. This may cause unexpected overall
results.

POST PROC: This selection inserts the DATAPORT signals after the amplifier’s processor.

The subaudio filters and clip limiting remain functional,

bypassed. See the Block Diagram for more detailed signal flow information.

DATAPORT signal routing options using the

but all other processing is

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DATAPORT INPUT SIGNAL

switch

FEATURES & SETUP- REAR PANEL SWITCHES: GAIN-SENSITIVITY SELECT

GAIN-SENSITIVITY SELECT- This switch selects the gain structure of the amplifier. Each channel

runs through a gain buffer which allows all models to have either a uniform 1.2 Vrms input sensitivity or
a uniform 26 or 32 dB of voltage gain (all measured with the GAIN controls at maximum). The internal
signal leaving this stage is approximately +4 dB, leaving about 16 dB of headroom for the rest of the
signal processing. NOTE: The GAIN-SENSITIVITY SELECT setting does not effect DataPort gain in any
mode.

1.2 Vrms: This selection sets the input sensitivity to approximately 1.2 Vrms.

This is the input voltage required to drive the amplifier to rated output power
into an 8 ohm load.

26 dB: This selection sets the maximum voltage gain of the amplifier to
approximately 26 dB.

32 dB: This selection sets the maximum voltage gain of the amplifier to
approximately 32 dB

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FEATURES & SETUP- SIDE PANEL SWITCHES: SUBAUDIO FILTER and SUBAUDIO FREQUENCY

The side panel cover plate must be removed to access the side panel switches.

CH1 SUBAUDIO FILTER, CH2 SUBAUDIO FILTER-

to turn on or off the SUBAUDIO FILTER for each channel.

LED illuminates when the filter is ON. Push in and allow the switch to release for
LED extinguishes when the filter is OFF.

The filter’s roll-off frequency is determined by each channel’s SUBAUDIO FREQUENCY switch.
When the filter is switched OFF, a 5 hertz roll-off frequency protects the load against DC or deep
subaudio output from the amplifier.

use the

SUBAUDIO FILTER

frequencies below the speaker’s limits.

systems with rated frequency response below 30 hertz or if low frequency filtering is provided by
other devices.

Unless you already have filtering upstream of the amplifier,

to protect your speakers from cone over-excursion caused by

The OFF position should be used only for subwoofer

These push-button switches are used

Press the switch in for ON; the green

OFF

; the green

CH1 SUBAUDIO FREQUENCY, CH2 SUBAUDIO FREQUENCY- These switches

determine the low frequency roll-off of the SUBAUDIO FILTER. Generally, match the frequency
selection to your speaker’s low frequency capability. This improves speaker performance by
limiting subaudio cone movement, making more power available for the speaker’s rated
frequency range. 30 Hz and 50 Hz are the available settings. If the SUBAUDIO FILTER switches
are OFF, these settings will have no effect. These switches are located on sections 1 and 10 of
the left-most DIP switch.

Subaudio filter frequency response- filter off

Subaudio filter frequency response- filter on, 50 hertz selected Subaudio filter frequency response- filter on, 30 hertz selected

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FEATURES & SETUP- SIDE PANEL SWITCHES: LO FREQ DELAY and HF ATTEN

LO FREQ DELAY-

switch controls an additional analog delay which adds to the inherent delay of the low
frequency filter. The amount of delay is determined by the SIP programming network installed
in the DELAY NETWORK socket (J5). DELAY OFF disables the delay. ENABLE LO FREQ
DELAY activates the delay. Refer to the SIP network value selection chart for more
information.

This switch is active only when the amplifier is in BI-AMP mode. This

HF ATTEN- These switches are active only when the amplifier is in BI-AMP mode.

These four switches (section 3, 4, 5, and 6 of the left-most DIP switch) work in
combination to control the amount of high-frequency attenuation. The amount of
attenuation can be selected in 1dB steps from 0 to 15 dB. Add the selected switch values
for the total attenuation. EXAMPLE: Setting -1 dB and -4 dB results in -5 dB of high
frequency attenuation.

Typical crossover frequency response curve showing

the range of adjustment of the

Crossover frequency is programmable.

HF ATTEN

switches.

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