RDL FP-PA18 Datasheet

FLAT-PAK™ SERIES

Model FP-PA18

18 W Audio Power Amplifier with Power Supply

 18 Watts RMS into 8 
 Automatic Energy-Saving Sleep Mode
 Selectable Sleep Delay: Off, 5, 15, 25 Minutes
 Input / Output Detachable Terminal Block Connections
 Line Level Balanced or Unbalanced Input
 Compressor/Limiter Controls Clipping
 LED to Indicate Audio Compression Threshold


Compressor Produces Maximized Average Output Power

 Audio Quality Superior to Standard Amplifiers
 Ultra-compact All Metal Construction
 High-Efficiency Class D Operation
 Thermal and Short-Circuit Protection

The FP-PA18 is part of the group of versatile FLAT-PAK products from Radio Design Labs. The unique FLAT-PAK case can be directly screwed
or bolted to cabinets or shelves. Optionally available rack-mounting accessories permit single or multiple FLAT-PAK module mounting.

APPLICATION:

compressor and an automatic sleep mode. The FP-PA18 features a balanced line level input that may be connected unbalanced.
A gain control located next to the terminal block is designed to be adjusted manually or with a trimming screwdriver. The gain
range will accommodate standard unbalanced levels as well as professional balanced levels. The output drives one 8 ohm
speaker or multiple speakers connected to present an 8 ohm load to the amplifier.

The FP-PA18 includes an analog compressor/limiter for fidelity audibly superior to conventional class D amplifiers with digital
limiting. The input GAIN setting determines whether the limiter alone is used for clipping suppression, or if the full
compressor/limiter will be used to substantially increase the average output power beyond that of a standard 18 W amplifier. A red
COMPRESSION LED flashes when the limiter is preventing output clipping. Normal audio level signals remain unaffected by the
compressor thereby preserving audio dynamics. If the input level is increased so that the compressor is active, the LED remains
dimly lit between peak flashes. The audio is compressed according to three dynamic time constants providing aural transparency
while maintaining clean, unclipped amplified audio for input overloads of up to 20 dB. The FP-PA18, with compression, is capable
of producing average audio output levels and clarity normally expected from amplifiers with a much higher output power rating.

The FP-PA18 circuits are all designed for low power consumption. In the absence of an audio input, a digital timer is enabled to
switch the class D output stage off. When this sleep mode is active, the amplifier module and its included RDL power supply
consume less than 1 W of mains power. A control on the end plate sets the sleep mode delay timer to 5, 15 or 25 minutes. The
control also permits the installer to bypass the sleep mode to conform to system specifications that require the amplifier to be
active at all times. Upon detection of an input signal, the amplifier is nearly inaudibly and instantly restored to full operation within
150 milliseconds.

The output stage includes an audio detector that illuminates the green OUTPUT ACTIVE LED and provides an active open
collector output when amplified audio is present at the module output. This output is useful to control other equipment or to verify
amplifier operation using high or low frequency low-level test tones. The detector triggers with only 30 mW of output power at
20

Hz or 5 mW of output power at 20 kHz.

A blue POWER LED illuminates when the FP-PA18 is powered from its external 24 Vdc power supply. The power LED is dimly
illuminated when the sleep mode disables the amplifier and glows brightly when the amplifier operation is fully enabled. The
module is equipped with both thermal and output short-circuit protection. The high-efficiency Class D output stage produces
minimal heat for all levels of expected voice or music modulation.

Wherever an ultra-compact, high quality, high efficiency eco-friendly audio power amplifier is needed to provide reliability and
unsurpassed versatility, the FP-PA18 is the ideal choice. Use the FP-PA18 individually, or combine it with other RDL products as
part of a complete audio/video system.

The FP-PA18 is a high efficiency 18 W power amplifier with a line input, 8 ohm output, integral audio

RDL  659 6th St.  Prescott, AZ., USA 86301  [phone]  FAX [phone]  www.rdlnet.com

FLAT-PAK

Model FP-PA18

18 W Audio Power Amplifier with Power Supply

Mounting
The FP-PA18 should be mounted in a location with good ventilation. If the module is mounted using a box
that does not provide ventilation, the amplifier should be secured to the outside surface of the box. The ambient operating environment must not exceed 40 degrees C.

™

SERIES

Installation/Operation

Declaration of Conformity available from rdlnet.com.

Sole EMC specifications provided on product package.

Specifications are subject to change without notice.

UNBALANCED

LINE-LEVEL

+

-

BALANCED

LINE-LEVEL

8 OHM SPEAKER

END

VIEW

THE O/C TERMINAL IS PULLED TO
GROUND WHEN AN AUDIO SIGNAL IS
PRESENT AT THE AMPLIFIER OUTPUT.
CONNECT THE TERMINAL TO AN
INDICATOR OR TO THE LOGIC INPUT OF
OTHER EQUIPMENT (GROUND TERMINALS
MUST BE CONNECTED BETWEEN THE
OTHER EQUIPMENT AND THE MODULE).

THE O/C TERMINAL MAY BE USED TO

VERIFY THE OPERATION OF THE FP-PA18
OR TO SWITCH ON OTHER EQUIPMENT
BASED ON PRESENCE OF AUDIO SIGNAL.

TYPICAL PERFORMANCE

Inp ut: Line level (+4 dBu nominal balanced;

-10 dBV nominal unbalanced)
Input Impedance: 10 k balanced bridging; 5 k unbalanced
Gain Adjustment: Single turn audio taper
Minimum Input Levels:
Balanced: ………………-18 dBu (to cross compressor threshold)

Unbalanced: ………......-20 dBV (to cross compressor threshold)

Maximum Input Levels:

Balanced: …………......+23 dBu

Unbalanced: …………..+21 dBV
Frequency Response: 20 Hz to 20 kHz (+/- 1 dB)*
THD+N: < 0.5% (20 Hz to 20 kHz)*
Compressor: Threshold 3 dB below rated output, automatically adjusting attack and release times
Noise: < -72 dB (below 18 W RMS, +4 dBu input)
CMRR: > 45 dB (50 Hz to 3 kHz)
Output Power: 18 W RMS into 8 
Output Circuit: Class D
Output Signal Detector Threshold: 30 mW @ 20 Hz; 20 mW @ 30 Hz; 10 mW @ 50 Hz;
5 mW @ 65 Hz through 20 kHz
Output Signal Detector Output: Open collector, 5 mA
Sleep Mode Power Consumption: < 1 W ( amplifier and included power supply)
Sleep Mode Delay: 5, 15 or 25 minutes (selectable)
Sleep Mode Disable: Selectable
Active Mode Delay: < 150 mS after input audio detected
Audio Detector Threshold: -50 dBu balanced, -52 dBV unbalanced
Ambient Operating Environment:
Indicators (3): Red LED: COMP LED indicates compressor activity

Green LED: OUTPUT ACTIVE (controlled by output signal detector)
Blue LED: POWER on; Dim: Sleep mode active; Bright: Amplifier active
24 Vdc power supply current: 16 mA (idle), 975 mA (max.), Ground-referenced
Power Supply (included): 100 to 240 Vac, 50-60 Hz, 1A max.; 24 Vdc output to module
Dimensions: Height: 1.15 in.(2.92 cm); Widt h: 3.25 in.(8.26 cm); Length: 3 in.(7.62 cm)

*measured at compressor threshold level equaling 12 W RMS output power

891-2155A

0° C to 50° C Maximum

Europe [NH Amsterdam] (++31) 20-6238 983; Fax: (++31) 20-6225-287

ADJUST AMPLIFIER GAIN

GAIN

COMPRESSION LED INDICATES
COMPRESSOR ACTIVITY. ADJUST SO
LED DOES NOT FLASH CONTINUOUSLY
FOR NORMAL LEVELS.

Sleep Mode is automatic after the sleep delay time has elapsed following absence of input audio.

Sleep Mode may be activated manually by repowering the module with input audio absent.

Radio Design Labs Technical Support Centers

U.S.A. [phone], [phone]; Fax: [phone]

+

AUDIO

-

INPUT

+

8 OUTPUT

Ω

-

+

POWER

OUTPUT PRESENT

O/C

PWR BRIGHT=ACTIVE MODE

18 WATTS RMS

PLUS COMPRESSION

DO NOT GROUND

OUTPUT TERMINALS

OR

OUTPUT PRESENTCOMPRESSION

24VDC 1A

VIEW

REGULATED

24 VDC POWER

SUPPLY ONLY

POWER INDICATOR
ILLUMINATED (BRIGHT OR DIM) = ON
BRIGHT = AMPLIFIER FULLY ACTIVE
DIM = AMPLIFIER SLEEP MODE

THE 'OUTPUT PRESENT' LED
INDICATES AUDIO IS PRESENT AT
THE AMPLIFIER OUTPUT AND THE
OPEN COLLECTOR (O/C) TERMINAL
IS PULLED TO GROUND.

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 Rule. These limits ar e designed to
provide reasonable protection against harmful interfer ence
in a residential installation. The equipment generates,
uses and can radiate radio frequency energy and, if not
installed and used in accordance with 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 televis ion reception,
which can be determined by turning the equipment off an
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 receiver

 Connect the equipment into an outlet on a circuit

different from that which the receiver is
connected.

 Consult the dealer or an experienced radio/TV

technician for help.

ADJUST THE CONTROL
WITHIN THE INDICATED AREA
FOR A SLEEP DELAY OF 5, 15
OR 25 MINUTES AFTER LAPSE
OF AUDIO. SET TO 'DISABLE'
TO FORCE AMPLIFIER TO

END

REMAIN FULLY ON. DO NOT
DISABLE FOR ENERGY
EFFICIENT INSTALLATIONS!

5

MINUTES

SLEEP DELAY

2515

DISABLE