RDL FPALC1 Quick Start Guide

™

FLAT-PAK

SERIES

Model FP-ALC1
Automatic Level Control

ANYWHERE YOU NEED...

•

Consistent Levels from Variable Sources

•

Split-Band AGC for Audio Transparency

•

Self-adjusting Attack and Release Times

•

AGC with Simple Single Control Setup

•

Level Control Range >20 dB

•

Gated Control to Avoid Level “Seeking”

•

Convenience of RDL FLAT-PAKs

You Need The FP-ALC1!

The FP-ALC1 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. All FLAT-PAK modules are supplied with a power interconnect cable for daisy-chaining
multiple modules from a single power supply.

APPLICATION:

professional sources with varying audio output levels. Power connections are made using either the full-size barrier block
terminals or a dc power jack located in one end panel. A second dc power jack is provided on the other end panel for
connecting additional FLAT-PAK modules.

The FP-ALC1 is a single channel (mono) module featuring detachable terminal block input and output. A single user
adjustment makes installation simple and efficient. The gain adjustment is set as high as possible with the loudest source
without the
audio source levels, such as multiple CD changers, satellite receivers or paging sources benefit from consistent levels.

The automatic level control circuitry in the FP-ALC1 maintains a consistent +4 dBu output for input signal variations as great
as 25-dB. Yet the operation of the module is nearly transparent to the listener for a wide variety of source material from rock
to classical. The level pumping effect frequently associated with automatic gain and compression devices is minimized in the
FP-ALC1 by controlling mid and high band audio separately from the bass frequencies. The automatic gain circuitry and
compression attack release times adjust according to the program material to further reduce any audible effects of the
module. The level seeking effect also associated with various automatic level products is avoided in the FP-ALC1. When
audio levels fall and remain below a level appropriate to that source, the module stops increasing the gain. As audio levels
fade out, the module tracks the level for a natural sound. These features combine to produce nearly inaudible adjustment yet
consistent levels without the listener fatigue associated heavily compressed music dynamics.

Common FP-ALC1 applications include paging outputs from telephone systems, music-on-hold feeds for telephone systems,
background or foreground amplifier inputs in sound systems, voice feeds in communications/intercom systems. When used
as a general level control in a paging system, the installer must use care in separating microphones from paging speakers to
avert potential feedback.

The FP-ALC1’s low profile and compact size permit mounting in confined spaces and in various locations in equipment
racks. The location of the input/output jacks permits high density mounting against flat surfaces while maintaining
accessibility to the connectors. The economical cost can provide assurance of correct signal levels in nearly any stereo audio
system. The FP-ALC1 may be mounted where needed, to rack sides or in an equipment rack (either the front or rear rack
rails) using the RDL FP-RRA. Use the FP-ALC1 individually, or combine it with other RDL products as part of a complete
audio/video system.

The FP-ALC1 is the ideal choice in many applications where consistent audio levels are needed from

INPUT OVERLOAD

indicator flashing. No further adjustments are needed. Sound systems fed from variable

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

™

FLAT-PAK

SERIES

Model FP-ALC1
Automatic Level Control

2A MAX

BUS

GAIN

INPUT OVERLOAD

+

OR

24 VDC

POWER

SOURCE

24 VDC

POWER

1A MAX

INPUT

AUDIO INPUT

AUDIO OUTPUT

BALANCED +4 dBu

Installation/Operation

EN55103-1 E1-E5; EN55103-2 E1-E4

Typical Performance reflects product at publication t ime exclusive
of EMC data, if any, supplied with product. Specifications are
subject to change without notice.

Power to Additional

FP-ALC1

2A MAX

PWR BUS

80 mA

CURRENT

Flat-Pak Modules, Total

Current Not to Exceed 2 A

or Available Supply Current

INPUT

INPUT OR OUTPUT MAY BE

WIRED BALANCED OR

UNBALANCED

OUTPUT

+

BALANCED UNBALANCED

INPUT

OR

OUTPUT

+

1) FEED INPUT WITH LOUDEST EXPECTED SIGNAL

2) SET GAIN CONTROL SO "INPUT OVERLOAD" LED
DOES NOT FLASH REGULARLY

TYPICAL SETTING FOR +4dBU INPUT

ADJUSTMENT

TYPICAL PERFORMANCE

Input: 10 kΩ balanced bridging (may be connected unbalanced)
Input Level: +4 dBu (nominal)
Output: 150

Ω

balanced (may be connected unbalanced)
Output Level: +4 dBu
Automatic Level Range: -16 to +14 dBu
Gate Threshold: -18 dBu (20 Hz to 3 kHz)
Frequency Response (excluding AGC): 20 Hz to 20 kHz (+/- 0.75 dB)
THD+N (excluding AGC): < 0.15% (20 Hz to 20 kHz)
Noise: < -90 dB (below +4 dBu output)
Headroom: > 18 dB
Indicator (1):

INPUT OVERLOAD

Power Requirement: 24 Vdc @ 80 mA, Ground-referenced
Overall Dimensions: Height: 1.42 in. 3.61 cm
Width: 3.25 in. 8.26 cm
Length: 5.75 in. 14.61 cm

891-2085B

Radio Design Labs Technical Support Centers

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

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