RDL RUMLA2T Quick Start Guide

RACK-UP® SERIES

Models RU-MLA2 & RU-MLA2T

Dual Mic/Line Preamplifier

ANYWHERE YOU NEED...

• Two-channel Audio Preamplifier

• Front Panel XLR Input / Output Jacks

• Detachable Input / Output Terminal Blocks

• Switch-selectable Mic or Line Inputs

• Switch-selectable Mic Gain and Phantom

• Gain Trim on Each Input

• Each Output Switch-selectable Mic or Line

You Need The RU-MLA2!

The RU-MLA2 is part of the group of RACK-UP products from Radio Design Labs. RACK-UPs feature the
advanced circuitry for which RDL products are known, combined with accessible user-friendly controls and

displays. The ultra compact design permits high-density installations, with three products mounted in a single

rack unit. Optional brackets permit mounting a RACK-UP module above, below, or in front of any flat surface!

APPLICATION: The RU-MLA2 is a dual channel audio preamplifier. The inputs and outputs may be

connected through the front-panel XLR jacks or on the rear panel detachable terminal blocks. Each input
accepts either a balanced microphone or line level signal. Each output provides either a microphone or
line level signal. Both the front-panel XLR connectors and the rear-panel terminals are active at all times.
The RU-MLA2 may be rack-mounted with the XLR jacks facing forward, or may be reverse-mounted using
the RDL RU-FP1 Filler Panel/Reverse Mount Kit.

Each audio input is equipped with a rear-panel switch to select between MIC and LINE level. Two
additional switches on each input allow setting the MIC input for LO or HI gain and for enabling or
disabling standard 24 Vdc phantom. The two microphone gain settings allow the connection of a wide
variety of dynamic and condenser microphones. Each output is provided with a separate rear-panel switch
to set the associated level to either MIC or LINE. Audio outputs may be wired balanced or unbalanced.
Crosstalk between channels is below the noise floor, allowing the RU-MLA2 to be operated as a stereo
preamplifier or as two separate mono preamplifiers.

Gain trim for each channel is provided on a front-panel control. The knurled adjustment includes a slot so
the gain may be adjusted by hand or by screwdriver. An RDL Dual-led VU meter is provided above each
channel gain trimmer. The meters are calibrated to indicate +4 dBu for outputs set to line level.

The rear panel provides a detachable terminal block and a power input jack to connect 24 Vdc power. The
RU-MLA2 audio outputs are active balanced. Each output of the RU-MLA2T is equipped with a
studio-quality audio output transformer.

Wherever a dual channel mic and line level audio preamplifier with gain trim is needed to provide superior
audio clarity, user adjustments, reliability, compactness and unsurpassed versatility, the RU-MLA2 is the
ideal choice. Use the RU-MLA2 combined with other RDL RACK-UP, STICK-ON, TX™, or FLAT-PAK™
series products as part of a complete audio/video system.

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

RACK-UP® SERIES

Model RU-MLA2
Dual Mic/Line Preamplifier

Installation/Operation

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

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

CORRECT LEVEL
WITH GREEN BRIGHT
AND RED FLASHING
OCCASIONALLY

SET INPUT GAIN
FOR CORRECT
LEVEL ON DUAL-LED
METER

SET INPUT FOR
MIC OR LINE LEVEL

TYPICAL PERFORMANCE

LEVEL

+4

GAIN

INPUT A

MIC/LINE

RDL RU-MLA2

LIIM

N

C

ML

HIOLFOFNO

GAIN PHM

TURN PHANTOM ON FOR CONDENSER, OFF FOR DYNAMIC

SET GAIN F OR MIC INPU T

SET OUTPUT FOR MIC OR LINE LEVEL

OUTPUT A

MIC/LINE

CONNECT MIC OR LINE INPUT TO FRONT OR REAR

CONNECT MIC OR LINE OUTPUT TO FRONT OR REAR

OUTPUT B

OUTPUT A

INPUT B

M = MIC
L = LINE

LEVEL

GAIN

ML

+4

INPUT B

MIC/LINE

MIIL

C

N

ONFOFLOIH

PHMGAIN

OUTPUT B

MIC/LINE

24 VDCINPUT A

MADE IN U.S.A.

CONNECT 24 VDC POWER TO
TERMINAL BLOCK OR JACK

UNBALANCED WIRING

INPUT

OUTPUT

Inputs (2): XLR (3 pin, front panel) and detachable terminal block (rear panel)
Input level (for +4 dBu output): Switch-selectable (rear panel) MIC (LO or HI gain) or LINE

Mic: -48 dBu to -3 dBu (LO GAIN); -65 dBu to -20 dBu (HI GAIN)
Line: -15 dBu to +28 dBu

Input Impedance:
Mic:

2 kΩ balanced, switchable 24 V phantom (IEC 1938: 1996-12)

Line: > 10 kΩ balanced; may be connected unbalanced

Outputs (2): XLR (3 pin, front panel) and detachable terminal block (rear panel)
Output level: Switch-selectable (rear panel) MIC (-46 dBu) or LINE (+4 dBu)
Output Impedance: 150 Ω balanced; drives high or low impedance lines
Channels: 2 (A and B; may be used for stereo or as two separate mono preamplifiers)
Gain Trim (2): Front panel adjustable; one for each channel
Mic

LO GAIN: Off to 52 dB gain

Mic HI GAIN: Off to 69 dB gain

Line: Off to 20 dB gain

Frequency Response:
Mic: 80 Hz to 50 kHz (+/- 0.75 dB); < 10 dB @ 20 Hz (integral high-pass filter)
Line: 15 Hz to 50 kHz (+/- 0.1 dB)
THD+N:

Mic: < 0.1% (80 Hz to 20 kHz)
Line: < 0.005%
CMRR: > 60 dB (Mic); > 50 dB (Line)
Residual Noise (below +4 dBu LINE output or -45 dBu MIC output):
Mic 40dB Gain, LO GAIN: -79 dB (20 Hz to 20 kHz)
Mic 50dB Gain, HI GAIN: -79 dB (20 Hz to 20 kHz)
Mic 60dB Gain, HI GAIN: -70 dB (20 Hz to 20 kHz)
Line: -85 dB (20 Hz to 20 kHz)
Crosstalk: Below noise floor (A to B; B to A)
Headroom (above +4 dBu LINE output): > 20 dB

Power Requirement: 24 to 33Vdc @ 80 mA, Ground-referenced

Radio Design Labs Technical Support Centers

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

891-3215

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