RDL STM2 Data Sheet

STICK-ON® SERIES

Model STM-2
Mic to Line Level Preamplifier

ANYWHERE YOU NEED...

• Low-Noise Mic Preamp

• Adjustable Output Levels

• High or Low Impedance Mic Inputs

• To Convert Line Inputs to Mic Inputs

• Two Balanced or Unbalanced Outputs

• Separate Phantom Supply Input

• RF Filtered Inputs and Outputs

• Low Distortion Performance

You Need The STM-2!

The STM-2 is part of the group of STICK-ON products from Radio Design Labs. The STM-2 is a quality
microphone preamplifier designed for use in commercial sound, broadcast, and recording applications.
The STM-2 is very flexible with gain adjustment from 0 to 65 dB, two balanced or unbalanced outputs, and
available phantom supply input! Its compact size makes it ideally suited to locations were a larger or
heavier preamp cannot be used. Its performance makes it the best choice, even when larger preamps
could be used! The single-ended supply input makes STM-2 the ideal choice for both permanent and
mobile equipment installations. Some features of the STM-2 are:

• Balanced microphone input accepts impedances from 150 to 600 Ω

• Input circuitry permits connection of unbalanced microphones, or 4 or 8 Ω speakers in intercom or

monitoring applications

• Variable gain (up to 65 dB) and ample headroom allow operation with any mic

• Phantom supply input terminals allow connection of external power when STM-2 is used with phantom

powered microphones

• Supply input is single-ended and operates from 24 Vdc to 33 Vdc (12 Vdc at reduced headroom)

• Two separate outputs are provided for balanced operation

• No lugs required for reliable connections

• Convenience of STICK-ON package yields quick, efficient installation

• Use STM-2 in conjunction with other RDL STICK-ONs to make complete audio systems

Anywhere you need an adjustable mic to line preamplifier, STM-2 is the reliable and cost-effective
solution!

RDL •• P.O. Box 1286 •• Carpinteria, CA., USA 93014 •• [phone] •• FAX [phone] •• http://www.rdlnet.com

STICK-ON® SERIES

Model STM-2
Mic to Line Level Preamplifier

ALTERNATE INPUTS

INPUT PHNTM

SPEAKER

SIGNAL

FROM

USED AS

MIC

UNBALANCED

MIC-LEVEL

SOURCE

EACH OUTPUT MAY BE BALANCED OR UNBALANCED

PROFESSIONAL ADJUSTABLE
MICROPHONE PREAMPLIFIER

G
A

I

N

PHNTMINPUT

OUTPUTS

PWR

PHNTMINPUT

PBA
O
W
E
R

AUDIO

WIRING

25 TURN

GAIN

ADJUST

POWER

WIRING

OR

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.

PROFESSIONAL ADJUSTABLE

INPUT PHNTM
G
A

I

N

SIGNAL

FROM
BALANCED
MIC-LEVEL

SOURCE

G
A

I

N

MICROPHONE PREAMPLIFIER

UNBALANCED

LINE-LEVEL

EQUIPMENT

PROFESSIONAL ADJUSTABLE
MICROPHONE PREAMPLIFIER

PHNTMINPUT

OUTPUTS

A B P

SIGNAL

FEEDING

BALANCED

LINE-LEVEL

EQUIPMENT

OUTPUTS

PWR

SIGNAL

FEEDING

PWR

O
W
E
R

PBA
O
W
E
R

OPTIONAL JUMPER

BATTERY

-+

OR EXTERNAL

PHANTOM

SUPPLY

(UP TO 48V)

NOTE THE STM-2 WILL OPERATE (WITH REDUCED HEADROOM) ON

SUPPLY VOLTAGES FROM 9 VDC TO 23 VDC.

24 VDC

POWER

SOURCE

TO PROVIDE PHANTOM
VOLTAGE TO CONDENSER
MIC WHICH CAN USE UP
TO 32 VOLTS PHANTOM

IS COMMON

THIS

TERMINAL

GROUND

24 VDC

POWER

SOURCE

TYPICAL PERFORMANCE
Input Impedance: 150 to 600 Ω balanced; 5 kΩ unbalanced
Output Impedance: 150 Ω balanced to drive balanced or unbalanced lines of 150 Ω or higher
Output Levels: +4 dBu balanced
Frequency Response: 50 Hz to 25 kHz (+/- 1 dB)
Gain: Adjustable 0 to 65 dB
THD+N: < 0.050%
CMRR: > 60 dB (50 Hz to 30 kHz)
Headroom: > 20 dB (24 Vdc supply); 14 dB (12 Vdc supply)
Power Requirement: 24 to 33 Vdc @ 25 mA, Ground-referenced
(9 to 23 Vdc with reduced headroom)

Radio Design Labs Technical Support Centers

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

891-0015H

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