RDL STM1 Data Sheet

STICK-ON® SERIES

Model STM-1
Mic to Line Level Preamplifier

ANYWHERE YOU NEED...

• Stick-On Convenience

• High or Low Impedance Mic Inputs

• To Convert Line Inputs to Mic Inputs

• Balanced or unbalanced Outputs

• Separate Phantom Supply Input

• RF Filtered Inputs and Outputs

• Excellent Performance

You Need The STM-1!

The STM-1 is part of the group of STICK-ON products from Radio Design Labs. The STM-1 is a quality
microphone preamplifier designed for use in commercial sound, broadcast, and recording applications.
Its compact size makes it ideally suited to locations where 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-1 the ideal choice for both permanent and mobile equipment installations. Some
features of the STM-1 are:

• Balanced microphone input accepts impedances from 150 to 600 Ω

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

monitoring applications

• Fixed 50 dB gain and ample headroom allow operation with any mic

• Phantom supply input terminals allow connection of phantom power when STM-1 is used with

condenser microphones

• Supply input is single-ended and operates from 24 Vdc to 33 Vdc (9 Vdc at reduced headroom)

• Two separate outputs provide for balanced 600 Ω and unbalanced 10 kΩ

• No lugs required for reliable connections

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

• Use STM-1 in conjunction with other RDL STICK-ONs to make complete audio systems

Anywhere you need a fixed gain mic to line preamplifier, STM-1 is the reliable and cost-effective solution!
Use the STM-1 with other RDL RACK-UP®, STICK-ON®, TX™, or FLAT-PAK™ series products as part of
a complete audio/video system.

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

STICK-ON® SERIES

Model STM-1
Mic to Line Level Preamplifier

ALTERNATE INPUTS

INPUT PHNTM

SPEAKER

SIGNAL

FROM

UNBALANCED

MIC-LEVEL

SOURCE

INPUT

MICROPHONE PREAMPLIFIER

PHNTM OUTPUT

USED AS

MIC

MIC TO LINE LEVEL

HI - Z LO - Z

PWR OUTPUT

PHNTMINPUT

AUDIO

WIRING

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.

MICROPHONE PREAMPLIFIER

INPUT

SIGNAL

FROM
BALANCED
MIC-LEVEL

SOURCE

INPUT

MIC TO LINE LEVEL

PHNTM OUTPUT

FEEDING

UNBALANCED

LINE-LEVEL

EQUIPMENT

MICROPHONE PREAMPLIFIER

PHNTM OUTPUT

HI - Z LO - Z

PWR OUTPUT

SIGNAL

MIC TO LINE LEVEL

HI - Z LO - Z

PWR OUTPUT

BALANCED

LINE-LEVEL

EQUIPMENT

SIGNAL

FEEDING

OPTIONAL JUMPER

BATTERY

-+

OR EXTERNAL

PHANTOM

24 VDC

POWER

SOURCE

TO PROVIDE PHANTOM

VOLTAGE TO CONDENSER

MIC WHICH CAN USE UP

TO 32 VOLTS PHANTOM

SUPPLY

(UP TO 48V)

NOTE THE STM-1 WILL OPERATE (WITH REDUCED HEADROOM) ON
SUPPLY VOLTAGES FROM 9 VDC TO 23 VDC.

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 impedance
Frequency Response: 50 Hz to 30 kHz (+/- 1.0 dB)
Gain: 50 dB nominal
THD+N: < 0.050%
CMRR: > 60 dB (50 Hz to 30 kHz)
Headroom: > 20 dB (24 Vdc supply); 14 dB (12 Vdc supply)
Noise: < -70 dB (below +4 dBu 150 Ω source)
< -75 dB (below +4 dBu 600 Ω source)
Power Requirement: 24 to 33 Vdc @ 25 mA, Ground referenced
(9 Vdc operation with reduced headroom)

Radio Design Labs Technical Support Centers

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

891-0014I

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

24 VDC

POWER

SOURCE

THIS
TERMINAL
IS COMMON
GROUND