RDL STMX2 Specifications

STICK-ON® SERIES

Model ST-MX2
Universal Audio Mixer

ANYWHERE YOU NEED...

•

Two Channel Audio Mixing

•

Mixer with Selectable Mic or Line Level Inputs

•

Mixer with Simultaneous Mic and Line Outputs

•

To Add Additional Inputs to an Existing Mixer

•

Audio Output Level Metering

•

Balanced or Unbalanced Inputs and Outputs

•

Low Noise and Low Distortion Performance

You Need The ST-MX2!

The ST-MX2 is part of the group of versatile STICK-ON products from Radio Design Labs. STICK-ONs feature the
advanced circuitry for which RDL products are known, combined with unequalled versatility in mounting possibilities.
The durable adhesives provided with the ST-MX2 permit permanent or removable mounting. Numerous available
mounting accessories, brackets, rack-mount and tabletop chassis are optionally available to facilitate any system.

FUNCTIONAL DESCRIPTION: The ST-MX2 is a two channel audio mixer. Each input channel is identical. Pin
jumpers adjacent to each audio input permit the installer to set that input for either mic or line level. The mic input
accepts low impedance balanced microphones (150 Ω nominal) or high impedance unbalanced microphones
(5-kΩ-nominal). The line inputs are 20 kΩ bridging and accept either unbalanced or balanced audio signals. A
single-turn trimmer is provided for each input channel. The usual range of mic or line level signals may be adjusted to
produce +4dBu at the line level output. The dual LED audio meter provides accurate dynamic level adjustment
without an external meter. A separate mic level output is also provided.

The dual LED output meter follows standard VU ballistics. A green LED illuminates at 15 dB below +4 dBu. The
intensity of the green LED progresses from minimum at -11 dBu to full intensity at +4 dBu. The adjacent red LED
illuminates at +4 dBu. The audio may be adjusted for maximum intensity of the green LED. Flashing of the red LED is
equivalent to a VU meter needle swinging above the 0 level.

Unbalanced audio inputs are converted in the module to balanced. Mic level inputs are preamplified to line level.
Either input may be turned down if it is not used. The combination of input levels, individual input adjustments and
output levels makes the ST-MX2 suited to a wide variety of mixing, summing, preamplification and audio format
conversion applications.

TYPICAL APPLICATION: The ST-MX2 is used in any application requiring mixing of two audio sources. A mic may
be mixed with a line level music source. Two mics may be mixed to feed the mic or line level input of a power
amplifier in a meeting room or choir loft. A mic or professional +4 dBu line level mono sum is possible from stereo
CD players, cassette decks, computer sound cards, televisions, and a wide variety of other unbalanced sources. If a
single input channel is used, the ST-MX2 may be used to convert mono line level signals from consumer to
professional, or from professional to consumer format. It may also be used as a microphone preamplifier, or
conversely to adapt unbalanced or balanced line level signals into the microphone input of other equipment.

The audio clarity, low noise, low distortion and versatility make this module ideally suited to a wide variety of
demanding audio applications. Use this module in conjunction with other RDL modules as part of a high quality,
flexible audio/video system.

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

STICK-ON® SERIES

Model ST-MX2
Universal Audio Mixer

OUTPUTS

A

MIC

INSTALL

JUMPERS

FOR

MIC-LEVEL

SOURCE

BALANCED
MIC-LEVEL

(DYNAMIC)

EACH INPUT OR OUTPUT MAY BE BALANCED OR UNBALANCED

GAIN A GAIN B

INPUT A

SIGNAL

FEEDING
BALANCED
LINE-LEVEL

SIGNAL

FROM

SOURCE

EQUIP.

BALANCED UNBALANCED

LINE

PWR IN

MIC

SIGNAL

FEEDING
BALANCED
MIC-LEVEL

EQUIP.

INPUT B

MIC

SIGNAL

FROM

BALANCED

LINE-LEVEL

SOURCE

B

JUMPERS

LINE-LEVEL

SOURCE

ADJUST
LEVELS
ON
METER

LEVEL +4 dBu

PARK

FOR

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.

OUTP

INPUT A

TYPICAL

INPUT

GAIN A

PWR

LINE

TYPICAL

UNBALANCED

OUTPUT

A

MIC

UNBALANCED

DUAL MIC PHANTOM ADAPTER

PHANTOM VOLTAGE ADJUSTMENT

MIC 1

MIC OUT

SIGNAL

FROM
BALANCED
MIC-LEVEL

SOURCE

TYPICAL PERFORMANCE

Inputs (2): Selectable mic or line
Input range for +4 dBu output:
Mic: -45 dBu to -65 dBu; max input: -28 dBu
Line:
Input impedance: Mic: 200 Ω; Line: 20 kΩ bridging
Input or output configuration: Balanced or unbalanced
Outputs (2): MIC and LINE
Output impedance: 150 Ω (mic or line)
Frequency Response:
Mic: 25 Hz to 50 kHz (+/- 1 dB)
Line: 10 Hz to 30 kHz (+/- 0.25 dB)
THD+N:
Mic: < 0.05% (25 Hz to 20 kHz)
Line: < 0.005%
IMD: < 0.004%
Output Level: Mic: -45 dBu; line: +4 dBu

891-1075

MIC

POWERED MIC CONNECTION

AS PHANTOM VOLTAGE SOURCE)

-18 dBV to +10 dBu max input: +22 dBu

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

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

PWR

MIC 2

OUT

THE ST-MPA2 AND

ST-MX2 MAY

OPERATE FROM

THE SAME

POWER SUPPLY

(USING ST-MPA-2 MODULE

Radio Design Labs Technical Support Centers

GAIN

A

INPUT A

MIC

OUTPUTS

A

INPUT A

MIC

SUPPLY

WIRING

GAIN A GAIN B

LINE

24 VDC

POWER

SOURCE

PWR IN

MIC

INPUT B

RDL PS-24

B

MIC

TYPE

SUPPLY

Headroom:
Mic Input: > 22 dB (rel. –50 dBu)
> 32 dB (rel. –60 dBu)
Line Input: > 18 dB (rel. +4 dBu)
Output: > 20 dB (rel. +4 dBu)

Noise:
Mic: < -70 dB (150 Ω source; rel. +4 dBu)
< -80 dBA (200 Ω source; rel. +4 dBu)
(mics set to 50 dB gain)
Line: < -90 dB (referred to +4 dBu)
CMRR:
Mic: > 65 dB (50 Hz to 120 Hz)
Line: > 45 dB (50 Hz to 120 Hz)
Power Requirement:

24 to 33 Vdc @ 60 mA, Ground-referenced