Oxmoor DCA-2 User Manual

DCA-2/DCA-2T DIGITAL CONTROL ATTENUATOR

& RC-16 REMOTE CONTROL

The Oxmoor DCA-2 Digital Control Attenuator™ and
one or more RC-16 Remote Control™ units together
constitute a unique, high-quality system for the re­mote control of audio level. The DCA-2 is a compact
(1-3/4” high) rack mountable package that can control
two discrete audio channels (90 dB of isolation is
provided for two unrelated programs) or the two
channels can be linked to control a single stereo pro­gram. Multiple DCA-2s can be linked, and up to 64
discrete channels can be controlled in a single chain
with 1/4 dB tracking tolerance between channels.

Designed for professional applications, the DCA-2 is
equipped with XLR-type input and output connec­tions. Additionally, Channel A & B maximum gains
can be adjusted ±15 dB from the nominal unity gain of
the system via recessed, front-panel controls. Maxi­mum cable length from the DCA-2 to the farthest
remote is approximately 2,000 feet.

The Oxmoor system includes a number of unique
features. A Preset control on the DCA-2 rear panel sets
the degree of attenuation on power up, avoiding an
unpredictable or unknown turn-on state. One or both
channels can be switch-reset back to this “Preset” level
at any time. Another rear panel control, labeled “Prior­ity,” sets a level to which the system can be temporarily
forced by an external switch closure. Each RC-16 re­mote has terminals for preset and priority functions.
The switch itself is not included.

The DCA-2T outputs are transformer balanced. Either
system is capable of driving 600 ohm or higher imped­ance loads; maximum output is +18 dBm terminated,
+20 dBu unterminated.

21

G

CH. A

SHAFT

ENCODER

3

21

G

3

CUP

CDN

LOGIC

AUDIO

CH. B

RC-16 REMOTE CONTROL

Attenuator

Attenuator Trim Pot

IN OUT IN OUT

IN OUT

Trim Pot

ON-BOARD LOGIC

CH. A

CH. B

PRESET PRIORITY

1

2

3

1

2

3

Block diagram of the DCA-2 and RC-16

Precise volume control can be provided at as many
locations as required. The remote units are easily wired,
in “daisy-chain” configuration, using simple modular
telephone style cables. Up to four RC-16 remotes can
be connected to a given control input (and that remote,
or string of remotes, can be “daisy- chained” to control
up to 64 audio channels). The system provides 29 steps
of precise 1.5 dB attenuation from 0 to -43.5 dB, with a
30th step for 90 dB “full kill” attenuation. Virtual
display of the set attenuation is simultaneously given
at all locations via a circular LED array around the
knob on each RC-16 Remote Control. The RC-16 can be
mounted in a standard two-gang electrical wall box, or
a pre-punched 2-gang plate is available from Oxmoor.

The RC-16 is actually a highly sophisticated shaft
encoder which translates knob movements into a string
of digital pulses; the pulses then alter the level of the
digital attenuator(s) within the DCA-2 chassis. Unlike
up/down buttons, the RCA-16 is sensitive to rate-of­change, and thus the faster the knob is turned, the
faster the setting is changed. As any interconnected
RC-16 knob is turned, the LEDs on all remotes in the
chain follow until the upper or lower limit is reached.
At that point, the knob will continue to turn, but the
level and Virtual Pointers simply stop changing until
any one of the knobs is turned in the opposite direc­tion. Since there are no mechanical stops, a knob can­not be “twisted off” if it is turned beyond what would
be the “stop” positions on a conventional level control.

G

CH. A

G

CH. B

For applications where access to one or more remote

With the Oxmoor RC-16's Virtual Pointer, you

can see where the volume is, wherever you are.

Oxmoor Corporation, LLC, 309 Cahaba Valley Parkway, Birmingham, AL 35124 USA Toll Free: 1-800-262-6898

Phone: [phone] Fax: [phone] E-mail: [e-mail] Internet: www.oxmoor.com

controls must be restricted, a key switch can be
installed in place of a jumper on the back of the RC-16;
the key switch must then close to activate the RC-16.

DCA-2/DCA-2T & RC-16 SPECIFICATIONS

RC-16 REMOTE CONTROL

CONTROLCONTROL

CONTROL Type ................................. Incremental Rotary Bi-Phase Encoder

CONTROLCONTROL

DISPLAYDISPLAY

DISPLAY Light-Emitting Diodes ........ Multiplexed Display Refreshed at Line

DISPLAYDISPLAY

CONTROL LOOPCONTROL LOOP

CONTROL LOOP Max. Controls Per Ch ........ 4

CONTROL LOOPCONTROL LOOP

LOCKOUTLOCKOUT

LOCKOUT Key-Switch ........................ Single-Pole Dry Closure, 25 mA

LOCKOUTLOCKOUT

SAFETY LISTINGSAFETY LISTING

SAFETY LISTING City Of Los Angeles

SAFETY LISTINGSAFETY LISTING

MECHANICALMECHANICAL

MECHANICAL Front Dimensions .............. 578 mm (2.28 in) Square

MECHANICALMECHANICAL

Max. Ch. Per Control Loop 64

Max. Cable Length ............ 600m (2000 ft)*

Contact Requirements ....... Single Pole Switch or Open Collector

Wiring Scheme .................. Daisy-Chained Connection Via

Cable and Connectors ....... 6-Wire Modular Telephone type

Rear Dimensions ............... 533 mm (2.28 in) Diameter

Max. Mounting Panel

Thickness ......................... 9.6 mm (0.38 in)

Min. Required Depth ......... 437 mm (1.72 in) Below Front Panel

Finish ............................... Matte Black Injection Molded High-

Weight .............................. Shipping: 454 grams (1.0 lb)

with Quadrature-to-Pulse Conversion
Circuit

Frequency Rate by Serial Data Burst.
One of 16 Concentric Light-Emitting
Diodes (LEDs) is Illuminated as a
Virtual Pointer.

Transistor (128 mA Capacity), Dry
Closure to Logic Ground

Looping Jacks

RJ-11/12

Capacity

203 mm (0.8 in) Above Panel
Surface

406 mm (1.6 in) Below Front Panel
Surface

Surface Including Connectors

Impact Plastic Escutcheon and Knob,
Black Painted Can

Net: 114 grams (0.25 lb)

DCA-2/DCA-2T DIGITAL CONTROL ATTENUATOR

FREQUENCY RESPONSEFREQUENCY RESPONSE

FREQUENCY RESPONSE 20 Hz to 20 kHz ............................. +0, – 0.3 dB

FREQUENCY RESPONSEFREQUENCY RESPONSE

HUM AND NOISEHUM AND NOISE

HUM AND NOISE Unweighted ..................................... - 80 dB (Ref. 0 dBm Output @ Unity Gain)

HUM AND NOISEHUM AND NOISE

DISTORTIONDISTORTION

DISTORTION Ref. +4 dBm Output @ Unity Gain

DISTORTIONDISTORTION

CROSSTALKCROSSTALK

CROSSTALK Channel to Channel ........................ - 90 dB (20 Hz to 20 kHz

CROSSTALKCROSSTALK

AUDIO INPUTAUDIO INPUT

AUDIO INPUT Type ............................................... Electronically Balanced (RF Suppressed)

AUDIO INPUTAUDIO INPUT

AUDIO OUTPUTAUDIO OUTPUT

AUDIO OUTPUT Type - DCA-2 ................................... Electronically Unbalanced, Non-Inverting

AUDIO OUTPUTAUDIO OUTPUT

DIGITAL ATTENUATORDIGITAL ATTENUATOR

DIGITAL ATTENUATOR Control Range ................................. 0 to -43.5 dB in 29 Steps

DIGITAL ATTENUATORDIGITAL ATTENUATOR

CONTROL LOOPCONTROL LOOP

CONTROL LOOP Maximum Controls Per Ch .............. 4

CONTROL LOOPCONTROL LOOP

- 3 dB Points, Ref.1 kHz .................. 4 Hz to 60 kHz (+4 dBm Output)

THD + NOISE .................................. 0.002% (20 Hz to 20 kHz BW)

SMPTE IMD ................................... 0.002% (60 Hz & 7 kHz, Mixed 4:1)

Transient Intermodulation ............... 0.004% (3.15 kHz SQ + 15 kHz Probe,

30 kHz BW)

Input Terminated w/600 Ohms,
Adjacent Channel Driven to 0 dBm)

Connector ....................................... Female XLR

Pin Out ........................................... Pin 1 Shield (Chassis), Pin 2 +, Pin 3 –

Input Impedance ............................. 80 k Ohms

Nominal Input Level ........................ +0 dBu

Maximum Input Level ...................... +20 dBu

Trim Pot Gain Range ....................... ±15 dB (Ref. 0 dBu Output)

Type - DCA-2T ................................. Electronically Balanced, Non-Inverting

Connector ....................................... Male XLR

Pin Out - DCA-2 ............................... Pin 1 (Chassis), Pin 2 +, Pin 3 Shield

Pin Out - DCA-2T ............................. Pin 1 Shield (Chassis), Pin 2 +, Pin 3 –

Source Impedance .......................... 75 Ohms

Recommended Load Impedance ..... 600 Ohms or Greater

Nominal Output Level ...................... 0 dBu

Maximum Output Level
(Ref. 1 kHz @ Rated THD)

Terminated w/600 Ohms ............ +18 dBm

(All Outputs Driven Simultaneously)

Unterminated ...............................+20 dBu

Plus a 90 dB Full Attenuation “Kill” Step

Tracking Accuracy (Ch. to Ch.) ........ Within ±0.1 dB Throughout

Attenuator Range

Preset and Priority Range ................ 15 Steps (of 3 dB each) Plus “Kill”

Maximum Ch. Per Control Loop .......64

Maximum Cable Length .................. 600m (2000 ft)*

Contact Requirements ..................... Single Pole Switch or Open Collector

Transistor (128 mA Capacity), Dry Closure
to Logic Ground

Wiring Scheme ................................ Daisy-Chained Connection Via

Looping Jacks

Cable and Connectors ..................... 6-Wire Modular Telephone Type

RJ-11/12

Printed 7/01

SAFETY LISTINGSAFETY LISTING

SAFETY LISTING UL & CE

SAFETY LISTINGSAFETY LISTING

MAINS POWERMAINS POWER

MAINS POWER Power Requirements ....................... 100 to 125 VAC or 200 to 230 VAC

MAINS POWERMAINS POWER

MECHANICALMECHANICAL

MECHANICAL Overall Dimensions ......................... 44H x 482W x 183D mm

MECHANICALMECHANICAL

Finish ............................................. Textured Black Paint

Weight ............................................ Shipping: 3.8 Kg (8.5 lb)

50/60 Hz; 8 Watts Maximum

(1.72 H x 19 W x 7.18 D in)

Net: 3.1 Kg (6.9 lb)

* Total length based on typical modular telephone cable resistance of 12 ohms per 100m (330 ft).

Specifications subject to change without notice.

Oxmoor Corporation, LLC, 309 Cahaba Valley Parkway, Birmingham, AL 35124 USA Toll Free: 1-800-262-6898

Phone: [phone] Fax: [phone] E-mail: [e-mail] Internet: www.oxmoor.com