Biamp DA28R User Manual

DA28R

Distribution Amp / Router

Operation Manual

Biamp Systems, 10074 S.W. Arctic Drive, Beaverton, Oregon 97005 U.S.A. [phone] www.biamp.com

an affiliate of Rauland Borg Corp.

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print update

September 7, 2005

TABLE OF CONTENTS

Front & Rear Panel Features

Logic Input & Transformers

Applications

Specifications & Block Diagram

Warranty

pg. 2

pg. 3

pgs. 4 & 5

pg. 6

DA28R

INTRODUCTION

The DA28R is a 2-in by 8-out distribution amp/router. Each input channel
accepts mic or line-level signals, and includes phantom power for condenser
microphones. All outputs are electronically balanced & floating line-level, with
600 ohm drive capability. Logic inputs allow routing of each input to specific
outputs via external contact-closures. The DA28R can operate as a flexible
2x8 distrubution amp, or as a complete 8-zone page-over-music routing
system. The DA28R carries a five-year warranty.

DA28R features include:

♦ two electronically balanced, differential mic/line inputs

♦ pad switch, trim control, & peak indicator on each input

♦ 24 volt phantom power switch on each input channel

♦ eight electronically balanced & floating line outputs

(600 ohm line output drive capability)

♦ screwdriver adjustable level control for each output

♦ sixteen logic inputs with invert function switches

(mute/assign inputs to outputs via external switches)

♦ inputs & outputs on plug-in barrier strip connectors

♦ optional input and output isolation transformers

♦ covered by Biamp Systems’ five-year warranty

♦

marked and UL / C-UL listed power source

1

FRONT & REAR PANEL FEATURES

27V

50/60 Hz

12 watts

class 2 wiring

Input Connectors (Channels 1 & 2): These plug-in barrier strips
provide the balanced mic/line inputs for Channel 1 & Channel 2.
Input isolation transformers (model IT-A) are available as a user
installed option (see Transformers on pg. 3). For balanced input,
wire high (+), low (-), and ground (
high (+), and ground to both (
available for condenser microphones (see DIP Switches below).

Trim (Channels 1 & 2): These screw-driver adjustable controls set
the channel gain (+24dB ~ +60dB) to compensate for different input
signal levels. For best performance, adjust these controls so the
channel +10 indicators flash only on occasional peaks. If input
signal level exceeds the normal operating range of the Trim control,
assign the corresponding channel Pad switch (see below). When
both inputs are assigned to common outputs, it may then be
necessary to reduce the Trim setting on one input, to establish a
proper level relationship (mix) between the two input signals.

Pad (Channels 1 & 2): When depressed, these switches reduce
the signal level at the respective input channels by 40dB. Use the
Pad switches whenever signal level at the associated input channel
exceeds the normal operating range of the Trim control. Typically,
a line-level input signal will require use of the Pad.

+10 Indicator (Channels 1 & 2): These red LEDs will light
whenever channel signal levels reach +10dB (8dB below clipping).
Use this feature to aid in adjusting the Trim controls (see above).

DIP Switches (Channels 1 & 2): These switches assign functions
to the input channels (when pushed up). Phantom
+24VDC phantom power at the respective input, for use with
condenser microphones. CAUTION: Make sure phantom power is
turned off (switch down) when connecting line-level input signal.
Invert Logic
from ‘muting’ the associated channel at Outputs 1~8, to ‘unmuting’
the associated channel at Outputs 1~8 (see Logic Inputs below).

DA28R

~

BIAMP SYSTEMS

Portland, Oregon

an affiliate of Rauland-Borg Corp.

logic inputs output 8 output 7 output 6 output 5 output 4 output 3 output 2 output 1 CH 1

logic inputs

d

). For unbalanced input, wire

d

) & (-). Phantom power (+24VDC) is

turns on

reverses the operation of the respective Logic Inputs,

DA28R

on

INPUTSOUTPUTS

levellevellevellevellevellevellevellevel

phantom

invert logic

CH 2

phantom

invert logic

CH 1

trim

pad

+10

CH 2

trim

+10

pad

Output Connectors (Outputs 1~8): These plug-in barrier strips
provide the balanced line-level signals from Outputs 1~8. Output
isolation transformers (model IT-B) are available as a user installed
option (see Transformers on pg. 3). For balanced output, wire high
(+), low (-), and ground (
and ground (

d

), leaving (-) unconnected. Signal level will be

d

). For unbalanced output, wire high (+)

reduced by 6dB when outputs are unbalanced. Output 1~8 are
assigned signals from Channel 1 and/or Channel 2, by means of
DIP Switches & Logic Inputs (see below). From the factory, signals
from both input channels are assigned to all Outputs 1~8.

Level (Outputs 1~8): These screw-driver adjustable controls
provide level adjustment for the respective outputs. Use the Level
controls individually to set the desired signal level for each sound
system or device being fed. The range of the Level controls is from
‘OFF’ (fully counter-clockwise) to a maximum of +16dB of gain (fully
clockwise). From the factory, all Output 1~8 Level controls are set
fully counter-clockwise, to ‘OFF’.

Logic Inputs (Channels 1 & 2): This 25-pin Sub-D (female)
connector provides Logic Inputs 1~16 (on pins 1~16 respectively)
and a common ground (on pins 17~25). Logic Inputs allow signal
from Channel 1 & Channel 2 to be routed to the various outputs, via
external contact-closures. Logic Inputs 1~8 route Channel 1 to
Outputs 1~8 respectively. Logic Inputs 9~16 route Channel 2 to
Outputs 1~8 respectively. Logic Inputs perform either ‘muting’ or
‘unmuting’ functions, depending upon the position of the ‘Invert
Logic’ DIP Switches (see above). When ‘Invert Logic’ is assigned,
the associated input is normally muted at all outputs, and a contact­closure will ‘unmute’ the input at the desired output. From the
factory, ‘Invert Locic’ is not assigned, both inputs are normally
unmuted at all outputs, and a contact-closure will ‘mute’ the input at
the desired output. Logic Inputs allow a variety of input/output
routing (see Logic Inputs on pg. 3 & Applications on pgs. 4 & 5).

AC Power Cord: The power transformer provides 27 Volts AC to
the DA28R, and is detachable via a 5-pin DIN connector. The
DA28R has two internal ‘self-resetting’ fuses (there are no user
serviceable parts inside the unit). If the internal fuses blow, they will
attempt to re-set after a short period. However, this may be an
indication that the unit requires service.

On Indicator: When the power transformer is plugged in, and AC
power is applied to the DA28R, the red On indicator remains lit.

2