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.

blank

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

LOGIC INPUTS & TRANSFORMERS

Logic Inputs: Logic Inputs 1~16 are on pins 1~16, and a common ground is on pins 17~25. Logic Inputs 1~8 affect routing of Channel 1
signal to Outputs 1~8, respectively. Logic Inputs 9~16 affect routing of Channel 2 signal to Outputs 1~8, respectively. Logic Inputs are
triggered by being shorted to ground, usually by means of external switches, relays, logic outputs, or other such contact-closures. However,
they may also be triggered permanently, via a ‘hard-wired’ short to ground (see Applications on pg. 5). Logic Inputs perform either ‘muting’
or ‘unmuting’ functions, depending upon the position of the ‘Invert Logic’ DIP Switches (see diagrams below). From the factory, ‘Invert Locic’
is not assigned on Channel 1 or Channel 2, and both inputs are normally unmuted (turned on) at all outputs. Contact-closures can then be
used to ‘mute’ (turn off) either input at selected outputs. When ‘Invert Logic’ is assigned, the associated input is normally muted (turned off)
at all outputs, and contact-closures can be used to ‘unmute’ (turn on) that input at selected outputs. A combination of ‘Invert Logic’ and
normal (non-inverted) logic operation allows Channels 1 & 2 to provide an override function. With a single switch wired to two corresponding
Logic Inputs (i.e…Logic Inputs 1 & 9), one input may be muted, while the other input is unmuted at the same output. This can be extremely
effective in multi-zone, page-over-music applications (see Applications on pgs. 4).

113

logic inputs

logic inputs

Logic Inputs

pins 1~8

pins 9~16

pins 17~25

1425

assign functions
ch-1 to outputs 1~8
ch-2 to outputs 1~8

common ground

Ch-1 & Ch-2
normally 'on'

(switches mute)

phantom

invert logic

phantom

invert logic

CH 1

CH 2

phantom

invert logic

phantom

invert logic

CH 1

CH 2

Ch-1 normally 'off'
(switches unmute)
Ch-2 normally 'on'

(switches mute)

phantom

invert logic

phantom

invert logic

CH 1

CH 2

Ch-1 normally 'on'

(switches mute)

Ch-2 normally 'off'

(switches unmute)

phantom

invert logic

phantom

invert logic

CH 1

CH 2

Ch-1 & Ch-2
normally 'off'

(switches unmute)

NOTE: The DA28R chassis must be dis-assembled before installing input/output transformers: 1) remove top panel (2 screws at bottom of
each side panel; 1 screw at top-center of rear panel). 2) remove screws from front panel (2 screws at each end). 3) remove hex-nuts from
rear panel (1 hex-nut each side of Logic Inputs connector). 4) remove mounting screws from circuit board (9 screws in front of rear panel
connectors; 2 screws behind each side of front panel). 6) gently pull circuit board forward (front panel comes forward; connectors exit rear
panel). 7) rotate front panel/circuit board upward, away from chassis (leave rear portion of circuit board in chassis, being careful not to strain
power cord connections).

Input Transformers: To install input transformers (see diagram at right): 1) locate

INPUT TRANSFORMERS

transformer positions T1 & T2 on the circuit board (circle areas located in front of input
connectors). T1 is for Channel 1 & T2 is for Channel 2. 2) un-solder & remove the 2
capacitors located within each of the appropriate circle areas. 3) install & solder an input
transformer at each of the appropriate circle areas (transformer pin 1, designated by a red dot,

T1

cap cap

must be inserted into the proper hole, designated by a square). Input isolation transformers
are model IT-A (P/N# 909-0010-01).

Output Transformers: To install output transformers (see diagram at right): 1) locate

OUTPUT TRANSFORMERS

transformer positions T101~T801 on the circuit board (rectangle areas located in front of output
connectors). T101 is for Output 1, T201 is for Output 2, etc. 2) un-solder & remove the 2
jumpers located within each of the appropriate rectangle areas. 3) install & solder an output

R902

transformer at each of the appropriate rectangle areas (transformer pin 1, designated by a red

T101

R901

dot, must be inserted into the proper hole, designated by a square). Output isolation
transformers are model IT-B (P/N# 909-0019-00).

3

APPLICATIONS

EIGHT ZONES OF PAGE-OVER-MUSIC ROUTING

optional music

assign switches

DA28R

27V

~

50/60 Hz

an affiliate of Rauland-Borg Corp.

12 watts

class 2 wiring

background music sourcepaging microphone

COMPACT

DIGITAL AUDIO

zone paging switches

DA28R

BIAMP SYSTEMS

Portland, Oregon

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

logic inputs

levellevellevellevellevellevellevellevel

phantom

invert logic

CH 2

invert logic

CH 1

phantom

+10

INPUTSOUTPUTS

trim

pad

CH 2

paging mic (ch 2)

to equalizers/amplifiers for eight zones of page-over-music

logic inputs set for
inverted operation.

paging microphone

push-to-talk switches

zone 7

zone 8

zone 5

zone 6

zone 3

zone 4

zone 1

zone 2

invert logic

1

2:50

trim

+10

phantom

invert logic

phantom

pad

CH 1

CH 2

logic inputs 9~16

mute the music

logic inputs 1~8
un-mute the mic

Inverted operation of the

'paging mic' logic inputs

allows the microphone

push-to-talk switches

to un-mute the mic signal

at the appropriate outputs.

Non-inverted operation of

113

1425

the 'music' logic inputs

assigns music to all outputs.

Music assign switches may

be added, which will mute

ground

logic inputs

music at specific outputs

(music assign switches

require diode isolation).

4

APPLICATIONS

TWO INDEPENDENT 1x4 DISTRIBUTION AMPS

input/output assignment

via hard-wired jumpers

DA28R

27V

50/60 Hz

12 watts

class 2 wiring

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

levellevellevellevellevellevellevellevel

phantom

invert logic

CH 2

four outputs from input 2 (ch 2) four outputs from input 1 (ch 1)

input/output assignment

via hard-wired jumpers

input 2

trim

phantom

invert logic

pad

+10

CH 1

both ch 1 & ch 2
logic inputs set for
normal operation.

input 1

INPUTSOUTPUTS

CH 2

phantom

invert logic

trim

pad

+10

phantom

invert logic

CH 1

CH 2

logic inputs 9~12

mute input 2 (ch 2)

from outputs 1~4

logic inputs 5~8

mute input 1 (ch 1)

from outputs 5~8

Both inputs (ch 1 & ch 2)

are set for normal operation.

Normal operation allows

both inputs to be mixed and

sent to all eight outputs.

Hard-wired jumpers are then

113

connected to the appropriate

logic inputs, which mute each

input from specific outputs.

1425

Input 1 (ch 1) is muted at

ground

logic inputs

outputs 5~8. Input 2 (ch 2)

is muted at outputs 1~4.

5

SPECIFICATIONS & BLOCK DIAGRAM

Frequency Response (20Hz~20kHz): +0/-1dB Maximum Input: +24dBu

THD+Noise (20Hz~20kHz): < 0.03% Maximum Output (balanced): +24dBu

Noise Floor (20Hz~20kHz @ unity gain): < -75dBu Power Consumption: 10 Watts max.

Maximum Gain (mic in to balanced out): 79dB Dimensions:

Input Impedance (balanced): height 1.75 inches (44mm)

mic input 4.3k ohms width 19 inches (483mm)

line input 5.6k ohms depth 7.5 inches (190mm)

Output Impedance (balanced): 200 ohms Weight: 4.75 lbs. (2.16kg)

DA28R Block Diagram

DA28R Block Diagram

trim

ch 1 bus

mic

preamp

trim

mic

preamp

logic input

routing control

peak

peak

detect

peak

peak

detect

ch 2 bus

output

transformer

level 1

S

level 2

S

level 3

S

level 4

S

level 5

S

level 6

S

level 7

S

level 8

S

(optional)

output

transformer

(optional)

output

transformer

(optional)

output

transformer

(optional)

output

transformer

(optional)

output

transformer

(optional)

output

transformer

(optional)

output

transformer

(optional)

+

com

+

-

com

+

-

com

+

com

+

-

com

+

-

com

+

com

+

-

com

-

-

-

output 1

output 2

output 3

output 4

output 5

output 6

output 7

output 8

input 1
mic/line

input 2
mic/line

com

com

+ 24V

+

-

+

-

phantom

power

+ 24V

phantom

power

pad

-40dB

pad

-40dB

logic inputs

1-16

input

transformer

(optional)

input

transformer

(optional)

6

WARRANTY

BIAMP SYSTEMS IS PLEASED TO EXTEND THE FOLLOWING 5-YEAR LIMITED WARRANTY TO THE

ORIGINAL PURCHASER OF THE PROFESSIONAL SOUND EQUIPMENT DESCRIBED IN THIS MANUAL

1. BIAMP Systems warrants to the original purchaser of new
products that the product will be free from defects in material
and workmanship for a period of 5 YEARS from the date of
purchase from an authorized BIAMP Systems dealer, subject to
the terms and conditions set forth below.

2. If you notify BIAMP during the warranty period that a BIAMP
Systems product fails to comply with the warranty, BIAMP
Systems will repair or replace, at BIAMP Systems' option, the
nonconforming product. As a condition to receiving the benefits
of this warranty, you must provide BIAMP Systems with
documentation that establishes that you were the original
purchaser of the products. Such evidence may consist of your
sales receipt from an authorized BIAMP Systems dealer.
Transportation and insurance charges to and from the BIAMP
Systems factory for warranty service shall be your responsibility.

3. This warranty will be VOID if the serial number has been
removed or defaced; or if the product has been altered,
subjected to damage, abuse or rental usage, repaired by any
person not authorized by BIAMP Systems to make repairs; or
installed in any manner that does not comply with BIAMP
Systems' recommendations.

4. Electro-mechanical fans, electrolytic capacitors, and normal
wear and tear of items such as paint, knobs, handles, and
covers are not covered under this warranty.

Biamp Systems

10074 S.W. Arctic Drive

Beaverton, Oregon 97005

[phone]

5. THIS WARRANTY IS IN LIEU OF ALL OTHER
WARRANTIES, EXPRESS OR IMPLIED. BIAMP SYSTEMS
DISCLAIMS ALL OTHER WARRANTIES, EXPRESS OR
IMPLIED, INCLUDING, BUT NOT LIMITED TO, IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
PARTICULAR PURPOSE.

6. The remedies set forth herein shall be the purchaser's sole
and exclusive remedies with respect to any defective product.

7. No agent, employee, distributor or dealer of Biamp Systems
is authorized to modify this warranty or to make additional
warranties on behalf of Biamp Systems. statements,
representations or warranties made by any dealer do not
constitute warranties by Biamp Systems. Biamp Systems shall
not be responsible or liable for any statement, representation or
warranty made by any dealer or other person.

8. No action for breach of this warranty may be commenced
more than one year after the expiration of this warranty.

9. BIAMP SYSTEMS SHALL NOT BE LIABLE FOR SPECIAL,
INDIRECT, INCIDENTAL, OR CONSEQUENTIAL DAMAGES,
INCLUDING LOST PROFITS OR LOSS OF USE ARISING OUT
OF THE PURCHASE, SALE, OR USE OF THE PRODUCTS,
EVEN IF BIAMP SYSTEMS WAS ADVISED OF THE
POSSIBILITY OF SUCH DAMAGES.

585.0152.00