rauland DAX60 Manual

Installation and Service KI-1480B
DAX60 60-Watt Power
Amplifier
DAX120 120-Watt Power
Amplifier
Rauland-Borg Corporation
Issued: 07/08/98
Page 1 of 18

Copyright 1998 by Rauland-Borg Corporation, all rights reserved.
This document contains user’s information on technology that is proprietary to Rauland-Borg
Corporation. Permitted transmittal, receipt, or possession of this document does not express license or
imply any rights to use, sell, design or manufacture this information. No reproduction, publication, or
disclosure of this information, in whole or in part, shall be made without prior written authorization from
an officer of Rauland-Borg Corporation.
©Rauland-Borg Corporation
Rauland-Borg Corporation
3450 West Oakton Street
Skokie, Illinois 60076-2958
[phone]
www.rauland.com

Table of Contents
GENERAL INFORMATION.............................................................................................................................................. 4
DESCRIPTION ..................................................................................................................................................................... 4
REVISION HISTORY............................................................................................................................................................. 4
DRAWINGS, DIAGRAMS, AND OTHER GRAPHICS.................................................................................................................. 5
PACKING LIST/UNPACKING PROCEDURE.............................................................................................................................. 5
INSTALLATION ................................................................................................................................................................... 5
Rack-Mounting ............................................................................................................................................................. 6
Turret-Mounting (DAX6O only) .................................................................................................................................... 6
Input Connections......................................................................................................................................................... 7
Output Connections....................................................................................................................................................... 7
Selecting Balanced or Unbalanced Output Connections................................................................................................. 7
Grounding the Center Tap............................................................................................................................................. 8
Split-Center-Tap Operation........................................................................................................................................... 8
Auxiliary DC Power Supply........................................................................................................................................... 8
POWER CONNECTION.......................................................................................................................................................... 9
Converting the Amplifiers to 240 VAC........................................................................................................................... 9
SETTING THE "INPUT LEVEL”CONTROL .............................................................................................................................. 9
REPLACING THE FUSE......................................................................................................................................................... 9
INITIAL TROUBLESHOOTING...............................................................................................................................................10
SERVICE INFORMATION...............................................................................................................................................11
Locating the Test Points...............................................................................................................................................11
Measuring DC Voltages...............................................................................................................................................11
Measuring AC Voltages................................................................................................................................................12
Locating the Driver and Power Transistors ..................................................................................................................12
Removing and Replacing Transistors............................................................................................................................13
Testing Transistors.......................................................................................................................................................14
DAX6O Circuit Description .........................................................................................................................................14
DAX12O Circuit Description........................................................................................................................................14
APPENDIX A: LIMITED WARRANTY/SERVICE POLICY..........................................................................................17
LIMITED WARRANTY.........................................................................................................................................................17
SERVICE POLICY................................................................................................................................................................18

NKI1480B DAX60 and DAX120 Amplifiers —Installation
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General Information
Description
The Rauland DAX Series amplifiers are designed for use with Rauland's
institutional program and communication Systems. They offer high-quality sound
and dependability. They can be driven to their rated power output by an input
signal as low as 0.3 volts. Their transformer-isolated, 25-volt balanced output
matches the output of Rauland's communication panels; they also have a 70.7-volt
balanced output. Their outputs can operate with a split center tap with Rauland's
Telecenter®5000 and Responder®3000 systems. The amplifiers are listed by
Underwriters Laboratories.
The DAX amplifiers offer helpful power connections for related equipment: three
120-VAC three-pin grounded outlets, and a floating auxiliary DC power output (28
VDC, 1.2 A) that can be used for Rauland's Director Series control panels,
preamplifiers, graphic equalizer, and other equipment.
The amplifiers come with black-enamel face panels. Optional brushed-chrome
dress panels-the RP2525 (DAX6O) and RP2700 (DAX12O)—are available.
Revision History
This manual has been reformatted. No substantial changes were made during the
reformatting process.
1

NKI1480B DAX60 and DAX120 Amplifiers —Installation
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Drawings, Diagrams, and Other Graphics
This document includes the following drawings, diagrams, and/or supplemental
graphics:
9 Transistor Replacement Drawing—Exploded (IL0253)
Packing List/Unpacking Procedure
Although the amplifier was thoroughly checked at the factory, we recommend that
you inspect the amplifier, the enclosed parts, and the shipping container for signs of
improper handling during shipment. In case of damage, immediately place a claim
with the dealer, the distributor from whom you purchased the unit, or—if the unit
was shipped directly to you—with the carrier.
The following parts are included with the amplifier:
Quantity Part Part Number
4Rack-mounting screws for tapped holes (10-32
x ½ hex-head, SEMS, unslotted, machine) WA202
4 Rack-mounting screws for untapped holes (10
x ½ pan-head, slotted, thread-forming) WA102
4#10 Tinnerman “U” type speed nuts for
untapped rack holes AB1889
Installation
The amplifier should be rack-mounted where there is adequate ventilation, a
moderate temperature, an AC power outlet, and provisions for grounding.
The rack should have the standard 19-inch width and a vertical space of at least 5
1/4 inches (DAX6O) or 7 inches (DAX12O). It is recommended that additional
space be left above and below the amplifier to prevent hum from being introduced
into adjacent equipment (such as preamplifiers), to provide additional ventilation,

NKI1480B DAX60 and DAX120 Amplifiers —Installation
Page 6 of 18 (Jul-98)
and to allow easier access for servicing. Allowing an inch of space behind the
amplifier for connections, the rack requires a total depth of seven inches. A cooling
fan is recommended when the rack is enclosed and any of the following conditions
exists:
9
The combined rated output power of all the equipment exceeds 250 watts
RMS; or
9
The input from the AC power line exceeds 500 watts; or
9
Restricted air flow in the rack may create extreme heat.

Important:
Failure to observe the preceding precautions could result in overheating that could
damage the equipment or create a fire hazard.
Rack-Mounting
The DAX Series amplifiers are designed to be mounted into a standard 19-inch
rack. #10 "U" nuts (AB1889) and two kinds of mounting screws are supplied with
each amplifier.
1.If the rack's holes are untapped, select the #10 thread-forming screws
(WA102). Push the #10 "U" nuts, their flat side facing outward, onto the
proper holes in the rack. (you may have to leave the "U" nuts off if the holes
are extruded).
2.If the rack's holes are tapped, select the #10 machine screws (WA202).
Turret-Mounting (DAX6O only)
The rack-mounting procedures can be used to install the DAX6O in a Rauland
Control Turret. However, if the turret’s internal rails are used and the amplifier is
oriented with its front panel facing the rear of the turret, an optional MK1O
Mounting Kit will be needed. This special-order kit must be installed by factory-
trained personnel.

Important:
9
Do not connect AC power to the amplifier until all of the necessary input and
output connections have been completed.
9
Do not disconnect the third wire on the power plug. This wire grounds the
amplifier's chassis to prevent a possible shock hazard. If an adapter is used to
connect the plug to a two-prong socket, make sure that the amplifier’s chassis
is connected to a proven earth ground.

NKI1480B DAX60 and DAX120 Amplifiers —Installation
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Input Connections
The input is unbalanced. The input screw terminals are labeled "COM" (-) and
"INPUT" (+), respectively. The terminal strip is located on the lower right corner,
as viewed from the rear of the chassis. The signal source should deliver at least 300
millivolts into a 13-kilohm load.
To prevent coupling, route the input cables as far from the speaker cables as
possible.
Output Connections
The output screw terminals are located on the upper right corner, as viewed from
the rear of the chassis. The following illustration shows how the output
transformer's split windings are connected with a factory-installed link for most
applications (for applications with the link removed, see "Split-Center-Tap
Operation," below).
Figure 1
The output impedances are as follows:
DAX60 70.7V = 83.3 ohms 25V = 10.4 ohms
DAX120 70.7V = 41.6 ohms 25V = 5.2 ohms
Selecting Balanced or Unbalanced Output
Connections
The balanced outputs for 70.7 volts and 25 volts are for speakers designed for
constant-voltage lines. Each speaker must have a line-matching transformer, and
the speakers must be connected in parallel. The impedance taps on the primaries of
the line-matching transformers indicate how much power will be taken from the
line. Speakers can be added as required until the total wattage absorbed by all of
the transformers is equal to the rated power output of the amplifier. However, it is
good practice to allow an amplifier a headroom of 10% to 20%. For a 60-watt

NKI1480B DAX60 and DAX120 Amplifiers —Installation
Page 8 of 18 (Jul-98)
amplifier, the maximum speaker load should be approximately 50 watts; for a 120-
watt amplifier, the maximum speaker load should be approximately 100 watts.
For unbalanced operation, place a jumper between one of the speaker terminals
and “GND." Do not ground the center tap when you use unbalanced operation.
Grounding the Center Tap
If required by the installation, the center-tap terminals may be jumpered to the
"GND” terminal when the balanced speaker output is used. The "GND" terminal is
next to the negative "AUX POWER" terminal on the DAX6O; on the DAX12O,
the "GND" terminal is next to the "COM" input terminal. When the two center-tap
terminals are linked together, either one of them may be connected to the "GND"
terminal.

Important:
Do not install a jumper between "GROUND" and "CT" with the unbalanced
speaker connection: connecting both points to "GROUND" would create a short
circuit across the output transformer
Split-Center-Tap Operation
The amplifier output transformer can be configured for split-center-tap operation
with symmetrical output voltages on both sides of the center tap. This is intended
for special applications with Rauland systems such as the Telecenter®5000 and the
Responder®3000. When a DAX amplifier is used with the TC5OOO or the
NCS3OOO, (a) no more than 50 watts of power may be drawn through the system,
and (b) a TC5007 Transformer Module is required (see KI-1486).
If the installation requires an isolated, split-center-tapped output, remove the
supplied link from the two "CT" terminals; this will separate the two halves of the
output windings (see "OUTPUT CONNECTIONS," above, and the attached
KMO7BO).

Important:
There is a large capacitor inside the TC5OOO and the NCS3OOO that provides a
low AC impedance across the center taps. The split windings are not designed to
be used independently.
Auxiliary DC Power Supply
The 28-VDC terminals (on the right side of the DAX6O; below the output
transformer of the DAX12O) can provide up to 1.2 Amperes to preamplifiers,
Director Series control panels, and other auxiliary devices requiring DC power.
Since this supply is floating, it can also be used for devices requiring an isolated

NKI1480B DAX60 and DAX120 Amplifiers —Installation
Page 9 of 18 (Jul-98)
power source, such as Rauland's Model 6430 Pink-Noise Source and Model 6431
1/3-Octave Equalizer. Do not mix floating and grounded accessories.
Power Connection
Plug the power cord into a 120-V, 60-Hz, three-wire grounded outlet that can
provide at least 935 watts (DAX6O) or 11O5 watts (DAX12O). Although the
amplifier circuits by themselves consume no more than 175 watts (DAX6O) or 345
watts (DAX120), connecting another device to the DC output could consume
another 40 watts of power, and a total load of 720 watts could be connected to the
three AC sockets. Check the local regulations before installing permanent AC lines
and plugging in the equipment.
Converting the Amplifiers to 240 VAC
If operation from a 240-VAC power source is desired, remove the front cover and
locate the "120V/240V" switch inside the amplifier, on the right. Use a small
screwdriver to slide the switch to the "240V" side. Re-secure the front cover.
Replace the fuse with a fast-blow, 240-volt fuse with half the current rating of the
supplied fuse; the new value would be 1.25 Amps for the DAX6O, 2.5 Amps for
the DAX12O (see "REPLACING THE FUSE," below). Replace the plug on the
power cord with one approved for 240-VAC operation.

Important:
When the amplifier is connected to a 240-volt supply, its three "120 VAC"
convenience outlets will supply 240 volts. Accordingly, they should not be used
when the amplifier is connected to 240 volts

Setting the "Input Level” Control
The input-level control, marked "LEVEL" on the rear chassis below the output
transformer, can be adjusted with a 1/4-inch flat-blade screwdriver: turning the
control clockwise will increase the output level. This control should be set so that
the maximum possible input signal will not cause the output to clip. After this
control has been adjusted by the installer, it should be left alone.
Replacing the Fuse
A current surge during operation may cause the fuse to blow. To restore power to
the amplifier, first ascertain what the problem is and correct it before replacing the

NKI1480B DAX60 and DAX120 Amplifiers —Installation
Page 10 of 18 (Jul-98)
fuse. Use a fast-blow fuse: 2.5 Amps for the DAX6O, 5 Amps for the DAX12O
(but only half of these values if the amplifier is operating from a 240-VAC line).
The fuse holder is on the rear of the amplifier, below the power transformer. You
will need a Phillips screwdriver to remove the center plug; you may find a scissors-
nosed pliers helpful in removing the fuse. If the replacement fuses continue to
blow, unplug the amplifier and consult a qualified service representative.
Initial Troubleshooting
Consult the following troubleshooting table when experiencing any difficulties:
Problem Possible Causes
Low volume or distorted sound.
Check whether all the input and output
connections are properly made and fastened.
Turn the volume down to determine if the
speakers are being overdriven.
Amplifier does not operate.
Make sure the power cord is plugged in to an
operating outlet.
Examine the input and output lines for (1)
obvious shorts (among themselves and between
them and the chassis or surrounding equipment)
and/or (2) broken connections.
Replace the fuse, if all else checks out.
Unplug the unit and contact your local
distributor (if all else fails).
The 28-VDC output cycles off
and on, or remains off.
There are two circuit breakers protecting this
output. CB2 is a 1.6-Amp thermal breaker that
shuts down the circuit when the DC current
flow significantly exceeds the output’s 1.2-
ampere rating, then automatically resets. It will
continue cycling off and on until the problem is
corrected. If the amplifier remains off, CBl
(3.15 Amps) may have tripped. Check for a
short in the connections; then try manually
resetting CB1—by poking a small screwdriver
through the access hole in the front cover (at the
upper left corner of the DAX6O,or the lower
left corner of the DAX12O).
If the problem does not lie in the load or the
connections, one of the breakers may be
defective. Disconnect the load and call your
Rauland distributor.