Radio Systems DA 2x4b User manual

Radio Systems, Inc. DA-2/4x4b Manual
5/07 Page 1
DA 2x4b & 4x4b
Distribution Amplifier
Manual
EMC and Safety Conformity

Radio Systems, Inc. DA-2/4x4b Manual
5/07 Page 3
Contents
Overview ....................................................................... 4
Mounting ....................................................................... 4
Operation ...................................................................... 4
Connections .................................................................. 4
Connection Examples ................................................... 6
Parts Layout Power Supply .......................................... 7
Parts Layout Amplifier.................................................. 8
Parts List Power Supply................................................ 9
Parts List Amplifier..................................................... 10
Specifications.............................................................. 11
Using Active Balanced Circuitry ................................. 12
Warranty ..................................................................... 14
Repair Policy ............................................................... 14
Return Instructions..................................................... 14
Declaration of Conformity .......................................... 15

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Overview
The Radio Systems DA-4x4b is designed to function as a super low noise, low
distortionaudiodistributionamplifierwhich may beuser wired tofunction in various
flexibleinputandoutputconfigurations.
Excellentisolationisprovidedbetweenoutputs. Each balancedchannel,regardless
of level set and load, is unaffected by the other channels. The Radio Systems DA-
4x4bDistributionAmplifier allowsaudio sourcesto beroutedto multiplelocations
withvariouslevelrequirements and impedanceswhilemaintainingthe integrityof
signalqualitythroughout.
Thedistribution amplifier isconfigurable to a dual channel, 2x4 outputversion, or
quadchannel,4x4outputversion.
Mounting
The 4x4b occupies only 1 rack unit (1-3/4 inch) of height in a 19 inch EIA rack. To
allowforadequateventilation,avoidmountingtheunitdirectlyabovelargeheat
producing equipment such as power amps or power supplies.
When stacking units, it is recommended that one rack space (1-3/4 inch) remain
openbetweeneverythreeunits.
Operation
Apply an input level of approximately 0dB to the input terminals. The gain of any
stage may be increased by 20dB in 10dB steps by changing the internal gain straps.
To locate and reset these jumpers, refer to the parts layout for the location of JU1
and JU2. The lid of the unit must be removed to access these jumpers. Place a
shorting strap across the center and rear pin (pin towards the rear barrier strip) to
increase input gain by 10dB. Place a shorting strap across the center and forward
pinto increaseinput gainby 20dB.
Output level is factory set for unity gain. Each output can be individually set via its
front panel recessed level pot over a range from –60 to +18dBm. Nominal
operatinglevelsare0dBminputand+10dBmoutput. Higheroperatinglevelscan
cutdynamic range by operating tooclose totheclipping point. Adjust eachoutput
tothe desiredlevel, keeping clipping in mind.
Connections
The units are primarily designed for balanced inputs and outputs. The input ground
is connected to the chassis and power supply at a single point. If unbalanced lines
are used, tie the unused input terminal to ground. However, do not tie any unused
outputterminalstoground. Wireanunbalancedoutputbetweenoneoutput
terminal and the input ground terminal. For further details, see the section on
usingactivebalancedcircuitryin this manual.
Althoughthe outputs areshort circuit protected,operating into lessthan a 600ohm
load is not recommended. The input is bridging (high impedance) and will not load

Radio Systems, Inc. DA-2/4x4b Manual
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downanysource.
Because the unit is actually four separate 1 input x 4 output amplifiers, internal
jumpersJU3and JU4allow forthe followingconfigurations:
1input x 8 outputs (stereo)
4inputsx 4outputs(mono)
2inputs x 4outputs (stereo)
Additionally,bywiring the inputsinparallel, thefollowingconfiguration ispossible:
1inputx16output(mono)
Refer to the connection diagram on the following page for details.
AC line voltage is user selectable from the lid of the cabinet by inserting a thin
shafted screw driver through the vent holes to move the red line voltage selector
switch to the left for 230V operation, and to the right for 110V operation (factory
default).

Radio Systems, Inc. DA-2/4x4b Manual
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G
4D+ 4D- 3D+ 3D- 2D+ 2D- 1D+ 1D-
G
D Outputs
D+ D- G X X G C+ C-
Inputs
G
4C+ 4C- 3C+ 3C- 2C+ 2C- 1C+ 1C-
G
C Outputs
Connect straps
G
4B+ 4B- 3B+ 3B- 2B+ 2B- 1B+ 1B-
G
B Outputs
B+ B- G X X G A+ A-
Inputs
G
4A+ 4A- 3A+ 3A- 2A+ 2A- 1A+ 1A-
G
A Outputs
Connect straps
Mono
G
4D+ 4D- 3D+ 3D- 2D+ 2D- 1D+ 1D-
G
D Outputs
D+ D- G X X G C+ C-
Inputs
G
4C+ 4C- 3C+ 3C- 2C+ 2C- 1C+ 1C-
G
C Outputs
(No straps)
G
4B+ 4B- 3B+ 3B- 2B+ 2B- 1B+ 1B-
G
B Outputs
B+ B- G X X G A+ A-
Inputs
G
4A+ 4A- 3A+ 3A- 2A+ 2A- 1A+ 1A-
G
A Outputs
(No straps)
Left or Input 1 Right or Input 2
For use as a 1 input x 16 output (mono)
Left or Input 3 Right or Input 4
For use as a 4 input x 4 output (dual stereo or quad mono)
Note: The 2x4 (mono) version uses only the left-hand circuit board. Configure it as shown above for:  Illustration 1 - 1 input x 8 output (mono)  Illustration 3 - 2 input x 4 output (stereo)
G
4D+ 4D- 3D+ 3D- 2D+ 2D- 1D+ 1D-
G
D Outputs
D+ D- G X X G C+ C-
Inputs
G
4C+ 4C- 3C+ 3C- 2C+ 2C- 1C+ 1C-
G
C Outputs
Connect straps
G
4B+ 4B- 3B+ 3B- 2B+ 2B- 1B+ 1B-
G
B Outputs
B+ B- G X X G A+ A-
Inputs
G
4A+ 4A- 3A+ 3A- 2A+ 2A- 1A+ 1A-
G
A Outputs
Connect straps
Left Right
For use as a 2 input x 8 output (stereo)
Illustration 1 Illustration 3 Illustration 2

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Parts Layout Power Supply

Radio Systems, Inc. DA-2/4x4b Manual
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PartsLayoutAmplifier

Radio Systems, Inc. DA-2/4x4b Manual
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Parts List Power Supply
Part# Qty. Description ReferenceDesignation
16298 1 DA4X4BPOWERSUPPLYDETAIL
1026 2 CAP 15UF 35V C1;C6
10597 2 CAP4700UF 35V C2;C5
5744 2 CAP100UF25VRAD+/-20% C3;C7
5743 2 CAP.1UFFILM C4;C8
7012 8 DIODE1N4005 D1;D2;D3;D4;D5;D6;D7;D8
10489 1 FUSEHOLDER F1
10847 1 FUSE 0.3 AMP F1
10491 1 IECPOWERCONNECTOR J1
10490 1 SAMTEC8PINFRTHEADER J2
2831 1 RES 1K 1/2W 5% R5
9585 2 RES 237 OHM 1/4W 1% R2;R4
9582 2 RES2.61K 1/4W 1% R1;R3
10492 1 SWITCHPOWERDPDT110/220V SW1
10788 1 TRANSFORMERDATOROID T1
1076 1 VRLM337T U2
1077 1 VRLM317T U1
10683 1 LED3MMGREENHIGHCURRENT D9

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Parts List Amplifier
Part# Qty. Description ReferenceDesignation
16295 1 DA4X4BSMT DETAIL
16019 20 RES SMT 1.0K 1/8W 1% R1-R8;R53-60;R62;R63;R151;R155;R159;R163
16350 32 RES SMT 30.1 OHM 1/8W R9THRUR40
16074 8 RES SMT 20.0K OHM 1/8W R41;R42;R44;R44;R45;R47;R48;R50;R51
16022 4 RES SMT 221 OHM 1/8W 1 R61;R55;R58;R64
16351 83 RES SMT 5.11K OHM 1/8W R65-112;114-116;119-121;124-126;129-131;133-
135;137-139;141-143;145;147;198;199;
201;202;204;205;207;208;210;211;213
16351 21 RES SMT 5.11K OHM 1/8W R214;216;217;219;220;222;223;225;226;228;229;
231;232;234;235;237;238;240;241;243;244
16040 16 RES SMT 1.00M OHM 1/8W R169-174;R183-R186;R195;R196;R165-R168
14424 28 RES SMT 2.2K R177;R178;R187-R194;R179;R180;R128;R122;R123;
R113;R132;R117;R118;R127;R149;R153;
R157;R161;R181;R182;R175;R176
16021 4 RES SMT 100K 1/8W 1% R136;R148;R144
16352 8 RES SMT 3.32K OHM 1/8W R150;R152;R154;R156;R158;R160;R162;R164
16353 4 RES SMT 931 OHM 1/8W 1 R43;R46;R49;R52
16354 16 RES SMT 6.04K OHM 1/8W R221;R230;R218;R206;R233;R197;R227;R236;R215;
R224;R239;R209;R203;R242;R200;R212
16355 16 RES SMT 825 OHM 1/8W 1 R245-R260
16005 50 CAP SMT .1UF 50V CERM C1;C12;C15;C24;C35;C38;C47-C54;C95-C98;C115;
C116;C164;C178;C119-C124;C126-C133;C136-C143;
C166;C168;C170;C172;C174;C176
16151 12 CAP SMT 330PF 50V CERM C11;C13;C14;C103;C106;C109;C112;C33;
C34;C36;C37;C10
16346 48 CAP SMT 47PF 50V CERM C87-C94;C79-C85;C147-C162;C86;C180-C195
16347 36 CAP SMT .0022PF 50V CE C17;C19-C23;C4;C25-29;C43-C46;C7-C9;
C30-C32;C18;C99;C5;C100;C101;C6;
C39-C42;C102;C2;C3;C16
14750 32 CAP SMT 22UF 16V ELECT C55-C78;C104;C105;C107;C108;C110;C111;C114
14753 10 CAPACITORSMT100UF C117;C118;C125;C134;C135;C144-C146;C179;C196
16153 8 CAP SMT 100UF 50V ELEC C163;C165;C167;C169;C171;C173;C175;C177
10659 16 POTPIHERPT15LH06-103 R261-R276
16032 16 DIODESMTMMDB4148SOT D1-D16
16356 4 LEDSMTRED D17B;D18B;D19B;D20B
16357 4 LEDSMTGREEN D17A;D18A;D19A;D20A
16348 4 LIGHTPIPE3MMDUALTO D17;D18;D19;D20
16012 4 TRANSISTORSMTMMBT440 Q1;Q2;Q3;Q4
16349 4 IC SMT LM358 U13;U14;U15;U16
16063 28 ICSMTNE5532D U1-U12;U17-U32
11130 4 HEADER15PIN J1-J20
10484 1 HEADER8PINRIGHTANG J21
7903 4 HEADER2PINSINGLERO JU1;JU2;JU3;JU4
7770 4 HEADER3PINSINGLERO JU5;JU6;JU7;JU8
5758 8 JUMPERPLUG.1 JU1;JU2;JU3;JU4;JU5;JU6;JU7;JU8

Radio Systems, Inc. DA-2/4x4b Manual
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Specifications
FrequencyResponse +0,-.1dB20Kz–20kHz
DistortionTHD+N .002%over20Hz – 20kHz,anyoutputlevelfrom
+4dBmto+24dBm(with600ohmload)
DistortionIMDSMPTE .003%anyoutputlevelfrom+4dBmto+24dBm(with
600ohm load)
DistortionDIM .002%anyoutputlevelfrom+4dBmto+24dBm(with
600ohm load)
Crosstalk -105dBover20Hz–20kHz
Noise 102dBbelow+4dBmoutputlevelunitygain
measurementbandwidth 20Hz -20kHz with 600 ohm
inputandoutputtermination
Maximuminput +28dBm
Maximumoutput +25dBm(with600ohmload)
Headroom 21dBabove+4dBmoutput(with600ohmload)
DynamicRange 123dB
MaximumGain jumper selectable for: 16dB, 26dB, or 36dB
CMRR -50dBover20Hz–20kHz
InputImpedance 40kohms
OutputImpedance 60 ohms
LEDAudioInputIndicators -24dBminputlevelaudiopresenttrippoint +24dBm
inputlevelaudiooverloadtrippoint

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UsingActveBalancedCircuitry
Balanced lines have been used for many years and are in continuing use today
because of their immunity to stray pickup. Induced signals appear on both sides of
the balanced line. The receiving end of the balanced line responds only to the
difference voltage between the lines which is the desired signal. Induced signals
are common to both and are balanced out.
Transformers have been the mainstay of balanced circuitry for decades.
Unfortunately,transformerscausedistortionandringing,andaresusceptibleto
magneticfluxpickup. Further, good qualityaudiotransformers areveryexpensive.
The use of op-amp balanced circuitry has the advantage of transformers without
the disadvantages. The only caveat is that careful wiring practices are more
importantwithactivebalancedthanwithtransformers.
Active balanced outputs and inputs use three wires: +, -, and ground. The + and -
terminals are both driven and neither should ever be connected to ground. For
best performance, a three-conductor shielded wire should be used. The third wire
completes the ground circuit. The shield should be connected to the ground at one
end of the wire only. If a two-wire shielded cable is used, it is important that a
groundconnection bemade between thesending andreceiving units. A ground
circuitthrough equipment chassisor through three-prong AC cord ground isalso
acceptable.
Single-endedaudiointerconnectionslacktheinterferenceimmunityofbalanced
hook-ups. Forthe reason, keep unbalanced connections short, direct,and well
separated from AC power wires. To drive a single-ended load from an active
balanced source, use coaxial wire: + to center conductor and ground to shield,
leaving the - output unconnected. To feed an active balanced input from a single-
endedsource, use coaxialwire, connecting thehot center conductor to +. Connect
the shield to ground and put a jumper from ground to -.
Whendriving an activebalanced input froma transformer balanced floating source,
use two conductor shielded wire. Ground the shield at the source end. Establish
goodground betweenthe chassis either directly orthough ACplug ground prongs.
At the load, connect the + lead to the + input and the - lead to the - input. Put two
300 ohm resistors in series between the + input and the - input and connect their
mid-pointto the loadground. This correctly terminatesthe source output
transformerforoptimum frequency andtransientresponse (freedomfromringing)
and provides a low impedance return path for leakage and induced hum. If more
than one active balanced load is to be placed across a floating balanced
transformer source, install this resistive termination once only. From that location
totheactivebalanced loads,runthree-conductor shieldedwire,shieldcontinued
from the sources chassis, + from +, - from -, and ground from the mid-point of the
terminatingresistors.
To drive a balanced floating transformer load from an active balanced source, use
shielded wire. Connect the shield to source ground and leave the shield open at
the load end. Connect + to + and - to -, and establish a good source ground to
load chassis connection, either through a third wire in the interconnect cable or
through chassis contact or AC cord third wire ground.
Interconnectionsbetweenpiecesofstereoequipmentrequiredoublingthe

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connectionsdescribedabovewithoutduplicatingthegroundconnection. Between
piecesof activebalanced stereoequipment, then,5 shielded conductorsshould be
run.
Whentestingactivebalancedequipmentwithsingleendedtestequipment,donot
connectthe -to test equipmentground. Most moderntest equipmentprovides
balancedinputs. In many dual-trace oscilloscopes, balancedsignals may be
displayedby runningthe twoinputs in the“add” modewith oneinput switched to
invert. To perform a test with single-ended equipment, + and - outputs must be
testedindependently and theirresults added. Testing onlya single outputresults in
a 6 db loss in output level.
Theactivebalancedequipmentinterconnectionformatmakes possible stateofthe
art fidelity. Careful attention to detail and conservative practice will be rewarded
withoutstandingflatfrequencyresponse,lowdistortion,andwidedynamic range.

Radio Systems, Inc. DA-2/4x4b Manual
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Warranty
Radio Systems warrants this equipment to be free from defects in materials and
workmanship for a period of one (1) year.
This warranty extends to first users of the product and future owners who purchase
theproductwithinthewarrantyperiod.
The terms of this warranty are null and void if this product is stored or operated in
anenvironment not conducive to electronic equipment, or shows signsof misuse or
modificationswhichaffect theproper functioningofthe product. Thiswarranty
does not apply to damage caused by fire, smoke, flood, lightning, or acts of nature
andphysicalabuse.
RadioSystems,and itsassociated companies,authorizeddistributors, and
personnel are not liable for loss of revenues or other damages or effects to the
broadcast signal quality or coverage which may result from the improper
functioningofthisproduct.
RepairPolicy
Technical assistance is available at any time, at nor charge, by phone or
correspondence.
During the warranty period, there will be no charge for parts or service made to
units which show no sign of misuse by customer or lightning caused damage. The
customer is responsible for the cost of shipping their unit back to Radio Systems for
repair.
During the warranty period, shipment of small parts and assemblies may also be
made at a charge to the user. Emergency shipments of replacement parts and
circuits will be made at the user’s request for an extra shipping and service charge.
Chargeable services will be made COD or on Net-30 day terms to users with
establishedaccounts.
During the warranty period, full credit or return of COD charges (less any service
and expedited shipping charges) will be made to users who return the defective
parts or circuits within 30 days, if the damage is covered under the terms of the
warranty.
ReturnInstructions
ContactRadio Systemsat856-467-8000 fora returnauthorization number.
Pack all items carefully and ship pre-paid, via UPS insured, to:
RadioSystems
601HeronDrive
LoganTownship,NJ08085
Attn: R.A.#_____________
Enclosea note which includes yourname, company, phone number, theserial
number, return address (no box numbers), and a complete description of the
problem.

Radio Systems, Inc. DA-2/4x4b Manual
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DeclarationofConformity
We: Radio Systems, Inc.
601HeronDrive
LoganTownship, NJ 08085 USA
Declareunder our soleresponsibility thatthe product listedbelow:
AudioAmplifier– modelDA-4x4
To which this declaration relates to is in accordance with the following product
standards:
EN55013–Emission
EN55020–Immunity
EN61000 – Harmonic/Voltage Fluctuations
EN60065 – Product Safety
Following the provisions of:
89/336/EEC–EMCDirective
92/031/EEC– Amendment Directiveof 89/336/EEC
73/023/EEC – Low Voltage Directive
93/068/EEC– Amendment Directiveof 73/023/EEC
______________________ _______________________
DateIssued Signature
dd
dd
danieanie
anieanie
aniel J. bravermanl J. braverman
l J. bravermanl J. braverman
l J. braverman
February1, 1997

For Assy:
Part# DA-4x4b
5/07
601 Heron Drive
Logan Township, NJ 08085
Phone: [phone] Fax: [phone]
http://www.radiosystems.com