TA6300 6 Channel Power Amplifier
2
SECTION 1
Introduction
The SMART modelTA6300 is a professional six-
channelamplifier featuringDC protection, quick
interconnectwith SMART companionproducts,
softclip speaker protectionand massiveheatsink
extrusionswith internalD.C.fan assistto make
sureyour amplifier stays cool evenwhen the
music is hot. TA6300 delivers 200 watts per
channel into 8 ohms on five channels simulta-
neous with 400 watts into 4 ohms on the sixth
(subwoofer)channel.
Circuit Description
Toassure absolutelong-term reliability, the
output section of each channel incorporates
multipleMotorola PowerTransistors,which
providethree timesthe amplifiers ratedpower in
watts of dissipation per channel. The output
stageis arranged ina fully complementary
formatfor classAB/2operation. The bias current
isevenly distributed amongall outputdevices.
Biasthermal compensation isaccomplished by
thermallymating abipolar semiconductor
junctionto the heat-producingoutput device.
Triple diffused highpower drivertransistorsare
employed along with high speed, high voltage
siliconannular devices forthe pre-driver and
inverterstages. Utilization ofthese components
provide the required separation of FT break
pointsfor absolutestability. Fully complemen-
tarydrive and loadingis utilized throughout.
Only 20dB of negative feedback is used to
reduceforward transferdistortion tominimum
levels. VItype energylimiters are incorporated
forshort circuitprotectionof theamplifier. Due
tothe unusually large safe operating areaof
outputstage, the limitersdo notactuate until
drivinga forty-five degreereactive load of under
2ohms at full power.
Construction
The amplifiers aredesigned on anall-modular
conceptpermitting rigorouspre-assembly mod-
uletesting andmaximum service accessibility.
Eachfunctional module isfully tested before
finalassembly. Although components of the
highestquality are usedthroughout, each ampli-
fieris burned in,prior toshipment, at theworst
caseoperating point toeliminate anypossibility
ofcomponent malfunction. All chassiscompo-
nentsare precision machinedfrom high quality
aluminum and 16-gauge sheet steel stock. The
entirepackage concept isdirected toward
maximumefficiency ofspace and structure,
accountingfor the compact size and light
weight.
SECTION 2
Installation
AllSMART amplifiers aredesigned for mounting
in a standard 19-inch equipment rack, or many
of the 19-inch rack type portable cases avail-
able. TheTA6300 require 7 inches of vertical
panel space, with 15" inches required behind
the panel. Total depth including the handles is
16-3/8" inches. Front panels are machined from
solidaluminum stock, witha blackpowdercoat
finishand sturdy rackmount handles.
Placementof theamplifier isnot criticalfor
normaloperation, providedsufficientairflow is
allowed to reach the heatsink array. If the unit is
to be placed on a shelf, or a similar unenclosed
area,allow four inches of clearance behindthe
fanair intake topermit airflowthrough the array.
Ifthe amplifier isto be mounted inan equipment
rackor cabinet withheat producing equipment,
besure that environmentaloperating tempera-
tures do not exceed 55 degrees C (131F).
Should overheating occur because of inad-
equateventilation, thetemperature protection
circuitrywillautomaticallyprotect theamplifier.
Whena safe operatingtemperature isrestored,
theamplifier willreturnto normaloperation.
