MTX Thunder4250D User manual

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i

CONGRATULATIONS
on your purchase of a new MTX
Thunder Amplifier! MTX has long
been the industry leader in mobile
enclosures and speakers, and we
have reached new heights with the
development of the new MTX Thunder
amplifiers. You couldn’t have chosen
a more reliable, powerful, or better
performing amplifier - In fact, we
back up every Thunder amplifier with
a three-year warranty if installed by
an authorized MTX retailer (see the
warranty statement on page 34).
Your new MTX Thunder amplifier was
designed, built and thoroughly tested at our
state-of-the-art electronics manufacturing
facility in Phoenix, Arizona. We manufacture
every amplifier using the latest intelligent
Surface Mount Technology. Some of the
advantages of the new design are its signifi-
cant improvements to the amplifier’s electri-
cal and mechanical properties. ISMT
devices feature substantially shorter internal
and external lead lengths. This reduces stray
capacitance and inductance, which results
in cleaner and more accurate musical repro-
duction with significantly less noise interfer-
ence. The ISMT mounter produces amplifier
boards with smaller and lighter components,
which are more resistant to vibrations inher-
ent in the automotive environment.
Awordaboutpowerratings.It isimportantforyou
to knowhowtheystack up.MTXhaschosenthe
mosthonest,mostconservativeway to rate our
amps.Weshowyouthe RMSpower,at 12.5volts,
anddynamicpowerat 14.4volts.However,we go
aboveand beyondthe call of duty.We test each
amplifier.Thetechnicianrecordsthe “actual”
power output, and recordsthis numberon your
Certified PerformanceCertificate.The amplifier
must meet or exceed the rated specification
beforewe’ll shipit. Noquestions.Noexceptions.
We want to ensure you get continuous
high performance from your MTX Thunder
amplifier, so we recommend that you
have it professionally installed by your
authorized MTX dealer.
HOWTO USETHIS MANUAL
If you are installing this amplifier yourself, we
recommend that you read the manual cover-
to-cover before you install it. Familiarize
yourself with the features and details on the
input and output panels. Make sure you have
all the equipment you need. Sample installa-
tion diagrams may be found on our website:
WWW.MTXAUDIO.COM
If you have any questions, write or call us at:
MTX
4545E.BaselineRd.
Phoenix,AZ85040
l-602-438-4545
P I-800~CALL-MTX
technicalQmtxaudio.com
www.mtxaudio.com
Registeryourwarrantyonline

Features
l
Intelligent Surface Mount Technology
l
Patented PWM MOSFETSwitching Power Supply (#5,598,325)
l
Adaptive Class DTechnology
l High Powered Transformer
l
High Powered stacked inductor
l Pure N-Channel Design
l
Doubles power into 2 ohms
l
Real lime Computerized Protection Circuit
l
Color-codedwire harnessfor speaker-levelinput installation onThunder4250Dand65000
l
Smart-EngageTMautoturn onfor easyintegrationwith factory headunitsThunder4250Dand6500D
l
Acoustically Seamless Turn-on/Turn-off (i.e. no noise)
l
Variable frequency low-pass crossover, 40Hzto 200Hz.24dB/octave low pass
l
Defeatable compression circuit included on Thunder6500D and Thunder810000
l
Continuously adjustable and defeatable Bass EQenhancement circuitry, centered at 40Hz
l Low level inputs
l
EBC- External Bass Control Port with an additional 3dB of gain when used, and 23dB attenuation
l Adjustable input sensitivity
l
Buffered RCAOutputs for daisy-chaining additional bass amplifiers
l
Nickel-plated, heavy duty terminal block type connectors
l
Unique rubber Insulated Iso-FeettM
Smecifications
THUNDER4250D THUNDER81000D
RMSPowermeasuredat 12.5VoltsDC:
125Wattsx 1into a4Ohmloadwith lessthan 1%ThdrN
250Wattsx I into a 2Ohmloadwith lessthan 1%ThdtN
DynamicPowermeasuredat 14.4VoltsDC
200Wattsx 1into a4 Ohmload
350Wattsx 1into a 2Ohmload
S~goalto NoiseRatio: >lOOdBA-Welghted
DampingFactor:,200
FrequencyResponse:ZOHz-200Hz
MaximumInput: avrms
ThunderE(1:VariableBassBoostIO-lad61centeredat 40Hz
Crossover:Variable4OHzto 200Hz.24dBioctavelow pass
Dimensions:7” x 915” x2” (17.8cmx 24.&m x 5.lcm)
9.9’ x 9.75”x 2.1”(23.6cmx 24&m x 5.3cm)IncludinglsoFe@
RMSPowermeasuredat 12.5VoltsDC:
500Wattsx I into a4 Ohmloadwith lessthan2%ThdtN
1000Wattsx I into a2Ohmloadwith lessthan 2%ThdtN
OynamfcPowermeasuredat 14.4VoltsDC
a50Wattsx I into a4 Ohmload
1500Wattsx 1into a2 Ohmload
Signalto NoiseRatio:tlOOdBA-Welghted
DampIngFactor:>I00
FrequencyResponse:ZOHz-200Hz
MaxImumInput: BVrms
ThunderE(1:VariableBassBoostIO-l8dB)centeredat4OHz
Crossover:Variable40Hzto 2WHz.24dBioctavelow pass
0imenslons:lM” x9.75”x 2”.(40.lcmx 24.8cmx 5.lcm)
17.Kx 9.W x 2.1’ I452cmx 24.8cmx5.3cm)IncludingIsoFeerM
RecommendedFuse= 150A
THUNDER6500D
RMSPowermeasuredat 12.5VoltsDC:
250Wattsx I into a4Ohmloadwith lessthan 1%ThdtN
500Wattsx 1mtoa2Ohmloadwith lessthan I% ThdtN
DynamicPowermeasuredat 14.4VoltsDC
450Wattsx I mtoa 4Ohmload
775Wattsx I mtoa 2Ohmload
Signalto NoiseRatio:>lOOdBA-Welghted
DampingFactor:,200
FrequencyResponse:ZOHz-200Hz
MaximumInput: BVrms
ThunderEtI VariableBassBoostIO-18dBlcenteredat40Hz
Crossover:Variable40Hzto 2WHz.24dBloctavelow pass
Dimensions:11.5”x9.75”x 2” (29.2cmx 24.8cmx 5.lcm)
13.9”x 9.75”x 2.1”(36.6cmx 24.8cmx 5.3cm)IncludinglsoFeeCM

1. Gain Controls -These controls are used to match the input sensitivity of the amplifier to the particular
source unit that you are using. The controls are factory set to IVrms.
2. Thunder EQ- This equalization circuit is used to enhance the low frequency response of the vehicle’s
interior. With up to 18dB of boost and centered at 40Hz,the Bass EQcan be adjusted to meet your own
personal taste.
3.Frequency Control -This control is continuously adjustable from 40Hzthrough 200Hzat 24dBper octave.
Factory setting is at 40Hz.
4. RCAInput Jacks - RCAtype input jacks for use with source units that have RCAor Line Level Outputs.
A source unit with a minimum output level of 200mVis required for proper operation. However, this input
will accept levels upto 8Vrms.
5. EBC2- The EBC,or Electronic Bass Control, allows a remote bass control to be adjusted from the dri-
ver’s seat, Ifthe optional EBCis installed, the bass level will be ableto be adjusted to overcome noise and
other interference. With EBC2 multiple amplifiers can be controlled.
6. RCA-OutputJacks-These RCAoutputs allow for a signal to be sent to other amplifiers in a daisy-chain
configuration. The RCAoutputs also allow for multiple bass amplifiers to be level controlled using one EBC.
7. Speaker level Inputs - This input will allow the Thunder425Dand 6500Dto operate from source units
with speaker-level outputs. Output speaker leads from the source unit should be tied directly to the wire
harness provided with the amplifier.
Wire harness color codes:
Grey/ Black = Source units right negative (-) White / Black = Source units left negative (-)
Solid Grey= Source units right positive (t) Solid White = Source units left positive (t)
With the Smart-EngageTMauto-turn circuit, a remote turn-on wire is not necessary when connecting the
speaker-level input wire harness to a high powered source unit. The amplifier will automatically turn on
when music is received.
8. Compression Circuit - This new circuit, found on the Thunder6500D and ThunderSlOOOD,
prevents the amplifier from going into clipping, even at high SPLlevels. The compression circuit allows the
listener to playthe amplifier at high volume levels, yet protects the speakers against the potential damage
that can occur during dynamic musical passages. The circuit is switchable on/off, for those SPLcompeti-
tors who runtheir amplifiers into clipping on purpose.Warning; Damageto speakers may occur when the
compression circuit is in the off position.

1nm.d Panel Lavout

1.Fuses-Forconvenience,allamplifiersutilizeATCtypefuses. Forcontinuedprotectionintheeventthatafuseblows,
replacethefuseonlywiththe samevalue.
Caution- The powerfuses on the amp are for protectingthe amp against overdrive. To protect the vehicle’s
electricalsystem,anadditionalfuseis requiredwithin 18”ofthe batteryonthe 12Vtcable.
Thunder42500- 20Ax 2
Thunder65OOD-25Ax3
Thunder81000D- 150Amps (not supplied)
2.PowerTerminal-This terminalis wherethe powersourceofthe vehicle is connected. The12Vt mustbecon-
necteddirectly to the positivebatterypost. It is highlyrecommendedthat youplace anadditionalfusewithin 18”
of the batteryconnection, Besureto usethe correct gaugeof powercable! If wire of insufficient sizeis used,
therewill beavoltagedropandthe ampwill starve,causingpoorperformance. In anextremecase,the ampmay
shutdownduetothe low batteryvoltageprotectionfeature. Theterminalclosesttothe fuse(s)iswherethe power
cablewith connectorshouldbeinstalled. Besureto makeyourconnectioncleanto avoidanyshortingto the other
terminals. Alwaysdoublecheckall ofthe connectionsfor anydiscrepancies.08
Thunder42500- 6-8 Gauge
Thunder6500D- 4-6 Gauge
Thunder81000D- l/O Gaugeonly
3.RemoteTerminal-Thisisthewirethatturns theamplifieronandoff.Thisterminalconnectstotheampturn-onlead
orthe powerantennaleadcomingfromthe sourceunit. Ifthe sourceunitdoesn’thaveoneofthesewires,youcan
eitherrunawire to the batterywith a switch or useanignitioncontrolledwire to powerupthe amp. Ifyou usethe
ignition controlledwire, be awarethat the amplifierwill be on, as long as the car is on.When usingthe Smart
Engage” feature,ahighpoweredradio,andspeakerlevelinputsit is notnecessarytoconnecttheRemoteTerminal.
4.GroundTerminal-The groundterminalconnectsthe amplifierto thevehicleground. Besureto usethe samesize
wire gaugeorlargerasthet12Vconnection.A stronggroundpointisveryimportant.A littlescrewthroughthebody
isnotacceptable.Thecableshouldbeasshortaspossibleandconnectedtothechassisofthevehicle. Thecontact
pointshouldbefree of paintanddebrisfor bestresults. All precautionsfor the 12Vt connectionapplyto this con-
nectionaswell.
5.PowerLED(topoiheatsink)-A lightedLEDindicatesthat power hasbeenappliedto the amplifier. t12V fromthe
batteryto the tBAll terminal (#lo) and t12V from a switched ignition or remote lead from a head unit. An
unlightedLEDindicates power has beenremovedorthe amplifierhas overheated. Inthe case ofthe overheat
condition,the amplifierwill turn back on after it cools down. P
6. 4 Term Block- The t and - terminals connect the speaker to the amplifier. 2 ohm minimum
impedance is allowed.

Outnut Panel Lavout

Adiustina the? Gain
1. Turnthe gain control on the amplifier all the way down.
2. Turn up the volume control on the source unit to
approximately 3/4 of maximum.
3. Adjustthe gain control on the amplifier until audible distor-
tion occurs.
4. Adjust the gain control down until audible distortion dis-
appears.
5. The amplifier is now calibrated to the output of the
source unit.
Definitions of
Common Terms
Thefollowing list of terms with their definitions is offered as
help in understanding the set-up and operation of your
amplifier.
1. Crossoverfxover) - an electrical filter with hrgh-pass or
low-pass characteristics that divides the frequency range
into playablebandsfor certain speakers. Subwoofers,mid-
bass,midrangeandtweeters are all designedto playdiffer-
ent frequencies and should do so to avoid damage. The
xover point is where the playable frequencies cross from
onespeakerto the next at -3dBbelow reference level.
2.Full-range - refersto signalswhich coverthe entire audio
frequency spanfrom 20Hzto 20kHz.
3. High-pass - simply put, this blocks lower frequencies
which damage smaller speakers, and passes the higher
frequencies for smaller speakers like the midrange and
tweeter.
4.Low-pass-You got it,this is the inverse of a high-pass. It
blocks higher frequencies and passes the playable lower
frequencies to the larger speakers,like subwoofers.
Tvmical Sneaker
Wirinq
Confiuurations
Mono Amplifier
Impedance Requirement
2 ohm minimum
5. Impedance - the resistance to the flow of current in an
alternating current circuit (such as with music). Linelevel
circuits are typically a high impedanceof severalthousand
ohms,while speaker level circuits are usually a low imped-
ance of a few ohms.
6. Linelevel - ThetYpeof signal produced atthe outputs of
tape decks, CD tuners, preamplifiers, etc., with a typical
value of avolt or less in a high impedancecircuit.
7. Speaker level - Thetype of output that is meantto drive
speaker= These signals are sometimes called high level
andare usuallyconnected bytwo conductor speakerwires.
8. Signal - The signal of an audio system is what is heard
from the speakers. These signals may be high pass, low
passor full-range.
We don’t have enough space for Electronics 101,so if you
have a good, bad or amusingquestion,please call us TOLL
FREEat 800-CALL-MTX!(800-225-5689)

Troubleshooting Guide
Readthisif youwannabeado-it-yourselfer--orgiveusacallat I-BOO-CALLMTX
&!A!&
NoLEDindication
LEDon,nooutput
Outputdistorted
Balancereversed
Somebalancereversed
Bassisboomy
Bassisweak
Not12Vatremoteconnection
Not12VatPowerconnection
Insufficientgroundconnection
Blownpowerfuse
Volumeonheadunitoff
Speakerconnectionsnotmade
Gaincontrolonamplifieroff
Signalprocessingunitsoff
Allspeakersblown
Headunitvolumesettoohigh
Amplifiergainsettoo high
SpeakerswiredLt Rreversed
RCAinputsreversed
SomeSpeakerswiredLt R
reversed
SomeRCAinputsreversed
ThunderEQtoohigh
ThunderEQtoolow
Speakerswiredout
ofphase
NotusingMTXwoofers
Excessiveoutputlevels
Amplifierdefective
&&jLo
Supplyt12Vtoterminal
Supplyt12Vtoterminal
Verifygroundconnection
Replacefuse
Increasevolumeonheadunit
Makespeakerconnections
Turnupgain
Applypowertosignalprocessor
Replacespeakers
Lowerheadunitvolume
Loweramplifiergain
Wirespeakerswithcorrectorientation
ReverseRCAinputs
Wirespeakerswithcorrectorientation
ReverseappropriateRCAinputs
Lowersetting
Raisesetting
Wirewithcorrectphase
BuyMTXwoofers
Lowervolume
Returnforservice
Blowingfuses

Warranty
All MTXThunder Amplifiers purchasedinthe USAare guaranteed against defects in
material andworkmanship for a periodof three years from the date purchased bythe
end user, if the amplifier is installed by an authorized MTX dealer (one year, if
installed bythe consumer).Thiswarranty is limited to the original retail purchaser of
product. MTX disclaims any liability for the other incurred damages resulting from
product defects. Any expenses incurred in the removal and reinstallation of
amplifiers are not coveredbythis warranty. MTX’stotal liability will not exceed the
purchase price ofthe amplifier. This warranty is valid only inthe USA.
To ensure efficiency and full benefit on any warranty claim during the warranty
period stated above, MTX requests the return of the warranty registration card,
completed in full immediately following purchase. Proof of purchase must be
provided attime ofwarranty claim. If there is no proof of purchase provided with the
warranty claim, MTX reserves the right not to honor the warranty set forth above.
Therefore, labor andparts may be charged to you.
This warranty doesnot apply to product exterior and cosmetics. Misuse, abnormal
service or handling,improper alterations or modifications in design or construction
void this warranty.
No sales personnel of the seller, or any other person is authorized to make any
warranties other than those described above or to extend the duration of any
warranties on behalf of MTX beyondthe time period described above.
ForWarranty Inquiries, please call:
l-800-225-5689
l-602-438-4545
MTX
4545E.Baseline Rd.
Phoenix,Arizona 85040
RegisterWarranty On-line:
www.mtxaudio.com

Please fold and seal with tape
WARRANTYREGlSTRATlON&CUSTOMERSURVEY
NAME
PHONE
ADDRESS AGE
OCCUPATION
DEALERNAME
MTXMODELNO.
DATEPURCHASED
VEHICLETYPE
CITY
INSTALLEDBY
YEAR MAKE MODEL
1. WASTHISUNIT CI Purchasedforpersonaluse 0 Receivedasagift
2. HOWDIDYOUFIRSTLEARNOFMTX?
0 Dealer D Radio 0 TV m Newspaper 0 Catalog
m Friend/Family0 Storedisplay
CI Magazine(Circlethemagazine) MotorTrend CarandTrack RollingStone Lowrider
Truckin’ AutosoundandSecurity CarSound CarAudioandElectronics CarStereoReview
Q Other
3. ISTHIS: D Yourfirstcarstereo CI Replacement/Upgrade
4. WHATWASTHEMAINREASONYOUSELECTEDTHISMTXPRODUCT?
Ll Dealerrecommendation
B MTXName/reputationa Friend/familyrecommendation
a ProductAppeal U Sound 0 Price D Other
5. WHATARETHREETHINGSYOULIKEMOSTABOUTTHISMTXPRODUCT?
It Styling It SoundQuality U Powerhandling m BassReproduction
D Durability 0 InstallationFlexibility
6. HOWSATISFIEDAREYOUWITHTHISPRODUCT?
13VerySatisfied a Satisfied c3Neutral CIINotSatisfied
7. WHEREDOYOUBUYYOURTAPESANDCD’S?
COMMENTS

TiiMW#f~E~~~OOOD
Amplifier Input Connections
AMPLIFIER
CAR STEREO
(SOURCE UNIT)
Remote/Power Antenna
Turn-On Wire
REQUIRED INSTALLATION
TOOLS:
Power Drill Utility Knife
Adjustible Wrench l Crimpers l Screw Driver
For installation options go to www.mtxauciio.com

r
r,,~~~E~S10000
Amplifier Output Connections
1
AMPLIFIER
Connect to Car Stereo
Remote/Power Antenna
Turn-On Wire
Ground To Metal
Disconnect
Battery Negative (-) Cable
Prior to Installing Amplifier
Power: l/O AWG. Ground: l/O AWG.
CAUTION: This amplifier may draw in excess of 150 Amps of current.
Upgrading the vehicle’s factory battery and alternator is required.
(For specific details, contact your local authorized MTX dealer, or call l-800~CALL-MTX.)
Remove Paint J
from Metal
For installation options go to mtxaudio.com