Lexicon
NT Series
Amplifiers
User Guide
Models 212, 312, 412,
225 and 501
Unpacking and Inspection
After unpacking the amplifier, save all packing materials in case you ever need to ship the unit. Thoroughly inspect
the amplifier and packing materials for signs of damage. Report any shipment damage to the carrier at once; report
equipment malfunction to your dealer.
Precautions
Save these instructions for later use.
Follow all instructions and warnings marked on the unit.
Always use with the correct line voltage. Refer to the manufacturer's operating instructions for power requirements. Be advised that different
operating voltages may require the use of a different line cord and/or attachment plug.
Do not install the unit in an unventilated rack, or directly above heat producing equipment such as power amplifiers. Observe the maximum
ambient operating temperature listed in the product specification.
Slots and openings on the case are provided for ventilation; to ensure reliable operation and prevent it from overheating, these openings must
not be blocked or covered. Never push objects of any kind through any of the ventilation slots. Never spill a liquid of any kind on the unit.
This product is equipped with a 3-wire grounding type plug. This is a safety feature and should not be defeated.
To prevent shock or fire hazard, do not expose the unit to rain or moisture, or operate it where it will be exposed to water.
Do not attempt to operate the unit if it has been dropped, damaged, exposed to liquids, or if it exhibits a distinct change in performance indicating
the need for service.
This unit should only be opened by qualified service personnel. Removing covers will expose you to hazardous voltages.
This triangle, which appears on your
component, alerts you to the presence of uninsulated, dangerous voltage inside the enclosure... voltage
that may be sufficient to constitute a
risk of shock.
CAUTION
RISK OF ELECTRIC SHOCK
DO NOT OPEN
This triangle, which appears on your
component, alerts you to important
operating and maintenance instructions in this accompanying literature.
Acknowledgements
The Lexicon NT Series amplifiers are custom manufactured for Lexicon by Bryston Ltd. of Ontario, Canada.
The CP and DC Series are manufactured under license from Dolby Laboratories Licensing Corporation. Additionally licensed under one or
more of the following patents: U.S. numbers 3,632,886, 3,746,792 and 3,959,590; Canadian numbers 1,004,603 and 1,037,877. "Dolby" and
the double-D symbol are trademarks of Dolby Laboratories Licensing Corporation.
The NT Series amplifiers are manufactured under license from LucasArts Entertainment Company.
"THX" and "Home THX Cinema" are trademarks of LucasArts Entertainment Company.
Copyright 1995 Lexicon, Inc.
All Rights Reserved.
Lexicon Part # 070-11325
Lexicon Inc.
3 Oak Park
Bedford, MA 01730
Tel 781-280-0390
Fax 781-280-0490
www.lexicon.com
Dansk
Vigtig information om sikkerhed
Gem denne vejledning til senere brug.
Følg alle anvisninger og advarsler på apparatet.
Apparatet skal altid tilsluttes den korrekte spænding. Der henvises til
brugsanvisningen, der indeholder specifikationer for strømforsyning. Der
gøres opmærksom på, at ved varierende driftsspændinger kan det blive
nødvendigt at bruge andre lednings- og/eller stiktyper.
Apparatet må ikke monteres i et kabinet uden ventilation eller lige over
andet udstyr, der udvikler varme, f.eks. forstærkere. Den maksimale
omgivelsestemperatur ved drift, der står opført i specifikationerne, skal
overholdes.
Der er ventilationsåbninger i kabinettet. For at sikre apparatets drift og
hindre overophedning må disse åbninger ikke blokeres eller tildækkes. Stik
aldrig noget ind igennem ventilationsåbningerne, og pas på aldrig at spilde
nogen form for væske på apparatet.
Dette apparat er forsynet med et stik med jordforbindelse. Denne
sikkerhedsforanstaltning må aldrig omgås.
Apparatet må ikke udsættes for regn eller fugt og må ikke bruges i
nærheden af vand for at undgå risiko for elektrisk stød og brand.
Apparatet må aldrig bruges, hvis det er blevet stødt, beskadiget eller vådt,
eller hvis ændringer i ydelsen tyder på, at det trænger til eftersyn.
Dette apparat må kun åbnes af fagfolk. Hvis dækslet tages af, udsættes
man for livsfarlig højspænding.
Denne mærkat på komponenten advarer om uisoleret, farlig spænding
i apparatet ... høj nok til at give elektrisk stød.
Denne mærkat på komponenten advarer om vigtig drifts- og
vedligeholdsinformation i den tilhørende litteratur.
Suomi
Tärkeitä turvallisuusohjeita
Säilytä nämä ohjeet tulevaa käyttöä varten.
Seuraa kaikkia yksikköön merkittyjä ohjeita ja varoituksia.
Käytä aina oikeaa verkkojännitettä. Tehovaatimukset selviävät valmistajan
käyttöohjeista. Huomaa, että eri käyttöjännitteet saattavat vaatia
toisenlaisen verkkojohdon ja/tai -pistokkeen käytön.
Älä asenna yksikköä telineeseen jossa ei ole tuuletusta, tai välittömästi
lämpöä tuottavien laitteiden, esim. tehovahvistimien, yläpuolelle. Ympäristön
lämpötila käytössä ei saa ylittää tuotespesifikaation maksimilämpötilaa.
Kotelo on varustettu tuuletusreiillä ja -aukoilla. Luotettavan toiminnan
varmistamiseksi ja ylilämpenemisen välttämiseksi näitä aukkoja ei saa
sulkea tai peittää. Mitään esineitä ei saa työntää tuuletusaukkoihin. Mitään
nesteitä ei saa kaataa yksikköön.
Tuote on varustettu 3-johtimisella maadoitetulla verkkopistokkeella. Tämä
on turvallisuustoiminne eikä sitä saa poistaa.
Sähköiskun ja palovaaran välttämiseksi yksikkö ei saa olla sateessa tai
kosteassa, eikä sitä saa käyttää märässä ympäristössä.
Älä käytä yksikköä jos se on pudonnut, vaurioitunut, kostunut, tai jos sen
suorituskyky on huomattavasti muuttunut, mikä vaatii huoltoa.
Yksikön saa avata vain laitteeseen perehtynyt huoltohenkilö. Kansien
poisto altistaa sinut vaarallisille jännitteille.
Tämä kolmio, joka esiintyy komponentissasi, varoittaa sinua
eristämättömän vaarallisen jännitteen esiintymisestä yksikön sisällä.
Tämä jännite saattaa olla riittävän korkea aiheuttamaan
sähköiskuvaaran.
Tämä kolmio, joka esiintyy komponentissasi, kertoo sinulle, että
tässä tuotedokumentoinnissa esiintyy tärkeitä käyttö- ja ylläpitoohjeita.
Norsk
Viktig informasjon om sikkerhet
Ta vare på denne veiledningen for senere bruk.
Følg alle anvisningene og advarslene som er angitt på apparatet.
Apparatet skal alltid anvendes med korrekt spenning. Produktbeskrivelsen
inneholder spesifikasjoner for strømkrav. Vær oppmerksom på at det ved
ulike driftsspenninger kan være nødvendig å bruke en annen ledning- og/
eller støpseltype.
Apparatet skal ikke monteres i skap uten ventilasjon, eller direkte over
varmeproduserende utstyr, som for eksempel kraftforsterkere. Den
maksimale romtemperaturen som står oppgitt i produktbeskrivelsen, skal
overholdes.
Apparatet er utstyrt med ventilasjonsåpninger. For at apparatet skal være
pålitelig i bruk og ikke overopphetes, må disse åpningene ikke blokkeres
eller tildekkes. Stikk aldri noe inn i ventilasjonsåpningene, og pass på at det
aldri søles noen form for væske på apparatet.
Dette apparatet er utstyrt med et jordet støpsel. Dette er en
sikkerhetsforanstaltning som ikke må forandres.
Unngå brannfare og elektrisk støt ved å sørge for at apparatet ikke utsettes
for regn eller fuktighet og ikke anvendes i nærheten av vann.
Apparatet skal ikke brukes hvis det har blitt utsatt for støt, er skadet eller blitt
vått, eller hvis endringer i ytelsen tyder på at det trenger service.
Dette apparatet skal kun åpnes av fagfolk. Hvis dekselet fjernes, utsettes
man for livsfarlig høyspenning.
Komponenten er merket med denne trekanten, som er en advarsel
om at det finnes uisolert, farlig spenning inne i kabinettet ... høy nok
til å utgjøre en fare for elektrisk støt.
Svenska
Viktiga säkerhetsföreskrifter
Spara dessa föreskrifter för framtida bruk.
Följ alla anvisningar och varningar som anges på enheten.
Använd alltid rätt nätspänning. Se tillverkarens bruksanvisningar för infor-
mation om effektkrav. Märkväl, att andra matningsspänningar eventuellt
kräver att en annan typs nätsladd och/eller kontakt används.
Installera inte enheten i ett oventilerat stativ, eller direkt ovanför utrustningar
som avger värme, t ex effektförstärkare. Se till att omgivningens temperatur
vid drift inte överskrider det angivna värdet i produktspecifikationen.
Behållaren är försedd med hål och öppningar för ventilering. För att
garantera tillförlitlig funktion och förhindra överhettning får dessa öppningar
inte blockeras eller täckas. Inga föremål får skuffas in genom ventilationshålen.
Inga vätskor får spillas på enheten.
Produkten är försedd med en jordad 3-trådskontakt. Detta är en
säkerhetsfunktion som inte får tas ur bruk.
För att undvika elstöt eller brandfara får enheten inte utsättas för regn eller
fukt, eller användas på ställen där den blir våt.
Använd inte enheten om den har fallit i golvet, skadats, blivit våt, eller om
dess prestanda förändrats märkbart, vilket kräver service.
Enheten får öppnas endast av behörig servicepersonal. Farliga spänningar
blir tillgängliga när locken tas bort.
Denna triangel, som visas på din komponent, varnar dig om en
oisolerad farlig spänning inne i enheten. Denna spänning är eventuellt
så hög att fara för elstöt föreligger.
Komponenten er merket med denne trekanten, som betyr at den
tilhørende litteraturen inneholder viktige opplysninger om drift og
vedlikehold.
Denna triangel, som visas på din komponent, anger att viktiga
bruksanvisningar och serviceanvisningar ingår i dokumentationen i
fråga.
Wichtige Sicherheitsanweisungen
Deutsch
Heben Sie sich diese Sicherheitsanweisungen auch für später auf.
Befolgen Sie alle auf der Vorrichtung stehenden Anweisungen und Warnungen.
Immer nur mit der richtigen Spannung verwenden! Die Gebrauchsanweisungen
des Herstellers informieren Sie über die elektrischen Anforderungen.
Vergessen Sie nicht daß bei verschiedenen Betriebsspannungen ggf. auch
verschiedene Leitungskabel und/oder Verbindungsstecker zu verwenden
sind.
Stellen Sie die Vorrichtung nicht in ein unbelüftetes Gestell oder unmittelbar
über wärmeerzeugende Geräte wie z.B. Tonverstärker. Halten Sie die in den
Produktspezifikationen angegebene maximale Umgebungstemperatur bei
Betrieb ein.
Schlitze und Öffnungen im Gehäuse dienen der Belüfung; um verläßlichen
Betrieb sicherzustellen und Überheizen zu vermeiden dürfen diese Öffnungen
nich verstopft oder abgedeckt werden. Stecken Sie nie irgend einen
Gegenstand durch die Belüftungsschlitze. Vergießen Sie keine Flüssigkeiten
auf den Apparat.
Dieses Produkt is mit einem 3-drahtigen Erdungsstecker ausgerüstet. Diese
Sicherheitsmaßnahme darf nicht unwirksam gemacht werden.
Um elektrischen Schlag oder Feuer zu vermeiden, setzen Sie den Apparat
weder Regen noch Feuchtigkeit aus und betreiben Sie ihn nicht dort wo
Wasser eindringen könnte.
Versuchen Sie nicht den Apparat zu betreiben falls er fallen gelassen,
beschädigt, oder Flüssigkeiten ausgesetzt wurde, oder falls sich seine
Arbeitsweise derart ändert daß daraus ein Bedarf nach Raparatur zu schließen
ist.
Dieser Apparat sollte nur von qualifizierten Fachleuten geöffnet werden. Das
Abnehmen von Abdeckungen setzt Sie gefährlichen Spannungen aus.
Español
Instrucciones importantes de seguridad
Guarde esta instrucciones para uso posterior.
Utilice siempre el voltaje correcto. Diríjase a las instrucciones de operación
del fabricante para obtener las especificaciones de potencia. Esté al tanto
de que voltajes de operación distintos requieren el uso de cables y/o
enchufes distintos.
No instale esta unidad en un estante sin ventilación, ni tampoco directamente
encima de equipos que generen calor tales como amplificadores de potencia.
Fíjese en las temperaturas ambientales máximas de operación que se
mencionan en las especificaciones del producto.
Las aperturas y ranuras del chasis sirven para proveer la ventilación
necesaria para operar la unidad con seguridad y para prevenir
sobrecalentamiento, y por lo tanto no pueden ser obstruidas o cubiertas. No
introduzca objetos de ningún tipo a través de las ranuras de ventilación, y
nunca deje caer ningún líquido sobre la unidad.
Este producto está equipado con un enchufe de 3 clavijas con conexión a
tierra. Éste es un elemento de seguridad que no debe ser eliminado.
Para prevenir descargas eléctricas o incendios, mantenga la unidad alejada
de la lluvia, humedad o cualquier lugar en el que pueda entrar en contacto
con agua.
No trate de hacer funcionar la unidad si se ha caído, está dañada, ha entrado
en contacto con líquidos, o si nota cualquier cambio brusco en su
funcionamiento que indique la necesidad de hacerle un servicio de
mantenimiento.
Esta unidad deberá ser abierta únicamente por personal calificado. Si usted
quita las coberturas se expondrá a voltajes peligrosos.
Dieses Dreieck auf Ihrem Apparat warnt Sie vor nicht-isolierter,
gefährlicher Spannung im Gehäuse ... stark genug um eine
Berührungsgefahr darzustellen.
Dieses Dreieck auf Ihrem Apparat bedeutet daß wichtige Betriebsund Wartungsanweisungen in der mitgelieferten Dokumentation zu
finden sind.
Français
Instructions de Sûreté Importantes
Gardez ces instructions pour réference future.
Observez toutes les instructions et tous les avertissements marqués sur
l’appareil.
Branchez uniquements sur un réseau de tension indiquée. Consultez le
manuel d’instruction du fabriquant pour les spécifications de courant.
N’oubliez pas que différentes tensions peuvent nécessiter l’utilisation de
cables et/ou de fiches de connexion différents.
N’installez pas l’appareil en un compartiment non-aéré ou directement audessus d’équipements générateurs de chaleur, tels qu’amplificateurs de
courants, etc. Ne dépassez pas la température ambiante maximale de
fonctionnement indiquée dans les spécifications du produit.
Des fentes et ouvertures sont prévues dans le boîtier pour l’aération; Pour
assurer le bon fonctionnement et pour prévenir l’échauffement, ces ouvertures
ne doivent pas être couvertes ou bloquées. N’insérez pas d’objets dans les
fentes d’aération. Empêchez tout liquide de se répandre sur l’appareil.
Ce produit est muni d’une fiche à trois fils pour la mise à terre. Ceci est une
mesure de sécurité et ne doit pas être contrariée.
Pour empêcher les chocs électriques et le danger d’incendie, évitez d’exposer
l’appareil à la pluie ou à l’humidité, et ne le mettez pas en marche en un
endroit où il serait exposé aux éclaboussures d’eau.
N’essayez pas de faire fonctionner l’appareil s’il est tombé à terre, a été
endommangé, exposé à un liquide, ou si vous observez des différences
nettes dans son fonctionnement, indiquant la nécessité de réparations.
Cet appareil ne doit être ouvert que par un personnel de service qualifié. En
enlevant les couvercles vous vous exposez à des tensions électriques
dangereuses.
Este triángulo que aparece en su componente le advierte sobre la
existencia dentro del chasis de voltajes peligrosos sin aislantes ...
voltajes que son lo suficientemente grandes como para causar
electrocución.
Este triángulo que aparece en su componente lo alerta sobre las
instrucciones de operación y mantenimiento importantes que están
en los materiales de lectura que se incluyen.
Italiano
Importanti norme di sicurezza
Conservare le presenti norme per l’utilizzo futuro.
Osservare tutte le istruzioni e le avvertenze apposte sull’unità.
Utilizzare esclusivamente con la tensione di rete corretta. Consultare le
istruzioni operative fornite dal fabbricante per i dati riguardanti la tensione e
l’assorbimento di corrente. Potrebbe essere necessario l’uso di cavi di rete
e/o di spine diverse a seconda della tensione utilizzata.
Non installare l’unità in uno scaffale privo di ventilazione oppure direttamente
sopra una fonte di calore, come, ad esempio, un amplificatore. Non superare
la temperatura ambientale massima di funzionamento riportata nei dati
tecnici del prodotto.
Le fessure e le altre aperture nella scatola servono alla ventilazione. Per un
funzionamento affidabile, e per evitare un eventuale surriscaldamento,
queste aperture non vanno ostruite o coperte in nessun modo. Evitare in tutti
i casi di inserire oggetti di qualsiasi genere attraverso le fessure di ventilazione.
Non versare mai del liquido di nessun tipo sull’unità.
Questo prodotto viene fornito con una spina a 3 fili con massa. Tale
dispositivo di sicurezza non va eliminato.
Per prevenire il pericolo di folgorazione e di incendio non esporre l’unità alla
pioggia o ad un’umidità eccessiva; evitare di adoperare l’unità dove potrebbe
entrare in contatto con acqua.
Evitare di adoperare l’unità se la stessa è stata urtata violentemente, se ha
subito un danno, se è stata esposta ad un liquido o in caso di un evidente
cambiamento delle prestazioni che indichi la necessità di un intervento di
assistenza tecnica.
Ogni intervento sull’unità va eseguito esclusivamente da personale qualificato.
La rimozione della copertura comporta l’esposizione al pericolo di
folgorazione.
Ce triangle, sur votre appareil vous avertit de la présence de tension
dangereuse, non-isolée à l’intérieur du boîtier...une tension suffisante
pour représenter un danger d’électrocution.
Ce triangle sur sur votre appareil vous invite de suivre d’importantes
instructions d’utilisation et d’entretien dans la documentation livrée
avec le produit.
Il presente triangolo impresso sul componente avverte della presenza
di tensioni pericolose non isolate all’interno della copertura... tali
tensioni rappresentano un pericolo di folgorazione
Il presente triangolo impresso sul componente avverte l’utente della
presenza nella documentazione allegata di importanti istruzioni relative
al funzionamento ed alla manutenzione.
Introduction
Overview .................................................................................... 1
Models 212 and 225.................................................................................. 2
Model 312 .................................................................................................. 2
Model 412 .................................................................................................. 3
Model 501 .................................................................................................. 3
Installation............................................................................................4
Mounting ................................................................................................... 4
Power Requirements................................................................................ 5
Audio Connections .................................................................................. 5
Ground Lift Switch .................................................................................. 5
Operation................................................................................... 6
Front Panel LEDs...................................................................................... 6
Remote Trigger ......................................................................................... 6
Bridged Operation ................................................................................... 7
Troubleshooting ....................................................................................... 7
Maintenance.............................................................................................. 7
Specifications ............................................................................ 8
Contents
Lexicon NT Series Amplifiers
Congratulations on your purchase of a Lexicon amplifier. Your amplifier has
been designed and manufactured for absolute linearity and stability. Utilizing
a unique Quad-Complementary output stage, the NT Series amplifers produce
less distortion than even Class A designs, with higher efficiency and better long
term reliability. A wide variety of input and output connections and configurations are accommodated, as well as unique features specific to complex multichannel audio systems.
The amplifiers are not “voiced” to “sound” a certain way. We believe an
amplifier’s goal is simple; to amplify the signal, accurately and cleanly, into any
load, without imparting any coloration or distortion. Indeed, the distortion
components of our amplifiers are near the limits of sophisticated test instruments. The amplifier’s sound can best be described as utterly neutral.
While the amplifier’s goal is simple, its job is not. Over 20 years of amplifier
research and design have resulted in products that perform flawlessly, year
after year after year. Sophisticated engineering, manufacturing, and testing are
combined with meticulous craftsmanship and pride. We believe that you will
come to pay our amplifer the highest compliment; you will forget about it! The
amplifier will quietly, cleanly and reliably perform its job. Enjoy the music,
enjoy the movies, forget about the equipment. Thank you for choosing Lexicon.
This manual is designed for installation of any of the five amplifiers models in
the Lexicon series: 212, 312, 412, 225 and 501. Whichever model you have
selected, we are sure that you will be pleased with its quality and performance.
Introduction
The 17" model is standard for all models in the
NT Series. A 19" rack mount version is available
in 120V configurations.
We have designed this manual to provide a brief overview of each amplifier, as
well as to provide the information necessary for safe installation and operation.
We trust that the time you invest in reviewing these brief instructions will be
rewarded by the best possible performance and longevity of your equipment.
1
Lexicon NT Series Amplifiers
Overview
Models 212 and 225
The 212 stereo amplifier consists of 2 amplifier modules, each with its own
power supply. The channels may be operated independently (1=left; 2=right)
for stereo at 120 watts/channel @ 8Ω, 200 watts @ 4Ω, or bridged (monaural)
to form a single 400 watt amplifier into 8Ω.
Model 312
The 225 stereo amplifier provides 250 watts/channel @ 8Ω, 400 watts @ 4Ω, or
it can be bridged (monaural) to form a single 800 watt amplifier into 8Ω.
The 312 power amplifier consists of 3 independent amplifier modules, each with
its own +55V power supply, and 4 custom power transistors for a total of 12
output devices.
Channels 1, 2 and 3 may be operated independently at 120 watts/channel @ 8Ω,
200 watts @ 4Ω. Channels 1 and 2 can be bridged (monaural) to form a single
400 watt channel into 8Ω with channel 3 providing an additional 120 watts @8Ω.
2
The 412 power amplifier consists of 4 independent amplifier modules, each with
its own +55V power supply, and 4 custom power transistors for a total of 16
output devices. The 412 can be configured to drive 2, 3 or 4 speakers: 4 channels
at 120 watts into 8Ω, or 2 channels at 120 watts plus 1 channel at 400 watts, or 2
channels at 400 watts. This provides complete flexibility in any present or future
audio or video system.
Lexicon NT Series Amplifiers
Model 412
With 4 discrete channels available, the 412 is an excellent choice to bi-amplify
your audio or video system, either actively using an electronic crossover, or
passively, using independent connectors for the high and low frequency
drivers.
The 501 power amplifier consists of 2 amplifier modules, each with its own +60V
power supply and 8 custom power transistors, for a total of 16, or 32 per stereo
pair. The 2 modules can be configured in either Series or Parallel* mode to form
a single mono power amplifier capable of up to 800 watts. The Series mode
connects the modules in a bridged configuration. The output voltage swing is
thus additive, and is appropriate for driving loads from 3-8Ω. Parallel mode
yields the voltage swing of a single amplifier module, but the current available
is additive, and is appropriate for driving loads from 1-3Ω.
Model 501
* As the impedance ranges describe nominal, not minimum, impedance, it is almost never advisable
to use Parallel mode for direct connection to a speaker. Parallel mode is generally only useful when
abnormally low impedances (1Ω or less) are created from parallel wiring of multiple speakers.
3
Lexicon NT Series Amplifiers
Installation
Mounting
Selecting the appropriate installation location for your amplifier is perhaps the
single most important factor in ensuring a long trouble-free service life. Although the amplifier is very conservatively designed, you must provide some
airflow around the unit. If you intend to stack multiple amplifiers in an enclosed
space, you should consider installing a fan or otherwise assuring adequate
airflow around the amps, as they rely on convection cooling.
As short runs of power and speaker cabling optimize efficient energy transfer,
try to locate the amplifier close to the speakers and power source.
All models in the NT Series share a rugged chassis design that can easily be rack
mounted with machine screws (#10 or M5). While the vast majority of weight
is in the front of each amplifier, support should be provided for the rear by a
shelf or bracket.
The amplifiers are designed to draw air in through the sides, cooling the heat
sinks, and ventilating out the top cover. To provide adequate ventilation when
racking multiple units, place a 1U spacer between amplifiers. We do not
recommend using a perforated panel.
An air inlet should be provided at the bottom of the rack, and a ventilator or
exhaust fan should be provided at the top.
4
Lexicon NT Series Amplifiers
Lexicon amplifiers do not require any specialized line conditioners, as they have
special power supply circuitry designed to reject power line problems like line
spikes, surges and RFI. Simply plug each amplifier directly into a line socket. In
areas where there is a high likelihood of lightning strikes or other potentially
catastrophic surges, additional protection may be warranted. Verify that any
surge protection device you choose has ample power conducting capabilities.
High power installations may benefit from a review of your electrical service to
ensure that adequate power is available and to minimize the chance of ground
loops.
Amplifiers rated for 120V may be used only on a 60Hz line.
Complete all audio input and output connections and make sure that the front
panel power switch is in the OFF (out) position before connecting the AC power
cord.
Never make or break any connection unless power to the amplifier has been
disconnected. Unless you are bridging channels, make sure the mode switch
adjacent to the input is set to individual.
Gain level is automatically matched to the type of input used when you select
the unbalanced (RCA type connectors) or balanced mode (XLR or 1/4") with the
rear panel switch.
Power
Requirements
Audio
Connections
Use high quality speaker cables of at least 16 gauge. For runs longer than 3
meters, thicker (lower AWG#) cable should be used. The total loop resistance
of the speaker wire should be less than 0.1Ω. Consult your dealer for specific
recommendations.
All input and output connectors are gold plated and should be used with high
quality cable with gold plated connectors for optimal low-distortion and
reliable signal transfer.
One of the biggest challenges in large audio and video systems is minimizing
the audio hum caused by a “ground loop”. Raising the amplifier rear panel
Ground Lift switch to its up position puts a 10Ω resistor in series between the
system ground and the chassis ground. The chassis is still grounded.
This may reduce the hum. Do NOT leave the ground lifted if it does not make
a difference.
Often hum is caused in A/V systems through connection to cable TV cables or
other equipment which are at a different ground potential. Addressing this at
the source is the most efficient path to a clearer, quieter system.
Ground Lift Switch
The Ground Lift Switch does not
disconnect the chassis from the third
prong on the power cord which must
be left intact for safety reasons.
5
Lexicon NT Series Amplifiers
Operation
Front Panel LEDs All amplifiers in the Lexicon NT Series are equipped with sophisticated com-
parator circuits which detect sources of signal distortion including clipping,
excessive DC or supersonic signals, and short circuits in the cabling. Multifunction LEDs on the front panel are provided to alert you to various operational states of the amplifier.
In normal operation, the front panel LEDs will be lit green, indicating that
power is on and the unit is in normal operation.
The LEDs will light yellow when the amplifier is at the threshold of clipping.
Red indicates actual overload or distortion. Turn the volume down immediately! — The speaker you save may be your own!
NOTE: The Lexicon NT Series amplifiers are quite powerful and can
damage almost any speaker if used carelessly. Lexicon is not responsible for speaker damage nor is it reasonable to expect the speaker
manufacturer to honor warranty claims on speakers that have been so
abused.
Remote Trigger
When the amplifier is turned off, it is normal for the individual LEDs to dim at
differing rates, sometimes changing color as well. If one or more LEDs fail to
light up, disconnect the power cord and check the fuses next to the power cord.
CAUTION: Replace fuses only when the power cord is detached from
the amplifier and with the type and size of fuses listed on the amplifier
rear panel.
The Lexicon CP-3
PLUS
and all of the DC-1 series of Digital Controllers provide
a low voltage trigger signal when they are in operation. This signal can be used
to turn on as many as 4 amplifiers whenever you turn on your processor.
(Contact Lexicon if you need to turn on more than 4 amplifiers.)
The timing of the Turn ON function is controlled by a six-position rotary switch
on the amplifier. The delay function is provided to allow sequential power-up
of multiple amplifiers, minimizing potential power line disruptions by staggering the Turn ON times. At the 0 setting, the amplifier will turn on immediately
when it receives the 5V trigger signal. Positions 1-4 will give delays of approximately 1-4 seconds, respectively, before power up.
The input trigger circuit is completely solid-state, and draws 33mA during the
maximum delay (4 seconds), and 16mA when ON. It will accept signals from
3.8-20V. To connect a trigger signal, loosen the small screw in the round hole
above the rectangular wire terminal opening. Strip off a few millimeters of wire
insulation, and insert the bare wire into the rectangular opening. Tighten the
screw, and make sure that the wire is held captive.
6
Wire multiple amplifier triggers in parallel. Common “zip cord” wire is
adequate. (If you find that using audiophile cable for the trigger signal sounds
better, feel free to use it, just don’t tell anyone else.)
Lexicon NT Series Amplifiers
The pin outs on the CP-3
PLUS
and DC-1 series have appropriate signals available
via the rear panel DIN connectors. Pin 1 is ground and Pin 3 is +5V. (On the DC1, Pin 3 may be +12V, depending on an internal jumper configuration, but either
5V or 12V will work.)
All of the Lexicon amplifiers, with the exception of the 501, which is singlechannel, can be bridged, doubling the normal output voltage. Please refer to the
rear panel diagram for each model for specific wiring information. Note that
only the red colored output connectors are used in bridged operation. To ensure
consistent polarity, note the + and – markings on the bridged operation wiring
diagram on the amplifier rear panel.
No sound Check setting of the input connector type (BAL/
UNBAL) and operation mode (BRIDGED/INDIVIDUAL).
Check the speaker cable wiring on the rear panel and
verify correct configuration for individual or bridged
operation.
Use another amplifier channel to verify that the input
signal is good. Use another speaker to verify that the
speaker is not faulty.
Bridged Operation
Troubleshooting
No LEDs Check the power cord connection.
Disconnect power cord from amplifier, and check rear
panel fuses.
Check front panel power switch is ON.
Turn Remote ON/OFF switch to LOCAL. If amplifier
turns on, check voltage of the trigger signal at the input.
It must be at least 3.8 volts.
LEDs continuously
red or yellow Check input and output cables for short circuits. If
LEDs remain red or yellow, disconnect the power and
contact Lexicon Customer Service at (617) 736-0300, or
your local dealer.
Your Lexicon amplifier requires no maintainence. It is, however, good electrical
practice to clean all connectors once a year. An occasional dusting of the exterior
surface with a soft cloth helps maintain the unit’s luster. Do not use any abrasive
chemicals or cleaners as this will damage the surface.
Maintenance
7
Lexicon NT Series Amplifiers
Specifications
Models 212,312,412 120 Watts per channel @ 8Ω, 200 watts @ 4Ω
Input Sensitivity 1V for 28.28 VRMS (Approximately 100 watts into 8Ω)
Input Impedance 50 kΩ
Damping Factor Individual mode: >500 (20 Hz into 8Ω)
Bridging channels yields 400 Watts @ 8Ω
Model 225 250 Watts per channel @ 8Ω, 400 Watts @ 4Ω
Bridging channels yields 800 Watts @ 8Ω
Model 501 500 Watts @ 8Ω, 800 Watts @ 4Ω
S/N >110dB
IM + THD <0.01%
Slew Rate 60 V/µs
Bridged mode>250 (20 Hz into 8Ω)
Model 501>300 (20 Hz into 8Ω)
Radiated Interference <3 gauss RMS within 2"of case
Polarity Non-inverting
Controls and Indicators Power on/off
3-color LEDs indicates operational status
Toggle switches for:
bridged/individual operation (212, 225, 312, 412)
series/parallel operation (501)
balanced/unbalanced operation (all models)
6-position rotary switch for remote trigger delay
Connectors All connectors are gold plated.
Inputs: Balanced 1/4" tip-ring-sleeve and XLR
Outputs: heavy-duty 5-way binding posts
Remote Trigger input accepts bare wire, 18 gauge or smaller
3-pin IEC power connector
General Dimensions: 212: 17.0"X x 5.25"H x 9"D
225, 312 412, 501: 17.0"X x 5.25"H x 15.5"D
120V configurations available with 19" x 3U high
rack mount faceplate
Weight: 212: 22lbs net; 26lbs shipping
225: 40lbs net; 45lbs shipping
312: 33lbs net; 38lbs shipping
412: 44lbs net; 49lbs shipping
501: 44lbs net; 49lbs shipping
Power
Requirements: 120VAC, 60Hz or 230VAC, 50Hz.
All specifications subject to change without notice.
8
Lexicon Inc.
3 Oak Park
Bedford, MA 01730
Tel 781-280-0300
Fax 781-280-0490
www.lexicon.com
Lexicon Part # 070-11325
Printed in Canada
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