JEFF ROWLAND 312 User manual

OWNER’S MANUAL MODEL 312 STEREO AMPLIFIER

TABLE OF CONTENTS

OWNER’S MANUAL MODEL 312 STEREO AMPLIFIER

    

   

   

    

 

  

  

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 

  

  

PO BOX 7231, COLORADO SPRINGS, COLORADO 80933 USA E-mAIL: jRDG@jEffROwLAND.COm www.jEffROwLAND.COm TELEPHONE (719) 473-1181



If you have any additional questions

regarding the installation or operation

of the Model 312 Stereo Ampliﬁer, please

contact your authorized Jeff Rowland

Design Group dealer or check the Jeff

Rowland Design Group web site at

www.jeffrowland.com.

Enjoy the music!

Jeff Rowland

President,

Jeff Rowland Design Group

the operational features will allow you

to gain the maximum performance and

ease of use for which this ampliﬁer was

designed. Please note that your Model 312

Stereo Ampliﬁer serial number begins

with the letter “T”. This serial number is

located on the rear panel of the chassis.

Please include this number with any corre-

spondence regarding your Model 312

Stereo Ampliﬁer. It has been my joy to

create an audio component of enduring

value that reﬂects the highest ideals of

musical and artistic expression. It is my

hope that these qualities will enrich your

experience and pride of ownership.

Welcome to the Jeff Rowland Design

Group “family” and congratulations on your

purchase of what is unquestionably one

of the world’s ﬁnest ampliﬁers. With its

combination of features such as precision

electronic circuitry, exceptional

efﬁciency,

and accurately machined chassis compo-

nents throughout, your

Model 312 Stereo

Ampliﬁer will offer you many years of musi-

cally satisfying enjoyment.

Please take a few minutes to read the

remainder of this Owner’s Manual before

proceeding with the installation of the

ampliﬁer. A thorough understanding of

INTRODUCTION

OWNER’S MANUAL MODEL 312 STEREO AMPLIFIER



• XLR input connectors for balanced

system conguration.

• RCA input connectors for unbalanced

system congurations.

•

Dual Speaker Output Terminals on each

channel for bi-wiring applications.

• User selectable switching between

balanced and unbalanced connections.

• Transformer coupled inputs provide

universal compatibility with other

components and eliminate ground

loop noise and EMI.

• High efciency ICEpower® power

conversion technology generates high

output power with very little heat.

• Fully-balanced topology

implemented

in both input and output circuitry.

• Power Factor Correction (PFC) in

power supply reduces AC line har-

monic noise pollution and increases

AC line power utilization to 99%.

• Proprietary switch-mode power

supply technology ensures

consistent performance under

all operating conditions.

• 12V remote ON/OFF remote power

switching via 1/8” jack on rear panel.

• Standby power mode reduces

warm-up time.

• CE approved speaker output terminals

require no tools for secure, low resis-

tance connections.

• Fail-safe operation provided by

user-resetable thermal circuit breaker

located on rear panel.

• Quiet, transient-free operation

during power ON/OFF and input

conguration switching.

• Selectable overall gain of 26 or 32 dB.

• Ultra-low resonance, structurally

rigid chassis,

precision-machined

from a solid block of aircraft grade

6061-T6 aluminum.

• 3-point self-leveling chassis support.

PRODUCT FEATURES

OWNER’S MANUAL MODEL 312 STEREO AMPLIFIER

PO BOX 7231, COLORADO SPRINGS, COLORADO 80933 USA E-mAIL: jRDG@jEffROwLAND.COm www.jEffROwLAND.COm TELEPHONE (719) 473-1181



Ensure that all of the auxiliary components listed below are enclosed within the shipping carton and

accessory box. Refer to the illustrations and verify that the proper components are included.



WARRANTY REGISTRATION

 

OWNER’S MAN UAL MODEL 312 STEREO A MPLIFIER



PACKAGE CONTENTS

OWNER’S MANUAL MODEL 312 STEREO AMPLIFIER



Inspect the shipping container for damage. If any portion of the shipping container, packing material,

ampliﬁer, or accessories are damaged or missing, notify your dealer and the shipper (if a claim is

to be made) immediately.





Your Model 312 Stereo Ampliﬁer has undergone extensive performance evaluations, listening tests,

quality control inspections, and a minimum 72 hour burn-in period prior to shipment and should

therefore be in perfect operating condition upon delivery. If the ampliﬁer does not operate correctly,

please notify your dealer immediately.

We strongly suggest that you save all of the packing materials. If the ampliﬁer is returned to your

dealer or JRDG, the original packing materials must be used for shipment to avoid possible damage.

Neither JRDG nor the shipper can be held responsible for damages incurred during transit if the

original factory packing is not used. All factory returns require that JRDG issue a Return Authorization

(RA) number prior to shipment.

      

The Model 312 is a large and heavy

ampliﬁer. Due caution should be taken

when unpacking and installing the

ampliﬁer to avoid injury or damage to

the ampliﬁer. The Model 312 should

be unpacked by at least two people,

however it is possible for one person to

unpack the ampliﬁer safely. There should

be a portion of carpet or soft, padded

cloth to stand the ampliﬁer on when

unpacking it from the shipping box.

INITIAL INSPECTION

OWNER’S MANUAL MODEL 312 STEREO AMPLIFIER

PO BOX 7231, COLORADO SPRINGS, COLORADO 80933 USA E-mAIL: jRDG@jEffROwLAND.COm www.jEffROwLAND.COm TELEPHONE (719) 473-1181



All JRDG products are designed to provide

a lifetime of enjoyment

and listening pleasure. The Model 312 Stereo

Ampliﬁer is uniquely

constructed from precision-machined 6061-T6 aluminum sub-

assem-

blies, conﬁgured and dimensioned to maximize chassis strength and

reduce vibration. Constrained mode damping materials have also

been applied in several areas to further reduce chassis resonance.

The chassis is sealed to prevent dust from

entering the interior and

should never need interior cleaning during the lifetime of the product.

All internal circuitry is maintenance-free such that no adjustments of

any kind are necessary over the lifetime of the product. If the ampliﬁer

is ever in need of service, updating, or upgrading, it should only be

returned to an authorized repair facility or technician for servicing.

The front panel of the unit is precision-machined in a unique process

that incorporates a diamond tipped cutting tool. This process was reﬁned

over many years to produce an attractive and unique appearance.

Because the surface is not ﬁnished in the typical fashion of most

audio and video equipment, there are a few rules that must be kept

in mind when cleaning the equipment.

• Please allow the front panel, which is coated with an automotive-grade polyure-

thane nish, to cure for 6 months before attempting to clean it.

This will prevent

small scratches from marring the surface before the surface coating has had a

chance to harden completely.

• The front panel of the unit should never be cleaned with anything other than a very

soft cotton cloth and plain water or ne oil-based furniture polish. Because of the

ne nish of the front panel, use of any other cleaning agent may permanently

scratch the nish.

• The top cover, sides and bottom are protected by a durable black anodized nish

and can be cleaned with a soft cotton cloth (such as an optical lens cleaning cloth

or ne furniture polishing rag) dampened with plain water. Water should be applied

directly to the cloth and not the chassis. A very mild plastic or glass cleaner that

does not contain ammonia may also be used. If a mark has been left on the

chassis,

do not use any type of abrasive or chemical cleaner to remove the mark.

Maintenance & cleaning

OWNER’S MANUAL MODEL 312 STEREO AMPLIFIER



Protection SyStemS

If you have any questions about the care or cleaning of your Model

312 Stereo Ampliﬁer, please contact your dealer or the JRDG factory

before attempting to clean the chassis. The use of a cleanser or

abrasive to clean the chassis that has not been approved by the

factory will almost certainly damage the ﬁnish and will not be

covered under warranty.

NOTE: Cleaner/polish should be applied directly to the cloth and not the chassis.

The Model 312 Stereo Ampliﬁer is equipped with internal fuses for

protection against excessive AC current draw; however, since no

protection circuitry or system can completely protect a product from

every electrical hazard, certain precautions should be observed. In

the event

of severe voltage hazards such as lightning or when the

ampliﬁer

will not be used for extended periods of time, the ampliﬁer

should be unplugged from the AC mains to avoid potential damage

to the internal circuitry. All other audio/video system components

should also be disconnected from AC mains power as hazardous

voltages can easily travel throughout an interconnected system.

PO BOX 7231, COLORADO SPRINGS, COLORADO 80933 USA E-mAIL: jRDG@jEffROwLAND.COm www.jEffROwLAND.COm TELEPHONE (719) 473-1181



Locate the ampliﬁer as close as possible to its ﬁnal installation point.

Allow access to the rear panel for making connections.

The Model 312 Stereo Power Ampliﬁer is extremely efﬁcient and

convection cooled, eliminating the need for fans or forced-air cooling.

Multiple chassis can be stacked vertically, facilitating an upward ﬂow of

warm air currents throughout the vertical heatsink areas. This upward

ﬂow must not be blocked or recirculated around the chassis if proper

cooling is to be maintained.

Typical installations allow the ampliﬁer to be rigidly coupled to a

support structure or ﬂoor via optional spiked coupling supports that

are available separately from JRDG. In carpeted installations, these

supports provide excellent anchoring from the ampliﬁer chassis to the

rigid ﬂoor or sub-ﬂoor below. If there is concern about damage to the

structure or ﬂoor’s ﬁnish, a coin can be placed beneath each spiked

coupling support. In installations where the resonant properties of the

supporting structure are poor or unknown, the ampliﬁer chassis can be

loosely coupled to the supporting structure via the supplied compliant

isolation interface pads. This will help to attenuate the transfer of vibration

or resonant energy from the support structure to the ampliﬁer chassis.

InstallatIon, Use & care

OWNER’S MANUAL MODEL 312 STEREO AMPLIFIER

RISK OF ELECTRICAL SHOCK!

WARNING: Do not attempt to access the interior of the MODEL

312 STEREO AMPLIFIER

by removing the top or bottom cover.

Doing so will void your warranty and could expose you to

dangerous, potentially lethal electrical voltages.



• Do not expose the amplier to

rain, moisture, or excessively

damp conditions.

•

The Model 312 Stereo Amplier

must not be modied in any way,

other than according to ofcial

service bulletins from JRDG.

Otherwise, the factory warranty

will be immediately voided.

• The Model 312 Stereo Power

Amplier

can be operated at a

nominal 100, 120,

220, or 240

volts AC. The amplier must be

congured for the correct AC input

voltage before operation or serious

damage will result.

• Be sure the amplier is unplugged

from the AC mains wall plug (front

panel indicator light OFF) before

connecting or disconnecting any

loudspeaker or interconnect cables.

• When operating the Model 312, a

properly grounded AC receptacle

should be used. A potential shock

hazard may result if the supplied

3-wire, grounded AC cable ground

terminal is defeated or lifted or

the unit is connected to a 2-wire

ungrounded AC outlet.

• The output terminals or loudspeaker

cables should never be shorted to

each other or to any chassis surface.

Shorting of the outputs may result in

damage to the output section of the

amplier.

• The Model 312 is designed to per-

form

optimally with no adjustments

maintenance for the lifetime of the

product. Do not attempt to open the

bottom cover of the amplier and

refer all service issues to qualied

personnel. The voltages inside the

Model 312 can be hazardous.

The JRDG Model 312 Stereo

Ampliﬁer has been designed to

operate at the highest level of

efﬁciency and performance in

any normal operating situation;

however, there are a few impor-

tant use and care principles

that must be kept in mind when

operating the ampliﬁer.

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