Jeff Rowland Design Group 302 User Manual

Model 302

Stereo Power Amplifier

Owner’s Manual

Table of ContentsTable of Contents

Introduction.......................................................................................................................................4

Product Features...............................................................................................................................5

Initial Inspection.................................................................................................................................7

Package Contents.............................................................................................................................7

Unpacking the Amplifier.....................................................................................................................9

Maintenance, Cleaning, and Protection..........................................................................................11

Installation, Use, and Care...............................................................................................................12

Front Panel Functions and Indicators...............................................................................................15

Rear Panel Power Connections........................................................................................................17

Rear Panel Signal Connections........................................................................................................19

Internal Adjustments........................................................................................................................20

Specifications..................................................................................................................................21

Dimensions......................................................................................................................22

Additional and Contact Information................................................................................................23

3333

IntroductionIntroduction

Welcome to the Jeff Rowland Design Group “family” and congratulations on your purchase of what is

unquestionably one of the world's finest audio power amplifiers. With its combination of features such

as numerous function control and interconnect possibilities, precision electronic circuitry, exceptional

efficiency, and accurately machined chassis components throughout, your Model 302 Stereo Power

Amplifier will offer you many years of musically 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 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 302 Stereo

Amplifier serial number begins with the letter “T.” This number is recorded below and is also located on

the rear panel of the chassis. Please include this number with any correspondence regarding your

Model 302 Stereo Amplifier. It has been my joy to create an audio component of enduring value that

reflects the higher ideals of musical and artistic expression. It is my hope that these qualities will enrich

your experience of ownership.

Enjoy the music!

Jeff Rowland

President,

Jeff Rowland Design Group

P.O. Box 7231 Colorado Springs, Colorado 80933

Tel: 719-473-1881 Fax: 719-633-4158 E-mail: jrdg@jeffrowland.com Web: www.jeffrowland.com

Tel: 719-473-1881 Fax: 719-633-4158 E-mail: jrdg@jeffrowland .com Web: www .jeffrowland.com

44

Product FeaturesProduct Features

! XLR input connectors for balanced system configuration.

! RCA input connectors for unbalanced system configurations.

! 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.

! Ultra-high efficiency output section generates high power output with very little heat.

! Fully-balanced circuit topology implemented from input to output.

! Power Factor correction in power supply reduces AC line harmonic 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.

! CE approved speaker output terminals require no tools for secure, low resistance connections.

! Standby power mode reduces warm-up time.

! Fail-safe operation provided by user-resetable thermal circuit breaker located on rear panel.

! Quiet, transient-free operation during power ON/OFF and input configuration switching.

! Selectable overall gain of 26 or 32 dB.

! Ultra-low resonance, structurally rigid chassis constructed of precision-machined aircraft grade

6061-T6 aluminum.

! 3-point self-leveling chassis support.

55

Package ContentsPackage Contents

AC Power CableAC Power Cable

CareCare

Care and Maintenance

Instruction Card

Compliant Isolation

Pads

WARRANTY REGISTRATIONWARRANTY REGISTRATION

Warranty CardWarranty Card

Owner’s ManualOwner’s Manual

Model 302 Stereo Power AmplifierModel 302 Stereo Power Amplifier

66

Initial InspectionInitial Inspection

Inspect the shipping container for damage. If 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)

accessories are damaged or missing, notify your dealer and the shipper (if a claim is to be made) immediately. Note: Many shippers require notification and inspection within twenty-four hours of

immediately. Note: Many shippers require notification and inspection within twenty-four hours of

delivery to determine the nature of damages incurred.

Your Model 302 Stereo Power Amplifier has undergone extensive performance evaluations, listening

Your Model 302 Stereo Power Amplifier has undergone extensive performance evaluations, listening tests, quality control inspections, and a minimum seventy-two hour burn-in period prior to shipment

tests, quality control inspections, and a minimum seventy-two hour burn-in period prior to shipment and should therefore be in perfect operating condition upon receipt. If the amplifier does not

and should therefore be in perfect operating condition upon receipt. If the amplifier does not operate correctly, please notify your dealer immediately.

operate correctly, please notify your dealer immediately.

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

We strongly suggest that you save all packing materials. If the amplifier is returned to your dealer or Jeff Rowland Design Group, the original packing materials must be used for shipment to avoid damage.

Rowland Design Group, the original packing materials must be used for shipment to avoid damage. Neither Jeff Rowland Design Group nor the shipper can be held responsible for damages incurred

Neither Jeff Rowland Design Group 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 Jeff Rowland

during transit if the original factory packing is not used. All factory returns require that Jeff Rowland Design Group issue a Return Authorization (RA) number prior to shipment.

Design Group issue a Return Authorization (RA) number prior to shipment.

ContentsContents

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

accessory box. Refer to the diagrams illustrated on the adjacent page and verify that the proper

accessory box. Refer to the diagrams illustrated on the adjacent page and verify that the proper components are included.

components are included.

1 One (1) AC Power Cable

2 One (1) Warranty Card (In some countries, warranties are provided by the respective importer.)

3 One (1) Care and Maintenance Instruction Card

4 One set of three (3) Compliant Isolation Pads

5 One (1) Owner’s Manual

6 One (1) Model 302 Stereo Power Amplifier

77

Unpacking the AmplifierUnpacking the Amplifier

111111

22

33

44

55

88

Unpacking the AmplifierUnpacking the Amplifier

The Model 302 is a large and heavy amplifier. Due caution should be taken when unpacking and

The Model 302 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 302 should be unpacked

installing the amplifier to avoid injury or damage to the amplifier. The Model 302 should be unpacked by at least two people, however it is possible for one person to unpack the amplifier safely. There

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

should be a portion of carpet or soft, padded cloth to stand the amplifier on when unpacking it from the shipping box.

the shipping box.

To unpack the amplifier:

K Stand the shipping box vertically and open one end of both the inner and outer box.

L Pull all box flaps back and turn the carton so that it is standing face-down onto the open end.

M Carefully lift both boxes up and off of the amplifier and packing material.

N Remove the packing material cap from the upper end of the amplifier and untie the

protective cloth bag. Pull the cloth bag back to expose the amplifier.

O Lay the amplifier down on its feet. Remove the remaining packing cap and the cloth bag .

The amplifier is now ready for installation.

99

Amplifier Maintenance, Cleaning, and ProtectionAmplifier Maintenance, Cleaning, and Protection

1010

Amplifier Maintenance, Cleaning, and ProtectionAmplifier Maintenance, Cleaning, and Protection

Maintenance and Cleaning

All Jeff Rowland Design Group products are designed to provide a lifetime of enjoyment and listening

pleasure. The chassis is sealed to prevent dust from entering and the interior of the chassis should not

pleasure. The chassis is sealed to prevent dust from entering and the interior of the chassis should not need cleaning during the lifetime of the product. All internal circuitry is self-adjusting such that no

need cleaning during the lifetime of the product. All internal circuitry is self-adjusting such that no adjustments or maintenance of any kind are necessary over the lifetime of the product. If the

adjustments or maintenance 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

amplifier is ever in need of service, updating, or upgrading, it should only be returned to an authorized repair facility or technician for servicing.

repair facility or technician for servicing.

The Model 302 Stereo Power Amplifier is uniquely constructed from a number of precision machined

The Model 302 Stereo Power Amplifier is uniquely constructed from a number of precision machined aluminum subassemblies. The front panel of the unit is machined in a unique process that

aluminum subassemblies. The front panel of the unit is machined in a unique process that incorporates a diamond tipped cutting tool. This process was refined over many years to produce an

incorporates a diamond tipped cutting tool. This process was refined over many years to produce an artistic and attractive finish.

artistic and attractive finish.

Because the surface is not finished in the typical fashion of most audio and video equipment, there

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.

are a few rules that must be kept in mind when cleaning the equipment.

! Please allow the front panel 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

small scratches from marring the surface before the surface coating has had a chance to harden completely.

harden completely.

! The top cover, sides, and bottom cover can all be cleaned with a soft cotton cloth (such as an

optical lens cleaning cloth or fine furniture polishing rag) dampened with plain water. Water

optical lens cleaning cloth or fine furniture polishing rag) dampened with plain water. Water should be applied directly to the cloth and not the chassis. If a mark has been left on the

should be applied directly to the cloth and not the chassis. If a mark has been left on the chassis, do not use any type of abrasive or chemical cleaner to remove the mark. A very mild

chassis, do not use any type of abrasive or chemical cleaner to remove the mark. A very mild plastic or glass cleaner that does not contain ammonia should be tried only as a last resort.

plastic or glass cleaner that does not contain ammonia should be tried only as a last resort.

! Please contact the factory before trying any type of cleanser on the chassis other than water to

clean the unit.

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

cloth and plain water or fine oil-based furniture polish. Because of the fine finish of the front

cloth and plain water or fine oil-based furniture polish. Because of the fine finish of the front panel, small scratches from the use of any other agent to clean the front panel will become

panel, small scratches from the use of any other agent to clean the front panel will become very visible.

very visible.

If you have any questions about the care or cleaning of your Model 302 amplifier, please contact your

If you have any questions about the care or cleaning of your Model 302 amplifier, please contact your dealer or the Jeff Rowland Design Group factory before attempting to clean the chassis. The use of a

dealer or the Jeff Rowland Design Group 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

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.

certainly damage the finish and will not be covered under warranty.

Protection Systems

The Model 302 Stereo Power Amplifier is equipped with active circuitry and thermal circuit breakers for

protection against excessive AC mains voltage. However, since no protection circuitry or system can

protection against excessive AC mains voltage. However, since no protection circuitry or system can completely protect a product from every electrical hazard, certain precautions should be observed.

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

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

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

damage to the internal circuitry. All other audio/video system components should also be disconnected from AC mains power as hazardous voltages can travel throughout an interconnected

disconnected from AC mains power as hazardous voltages can travel throughout an interconnected system.

system.

1111

Amplifier Installation, Use, and CareAmplifier Installation, Use, and Care

Locate the amplifier as close as possible to its final installation point. Allow access to the rear panel for

making connections.

The Model 302 Stereo Power Amplifier is extremely efficient and convection cooled, eliminating the

The Model 302 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

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

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.

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

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

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

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

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

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

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

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.

resonant energy from the support structure to the amplifier chassis.

For rack-mounted or custom applications, a rack-mountable faceplate can be ordered and

For rack-mounted or custom applications, a rack-mountable faceplate can be ordered and manufactured by Jeff Rowland Design Group. Please contact your dealer or distributor with questions

manufactured by Jeff Rowland Design Group. Please contact your dealer or distributor with questions about custom rack-mountable faceplates and delivery times. Note: Please keep in mind that the

about custom rack-mountable faceplates and delivery times. Note: Please keep in mind that the

Model 302 is a very heavy amplifier and that additional support will be required from beneath the

Model 302 is a very heavy amplifier and that additional support will be required from beneath the amplifier. The faceplate alone is not sufficient support for total weight of the amplifier!

amplifier. The faceplate alone is not sufficient support for total weight of the amplifier!

The Jeff Rowland Design Group Model 302 Stereo Power Amplifier has been designed with

comprehensive protection circuits that allow the amplifier to operate at the highest level of efficiency

comprehensive protection circuits that allow the amplifier to operate at the highest level of efficiency and performance in any normal operating situation. However, there are a few important use and

and performance in any normal operating situation. However, there are a few important use and care principles that must be kept in mind when operating the amplifier:

care principles that must be kept in mind when operating the amplifier:

! Do not expose the amplifier to rain, moisture, or excessively damp conditions.

! Do not expose the amplifier to rain, moisture, or excessively damp conditions. ! Do not disconnect the amplifier from AC mains unless absolutely necessary and without first

! Do not disconnect the amplifier from AC mains unless absolutely necessary and without first

placing the amplifier in Standby mode.

! The Model 302 Stereo Power Amplifier must not be modified in any way, other than according

to official service bulletins from Jeff Rowland Design Group. Other wise, the factory warranty will

to official service bulletins from Jeff Rowland Design Group. Other wise, the factory warranty will be immediately voided.

be immediately voided.

! The Model 302 Stereo Power Amplifier can be operated at a nominal 100, 120, 220, or 240

volts AC. The amplifier must be wired for the correct AC input voltage before operation or

volts AC. The amplifier must be wired for the correct AC input voltage before operation or serious damage will result.

serious damage will result.

! To clean the Model 302 Stereo Power Amplifier, use a soft cloth moistened with plain water.

Never apply water, dusting sprays, solvents, abrasives, or cleaning fluids directly to the chassis!

! Be sure the amplifier is in STANDBY mode (front panel indicator light OFF) before connecting or

disconnecting any loudspeaker or interconnect cables.

1212

Amplifier Installation, Use, and Care (Cont.)Amplifier Installation, Use, and Care (Cont.)

! When operating the Model 302, 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

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.

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

ground. Shorting of the outputs will result in damage to the output section.

! The Model 302 is designed to perform optimally with no adjustments or maintenance. In the

event of servicing, do not attempt to open the top cover of the amplifier and refer all service

event of servicing, do not attempt to open the top cover of the amplifier and refer all service issues to qualified personnel. The voltages inside the Model 302 can be hazardous.

issues to qualified personnel. The voltages inside the Model 302 can be hazardous.

1313

Amplifier Front Panel Functions and IndicatorsAmplifier Front Panel Functions and Indicators

1414

Front Panel

Power/Standby Button

Front Panel

Power/Standby Indicator

Amplifier Front Panel Functions and IndicatorsAmplifier Front Panel Functions and Indicators

Before attempting any system interconnection, please familiarize yourself with the front panel control

of the Model 302 Stereo Power Amplifier. The descriptions below refer to the illustration on the adjacent

of the Model 302 Stereo Power Amplifier. The descriptions below refer to the illustration on the adjacent page.

page.

FRONT PANEL STANDBY/POWER BUTTON: Press this button to operate the amplifier. Press again to

place the amplifier in Standby mode.

FRONT PANEL STANDBY/POWER INDICATOR: This small, blue light will illuminate when the amplifier is

operational. When the light is not illuminated, all amplifier inputs are muted and internal circuitry

operational. When the light is not illuminated, all amplifier inputs are muted and internal circuitry reverts to power-saving (Standby) mode.

reverts to power-saving (Standby) mode.

To avoid spurious noises and possible damage to the amplifier's internal circuitry, the amplifier should

To avoid spurious noises and possible damage to the amplifier's internal circuitry, the amplifier should be switched to Standby mode when connecting or disconnecting any rear panel connections.

be switched to Standby mode when connecting or disconnecting any rear panel connections.

Note: All ON/OFF power switching should be initiated ONLY with this button. The amplifier should not

be disconnected from AC power without first placing the amplifier in Standby mode. Avoid the use of

be disconnected from AC power without first placing the amplifier in Standby mode. Avoid the use of switched AC power outlets to control or switch AC power to the amplifier.

switched AC power outlets to control or switch AC power to the amplifier.

1515

Amplifier Rear Panel Power ConnectionsAmplifier Rear Panel Power Connections

UNBALANCED

INPUT

RIGHT

RIGHT INPUT

INPUT

SELECT

NEUTRIKNEUTRIK

BALANCED

INPUT

PUSHPUSH

MODEL 302MODEL 302MODEL 302

STEREO POWER AMPLIFIERSTEREO POWER AMPLIFIERSTEREO POWER AMPLIFIER

MADE IN U.S.A.MADE IN U.S.A.MADE IN U.S.A.

UNBALANCED

INPUT

LEFT

INPUT

SELECT

NEUTRIKNEUTRIK

SELECT

PUSHPUSH

BALANCED

INPUT

NUMBER

444

SERIAL

T0000

RIGHT

SPEAKER

AAA BBB

OUTPUT

ON / OFF

REMOTE

12V

111

1200 W. MAX1200 W. MAX1200 W. MAX

VOLTS ACVOLTS ACVOLTS AC

333

AAA

AC MAINSAC MAINSAC MAINS

PUSH TO RESETPUSH TO RESETPUSH TO RESET

SPEAKER

OUTPUT

5

A

A M

M

M P

P

LEFT

BBB

CAUTIONCAUTIONCAUTION

TO PREVENT FIRE OR SHOCK HAZARD, DO NOT

TO PREVENT FIRE OR SHOCK HAZARD, DO NOT REMOVE COVER. DO NOT EXPOSE TO RAIN OR

REMOVE COVER. DO NOT EXPOSE TO RAIN OR

REMOVE COVER. DO NOT EXPOSE TO RAIN OR MOISTURE. NO USER SERVICEABLE PARTS INSIDE.

MOISTURE. NO USER SERVICEABLE PARTS INSIDE.

MOISTURE. NO USER SERVICEABLE PARTS INSIDE. REFER SERVICING TO QUALIFIED SERVICE PERSONNEL.

REFER SERVICING TO QUALIFIED SERVICE PERSONNEL.

REFER TO OWNERS MANUAL BEFORE OPERATING.

222

1616

Amplifier Rear Panel Power ConnectionsAmplifier Rear Panel Power Connections

Important: Please strictly follow the following steps outlined below in order before operating your

Model 302 Stereo Power Amplifier.

K Verify that the VOLTS AC input identified on the rear panel near the AC input socket is the

same as the AC mains voltage in your area. If the voltage does not match, DO NOT

CONNECT THE AMPLIFIER TO AC POWER and contact your dealer immediately.

L Verify that the AC MAINS circuit breaker is closed (no white area visible on breaker).

M Install the AC Power Cable between the amplifier and your AC mains outlet.

N Connect the 12V Remote ON/OFF Mini-plug Connector (See Below).

Note: Due to the exceptionally low power consumption rating of the Model 302, it is recommended

that the unit not be disconnected from AC mains unless the amplifier is to be moved or reinstalled in

that the unit not be disconnected from AC mains unless the amplifier is to be moved or reinstalled in another location. It is recommended that the amplifier be placed in Standby mode rather than

another location. It is recommended that the amplifier be placed in Standby mode rather than disconnected from the AC mains power when the amplifier is not in use.

disconnected from the AC mains power when the amplifier is not in use.

The 12V REMOTE ON/OFF 1/8” (3.5 mm) mini-plug connector (4) is provided on the rear panel of the

Model 302 for remotely switching the amplifier between Operational and Standby modes. When

Model 302 for remotely switching the amplifier between Operational and Standby modes. When connected to another component with the proper circuitry, the amplifier standby function can be

connected to another component with the proper circuitry, the amplifier standby function can be turned ON and OFF remotely in a custom installation, theater, or automated system setup.

turned ON and OFF remotely in a custom installation, theater, or automated system setup. Connection requirements are illustrated below.

Connection requirements are illustrated below.

Please be aware that the remote feature simply places the amplifier in STANDBY mode and does not

Please be aware that the remote feature simply places the amplifier in STANDBY mode and does not disconnect the unit from power or AC mains.

disconnect the unit from power or AC mains.

Please contact your dealer for further information about the use and configuration of this feature.

Constant 3V to 15V DC Signal

(12VDC Typical)

GroundGround

Detail of Mini-plug ConnectorDetail of Mini-plug Connector

1717

Amplifier Rear Panel Signal ConnectionsAmplifier Rear Panel Signal Connections

UNBALANCED

INPUT

BALANCED

INPUT

333

RIGHT

RIGHT INPUT

INPUT

SELECT

111

NEUTRIKNEUTRIK

PUSHPUSH

222

UNBALANCED

INPUT

LEFT

INPUT

SELECT

NEUTRIKNEUTRIK

SELECT

PUSHPUSH

BALANCED

INPUT

MODEL 302MODEL 302MODEL 302

STEREO POWER AMPLIFIERSTEREO POWER AMPLIFIERSTEREO POWER AMPLIFIER

MADE IN U.S.A.MADE IN U.S.A.MADE IN U.S.A.

1818

SERIAL

NUMBER

T0000

RIGHT

SPEAKER

AAA BBB

OUTPUT

555

REMOTE

ON / OFF

12V

1200 W. MAX1200 W. MAX1200 W. MAX

VOLTS ACVOLTS ACVOLTS AC

AAA

AC MAINSAC MAINSAC MAINS

PUSH TO RESETPUSH TO RESETPUSH TO RESET

SPEAKER

OUTPUT

5

A

A M

M

M P

P

LEFT

BBB

CAUTIONCAUTIONCAUTION

TO PREVENT FIRE OR SHOCK HAZARD, DO NOT

TO PREVENT FIRE OR SHOCK HAZARD, DO NOT REMOVE COVER. DO NOT EXPOSE TO RAIN OR

REMOVE COVER. DO NOT EXPOSE TO RAIN OR

REMOVE COVER. DO NOT EXPOSE TO RAIN OR MOISTURE. NO USER SERVICEABLE PARTS INSIDE.

MOISTURE. NO USER SERVICEABLE PARTS INSIDE.

MOISTURE. NO USER SERVICEABLE PARTS INSIDE. REFER SERVICING TO QUALIFIED SERVICE PERSONNEL.

REFER SERVICING TO QUALIFIED SERVICE PERSONNEL.

REFER TO OWNERS MANUAL BEFORE OPERATING.

444

Amplifier Rear Panel Signal ConnectionsAmplifier Rear Panel Signal Connections

The Model 302 Stereo Power Amplifier offers unprecedented compatibility with associated audio

components. When connecting or disconnecting speaker or interconnect cables, the amplifier

components. When connecting or disconnecting speaker or interconnect cables, the amplifier should be placed in Standby mode (blue POWER INDICATOR LED on the front panel OFF).

should be placed in Standby mode (blue POWER INDICATOR LED on the front panel OFF).

If you are using balanced XLR interconnects from your preamplifier or source component, position the

INPUT SELECT switch (1) to BALANCED INPUT. If you are using unbalanced RCA interconnects, position

INPUT SELECT switch (1) to BALANCED INPUT. If you are using unbalanced RCA interconnects, position the INPUT SELECT switch to UNBALANCED INPUT.

the INPUT SELECT switch to UNBALANCED INPUT.

Connect the corresponding interconnect cables to either the BALANCED INPUTS (2) or UNBALANCED

INPUTS (3) on each channel. Both RCA and XLR inputs cannot be used for the same channel

INPUTS (3) on each channel. Both RCA and XLR inputs cannot be used for the same channel simultaneously. For example, an unbalanced output connection from a surround processor and a

simultaneously. For example, an unbalanced output connection from a surround processor and a balanced output connection from a CD player cannot both be connected to the same channel at

balanced output connection from a CD player cannot both be connected to the same channel at the same time.

the same time.

A slight mechanical click may be heard when the balanced XLR interconnect cables are correctly

A slight mechanical click may be heard when the balanced XLR interconnect cables are correctly installed and locked. The unlocking tab (located on the input connector and labeled “PUSH”) must be

installed and locked. The unlocking tab (located on the input connector and labeled “PUSH”) must be pressed to disconnect the XLR interconnect cable from the amplifier.

pressed to disconnect the XLR interconnect cable from the amplifier.

Unscrew the knob that secures the speaker output connectors on both the LEFT SPEAKER OUTPUT (4)

Unscrew the knob that secures the speaker output connectors on both the LEFT SPEAKER OUTPUT (4) and the RIGHT SPEAKER OUTPUT (5) and pull the securing block out far enough to allow access to the

and the RIGHT SPEAKER OUTPUT (5) and pull the securing block out far enough to allow access to the binding posts. Install the positive (usually red) loudspeaker cable spade terminal to the positive (+)

binding posts. Install the positive (usually red) loudspeaker cable spade terminal to the positive (+) binding post and the negative spade terminal to the negative (-) binding post on both the LEFT (4) and

binding post and the negative spade terminal to the negative (-) binding post on both the LEFT (4) and RIGHT (5) CHANNEL. Secure the loudspeaker connections by tightening the knob securely with your

RIGHT (5) CHANNEL. Secure the loudspeaker connections by tightening the knob securely with your fingers.

fingers.

The Model 302 will only accept spade terminations for loudspeaker cables. Banana plugs or bare wire

The Model 302 will only accept spade terminations for loudspeaker cables. Banana plugs or bare wire connections cannot be used and must be reterminated with spade connections.

connections cannot be used and must be reterminated with spade connections.

The Model 302 has two pairs of binding posts per channel to facilitate bi-wiring. Both sets of binding

posts are active and connected in parallel with no difference in signal quality. If your loudspeakers are

posts are active and connected in parallel with no difference in signal quality. If your loudspeakers are capable of bi-wiring and you wish to do so, simply connect one pair of binding posts from each

capable of bi-wiring and you wish to do so, simply connect one pair of binding posts from each channel to the high frequency terminals of your loudspeakers and one pair of each channel to the low

channel to the high frequency terminals of your loudspeakers and one pair of each channel to the low frequency terminals of your loudspeakers.

frequency terminals of your loudspeakers.

+ Warning: Both positive and negative outputs are electrically active with respect to chassis

and/or system ground potential. Therefore, this amplifier cannot be used in certain loudspeaker

and/or system ground potential. Therefore, this amplifier cannot be used in certain loudspeaker switching configurations, such as those used in retail demonstrations. Failure to avoid these

switching configurations, such as those used in retail demonstrations. Failure to avoid these precautions may short the outputs to ground and can result in damage to the amplifier and will void

precautions may short the outputs to ground and can result in damage to the amplifier and will void the warranty.

the warranty.

1919

Internal AdjustmentsInternal Adjustments

Overall Gain

The overall gain of the Model 302 Stereo Power Amplifier can be adjusted between 26 dB and 32 dB.

The setting from the factory is 26 dB, which is adequate for the majority of applications, though some

The setting from the factory is 26 dB, which is adequate for the majority of applications, though some systems involving low efficiency loudspeakers may require the higher gain setting. There is no sonic

systems involving low efficiency loudspeakers may require the higher gain setting. There is no sonic difference between the two settings.

difference between the two settings.

Because of the potentially dangerous voltages inside of the chassis, it is recommended that you

Because of the potentially dangerous voltages inside of the chassis, it is recommended that you contact your dealer for information regarding the overall gain setting adjustments.

contact your dealer for information regarding the overall gain setting adjustments.

Note: Do not attempt to disassemble the chassis of the amplifier and adjust the gain without explicit

instructions from your dealer or Jeff Rowland Design Group.

2020

Model 302 Stereo Power Amplifier SpecificationsModel 302 Stereo Power Amplifier Specifications

Output Power:

Continuous RMS watts, both channels driven

Continuous RMS watts, both channels driven @ 8 ohms

@ 8 ohms @ 4 ohms

@ 4 ohms

Power Bandwidth:

Peak Output Current:

Dynamic Range:

THD + Noise, 0.1W-500W/4 ohm:

CCIF Intermodulation Distortion, 19/20 kHz:

Damping Factor @ 1kHz:

Overall Gain:

Overall Gain: (Balanced or Unbalanced)

(Balanced or Unbalanced)

300 watts.

300 watts. 500 watts.

500 watts.

5 Hz - 60 kHz, -3 dB.

>45 Amps.

117 dBA.

<.05%, typically .006 @ 1kHz.

<.002%.

275.

Selectable Internal Jumper,

Selectable Internal Jumper, 26 or 32 dB.

26 or 32 dB.

Input Impedance:

Common Mode Rejection Ratio:

Absolute Phase:

Inputs:

Outputs:

Power Consumption:

Standby Switch OFF

Standby Switch OFF Standby Switch ON (idle)

Standby Switch ON (idle) Maximum

Maximum

Amplifier Weight:

Shipping Container Dimensions:

40k ohms.

>90dB, 20 Hz - 20 kHz

Non-inverting, Pin 3 Positive.

User Selectable,

User Selectable, 2 x Balanced XLR

2 x Balanced XLR 2 x Unbalanced RCA.

2 x Unbalanced RCA.

2 Pairs Parallel Binding Posts

2 Pairs Parallel Binding Posts per Channel.

per Channel.

45 watts.

45 watts. 55 watts.

55 watts. 1200 watts.

1200 watts.

95 lbs./43 kg.

27” (L) x 21” (W) x 16” (H)/

27” (L) x 21” (W) x 16” (H)/ 68 cm (L) x 54 cm (W) x 41 cm.

68 cm (L) x 54 cm (W) x 41 cm.

Shipping Weight:

103 lbs./47 kg.

2121

DimensionsDimensions

A summary of the amplifier chassis dimensions is indicated below.A summary of the amplifier chassis dimensions is indicated below.

18.3 in. (46.9 cm)18.3 in. (46.9 cm)

10.0 in. (25.4 cm)10.0 in. (25.4 cm)

15.5 in. (39.4 cm)15.5 in. (39.4 cm)

14.5 in. (36.8 cm)14.5 in. (36.8 cm)

16.0 in. (40.6 cm)16.0 in. (40.6 cm)

10.6 in. (26.9 cm)10.6 in. (26.9 cm)

2222

Additional InformationAdditional Information

If you have any additional questions regarding the installation or operation of the Model 302 Stereo

Power Amplifier, please contact your authorized Jeff Rowland Design Group dealer or check the Jeff

Power Amplifier, please contact your authorized Jeff Rowland Design Group dealer or check the Jeff Rowland Design Group web site at http://www.jeffrowland.com.

Rowland Design Group web site at http://www.jeffrowland.com.

2323

Jeff Rowland Design Group 302 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual