Jeff Rowland Design Group 302 User's Manual
Contents
1. Cs o o J E gt c 1 E pm C p C gt gt c 1 Ez a C D E gt c 1 Ez c 1 Ez f o o 13 c 1 Es EP c 1 EP c 1 gt c 1 LI gt 1 1 WUD 9 Op ut 0 9L Additional 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 Rowland Design Group web site at http www jeffrowland com2. Model 302 Stereo Power Amplifier Owner s Manual Table of Contents INTOAUCTON ii A aaa 4 Product RSQUUISS an en O AR RITA RITA 5 Iri SpecTi Obi touc t roe add AA A ear 7 PAIS CON dada 7 Unpacking Ms Ample sine EE ELLO A A AAE OE A EEA 9 Maintenance Cleaning and Protection 1 IFSTOMGTION USCIS CIC criari iaia 12 Frorit PanelFEunctiens and Indicalors ici iti 15 Rear Panel Power SOMMECHIONS ciare anti 17 Rear Panel Signal CONS Sii da o aa 19 Intemal Adjustrremnts ce tet vid va vetri eder A it 20 SOSGITICOTIOMS i I D DE anali Raina 21 Bins sale PRE E IE 22 Additi nal and Contact IN OMAN nos vid itt et but fe to nonet sai 23 Introduction 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 se
3. 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 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 For rack mounted or custom applications a rackmountable faceplate can be ordered and manufactured by Jeff Rowland Design Group Please contact your dealer or distributor wit
4. 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 Package Contents WARRANTY REGISTRATION e v menge UE Compliant Isolation AC Power Cable Pads Warranty Card Care and Maintenance Instruction Card Owner s Manual a N DESIGN GROUP oo ooo Model 302 Stereo Power Amplifier Initial 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 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 tests quality control inspections and a minimum seventytwo hour burn in period prior to shipment and should ther
5. ATOR 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 reverts to power saving Standby mode To avoid spurious noises and possible damage to the amplifiers internal circuitry the amplifier should 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 switched AC power outlets to control or switch AC power to the amplifier Amplifier Rear Panel Power Connections UNBALANCED fj N E UNBALANCED INPUT WY WY INPUT RIGHT LEFT INPUT INPUT SELECT SELECT x fee ee eae MODEL 302 STEREO POWER AMPLIFIER MADE IN USA O Z A A A RIGHT n LEFT C A SPEAKER B SPEAKER casi p OUTPUT OUTPUT CAUTION ro PREVENT FIRE OR SHOCK HAZARD DO NOT TO RAIN OR R DO EXPO MOISTURE NO USER SERVICEABLE PARTS INSIDE REFER SERVICING TO QUALIFIED SERVICE PERSONNEL Dai ti RESET 5 A M P REFER TO OWNERS MANUAL BEFORE OPERATING Amplifier Rear Panel Power Connections Important Please strictly follow the following steps outlined below in order be
6. 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 repair facility or technician for servicing 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 incorporates a diamond tipped cutting tool This process was refined over many years to produce an artistic and attractive finish 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 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 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 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 Avery mild 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 th
7. c Range THD Noise 0 1W 500W 4 ohm CCIF Intermodulation Distortion 19 20 kHz Damping Factor 1kHz Overall Gain Balanced or Unbalanced Input Impedance Common Mode Rejection Ratio Absolute Phase Inputs Outputs Power Consumption Standby Switch OFF Standby Switch ON idle Maximum Amplifier Weight Shipping Container Dimensions Shipping Weight 300 watts 500 watts 5 Hz 60 kHz 3 dB gt 45 Amps 117 GBA lt 05 typically 006 1kHz lt 002 275 Selectable Internal Jumper 26 or 32 dB 40k ohms gt 900B 20 Hz 20 kHz Non inverting Pin 3 Positive User Selectable 2 x Balanced XLR 2 x Unbalanced RCA 2 Pairs Parallel Binding Posts per Channel 45 watts 55 watts 1200 watts 95 lbs 43 kg 27 Dx21 W x 16 Hy 68 cm L x 54 cm W x 41 cm 103 lbs 47 kg Dimensions A summary of the amplifier chassis dimensions is indicated below 18 3 in 46 9 cm E S A Le Le OI Le e v Y WO 7 GZ UlO OL 15 5 in 39 4 cm JEER ROWLAND WUD 6 9Z Ul 9 OL
8. e 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 panel small scratches from the use of any other agent to clean the front panel will become very visible 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 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 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 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 travel throughout an interconnected system Amplifier Installation Use and Care
9. efore be in perfect operating condition upon receipt If the amplifier does not operate correctly please notify your dealer immediately We strongly suggest that you save all packing materials Ifthe amplifier is returned to your dealer or Jeff 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 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 Contents 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 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 Owners Manual 6 One 1 Model 302 Stereo Power Amplifier Unpacking the Amplifier Unpacking the Amplifier The Model 302 is a large and heavy amplifie
10. er for further information about the use and configuration of this feature Constant 3V to 15V DC Signal 12VDC Typical Ground Detail of Mini plug Connector m Amplifier Rear Panel Signal Connections UNBALANCED f UNBALANCED INPUT WY INPUT RIGHT INPUT SELECT a 6 a Peas m ES O JEEE ROWLAND MODEL 302 STEREO POWER AMPLIFIER N A A A Le 2 L je z i 4 RIGHT A x Ly LEFT T OUTPUT 4 1200 W MAX ck Cs VOLTS AC DO NOT EXPOSE TO RAIN NO USER SERVICEABLE PARTS INSIDE REFER SERF ICING TO QUALIFIED SERVICE PERSONNEL OWNERS MANUAL BEFORE OPERATING Amplifier 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 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 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 inpu
11. fore operating your Model 302 Stereo Power Amplifier 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 Verify thatthe AC MAINS circuit breaker is closed no white area visible on breaker Install the AC Power Cable between the amplifier and your AC mains outlet 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 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 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 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 Connection requirements are illustrated below Please be aware that the remote feature simply places the amplifier in STANDBY mode and does not disconnectthe unit from power or AC mains Please contact your deal
12. h questions 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 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 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 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 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 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 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 c
13. hassis Be sure the amplifier is in STANDBY mode front panel indicator light OFF before connecting or disconnecting any loudspeaker or interconnect cables 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 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 issues to qualified personnel The voltages inside the Model 302 can be hazardous Amplifier Front Panel Functions and Indicators Front Panel Front Panel Power Standby Button Power Standby Indicator Amplifier 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 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 INDIC
14. osts from each channel to the high frequency terminals of your loudspeakers and one pair of each channel to the low 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 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 the warranty Internal 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 systems involving low efficiency loudspeakers may require the higher gain setting There is no sonic difference between the two settings 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 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 Model 302 Stereo Power Amplifier Specifications Output Power Continuous RMS watts both channels driven 8 ohms 4 ohms Power Bandwidth Peak Output Current Dynami
15. r 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 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 To unpack the amplifier Stand the shipping box vertically and open one end of both the inner and outer box Pull all box flaps back and turn the carton so that it is standing face down onto the open end Carefully lift both boxes up and off of the amplifier and packing material Remove the packing material cap from the upper end of the amplifier and untie the protective cloth bag Pullthe cloth bag back to expose the amplifier Lay the amplifier down on its feet Remove the remaining packing cap and the cloth bag The amplifier is now ready for installation Amplifier Maintenance Cleaning and Protection JEFF ROWLAND JEFF ROWLAND DESIGN GROUP Amplifier 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 need cleaning during the lifetime of the product All internal circuitry is self adjusting such that no
16. rial 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 Jeff Rowland Design Group PO Box 7231 Colorado Springs Colorado 80933 Tel 719 473 1881 Fax 719 633 4158 E mail rdg jeffrowiandcom Web www jeffrowland com Product 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 9996 Proprietary switch mode power supply technology ensures consistent performance under all operating conditions 12V
17. ts cannot be used for the same channel 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 the same time 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 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 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 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 fingers 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 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 yourloudspeakers are capable of bi wiring and you wish to do so simply connect one pair of binding p
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