Jeff Rowland Design Group 312 User's Manual
Contents
1. 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 E MAIL JRDG JEFFROWLAND COM 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 Zen Jeff Rowland President Jeff Rowland Design Group WWW JEFFROWLAND COM TELEPHONE 719 473 1181 PRODUCT FEATURES OWNER S MANUAL MODEL 312 STEREO AMPLIFIER e XLR input connectors for balanced system configuration e RCA input connectors for unbalanced system configurations e Dual Speaker Output Terminals on each channel for bi wiring applications e User selectable switching between balanced and unbalanced connections e Transformer coupled inputs provide universal compatibility with other components and eliminate ground loop noise and EMI e High efficiency ICEpower power conversion technology generates high output power with very little heat JEFF ROWLAND DESIGN GROUP 2007 ALL RIGHTS RESERVED e Full2. L JRDG JEFFROWLAND COM WWW JEFFROWLAND COM TELEPHONE 719 473 1181 INITIAL INSPECTION 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 Please Note Many shippers require notification and inspection within 24 hours of delivery to determine the nature of damages incurred 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 JEFF ROWLAND DESIGN GROUP 2007 ALL RIGHTS RESERVED UNPACKING The Model 312 is a large and heavy amplifier Due caution should be taken when unpacking and installing the amplifier to avoid in
3. OWNERS MANUAL MODEL 312 STEREO AMPLIFIER a Sa en TABLE OF CONTENTS OWNER S MANUAL MODEL 312 STEREO AMPLIFIER IntroOducCtiOn EE 2 Product Features een 3 Package Contents een 4 Initial Inspection een 5 Maintenance 8 Cleaninmg 6 Protection SYSTEMS er 7 JEFF ROWLAND DESIGN GROUP 2007 ALL RIGHTS RESERVED JEFF ROWLAND Installation Use amp Care 8 9 Signal amp Power Connections eese 10 13 SPECIFICATIONS eee 14 Par 1 EE 15 Optional Adjustments eee 16 INTRODUCTION OWNER S MANUAL MODEL 312 STEREO AMPLIFIER 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 2 PO BOX 7231 COLORADO SPRINGS COLORADO 80933 USA 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
4. TEREO AMPLIFIER D amp E LOUDSPEAKER OUTPUT Unscrew the knob that secures the speaker output connectors on both the LEFT SPEAKER OUTPUT E and the RIGHT SPEAKER OUTPUT D 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 and RIGHT CHANNEL Secure the loudspeaker connections by tightening the knob securely with your fingers The Model 312 will only accept spade terminations for loudspeaker cables Banana plugs or bare wire connections can be used but require an optional clamp available from your JRDG Dealer E MAIL JRDG JEFFROWLAND COM The Model 312 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 capable of bi wiring and you wish to do so remove the jumpers connecting the two sets of binding posts together on your loudspeakers Connect one pair of binding posts from each channel to the high frequency terminals of your loudspeakers and one pair from 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 ce
5. amplifier The default setting from the only however if you as an end user choose to attempt factory is 26 dB which is adequate for the majority of applications There is these adjustments yourself JADG cannot be held no sonic difference between the two settings liable for any damage that may occur to your Model 312 Stereo Amplifier because of your actions Further accessing the interior of your Model 312 by removing the bottom cover can expose you to dangerous poten tially lethal electrical voltages Thus JRDG cannot be held liable for any injury you may sustain should you undertake any of these adjustments yourself NOTE Do not attempt to remove the top cover to adjust the overall gain without explicit instruc tions from your dealer or JRDG 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 16 PO BOX 7231 COLORADO SPRINGS COLORADO 80933 USA E MAIL JRDG JEFFROWLAND COM WWW JEFFROWLAND COM TELEPHONE 719 473 1181 PO BOX 7231 COLORADO SPRINGS COLORADO 80933 USA E MAIL JRDG JEFFROWLAND COM WWW JEFFROWLAND COM TELEPHONE 719 473 1181
6. fier should not be disconnected from AC power without first placing the amplifier in Standby mode 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 or the AC mains power plug should be removed from the amplifier JEFF ROWLAND DESIGN GROUP 2007 ALL RIGHTS RESERVED EN G A BALANCED INPUTS If you are using balanced XLR interconnects from your preamplifier or source component position the INPUT SELECT switches B to BALANCED INPUT C UNBALANCED INPUTS If you are using unbalanced RCA intercon nects position the INPUT SELECT switches to UNBALANCED INPUT Connect the corresponding interconnect cables to either the BALANCED INPUTS A or UNBALANCED INPUTS C 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 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 inter connect 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 1 12 PO BOX 7231 COLORADO SPRINGS COLORADO 80933 USA SIGNAL amp POWER CONNECTIONS OWNER S MANUAL MODEL 312 S
7. ge to the output section of the amplifier JEFF ROWLAND DESIGN GROUP 2007 ALL RIGHTS RESERVED SIGNAL amp POWER CONNECTIONS OWNER S MANUAL MODEL 312 STEREO AMPLIFIER ra ABC NBALANCED INPUT NO RIGHT INPUT FE o JEFF BOWLA 1 MODEL 312 STERO POWER AMPLIFIER MADE IN USA O RIGHT LEFT Q A SPEAKER B A SPEAKER B OUTPUT 1200 W MAX OUTPUT VOLTS AC REMOTE ON OFF SERIAL NUMBER T0000 MAINS EET CAUTIQN TO PREVENT FIRE R SHOCK a a A HAZARD DO NOT REMOW COVER PS O DO NOT EXPOSE TO F IN OR MOISTURE REFER TO ONNERS kama l MANUAL BEFORE OPER ING E 10 PO BOX 7231 COLORADO SPRINGS COLORADO 80933 USA E MAIL JRDG JEFFROWLAND COM WWW JEFFROWLAND COM TELEPHONE 719 473 1181 Before attempting any system interconnection please familiarize yourself with the front panel control of the Model 312 Stereo Power Amplifier 1 FRONT PANEL STANDBY POWER BUTTON Press this button to operate the amplifier Press again to place the amplifier in Standby mode 2 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 reverts to power saving Standby mode NOTE All ON OFF power switching should be initiated ONLY with this button The ampli
8. jury 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 6 PO BOX 7231 COLORADO SPRINGS COLORADO 80933 USA MAINTENANCE amp CLEANING OWNER S MANUAL MODEL 312 STEREO AMPLIFIER 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 16 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 no
9. l electrical voltages 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 8 PO BOX 7231 COLORADO SPRINGS COLORADO 80933 USA E MAIL JRDG JEFFROWLAND COM WWW JEFFROWLAND COM TELEPHONE 719 473 1181 EN G The JRDG Model 312 Stereo e Do not expose the amplifier to e Be sure the amplifier is unplugged e The Model 312 is designed to per Amplifier ha
10. mended 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 AG mains power when the amplifier is not in use WARNING If the unit is plugged into a voltage different from the range listed on the back panel serious damage to internal circuitry will result and will void the warranty STEP 1 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 STEP 2 Verify that the AC MAINS circuit breaker is closed no white area visible on breaker STEP 3 Install the AC Power Cable between the amplifier and your AC mains outlet STEP 4 Connect the 12V Remote ON OFF Mini plug Connector if required 15 SPECIFICATIONS OWNERS MANUAL MODEL 312 STEREO AMPLIFIER Output Power Continuous RMS watts both channels driven Frequency Response Peak Output Current Dynamic Range Load Impedance Range Input Impedance THD Noise 0 1 watts 500 watts 4 ohms CCIF Intermodulation Distortion 19 20 kHz Damping Factor 1 kHz Overall Gain Balanced or Unbalanced Common Mode Rejection Ratio Absolute Phase Inputs Outputs Power Consumption Amplifier Weight Amplifier Shipping Weight Overall A
11. mplifier Dimensions H x W x D 14 PO BOX 7231 COLORADO SPRINGS COLORADO 80933 USA E MAIL JRDG JEFFROWLAND COM WWW JEFFROWLAND COM TELEPHONE 719 473 1181 500 watts 8 ohms 1000 watts 4 ohms per channel 5 Hz 45 kHz 3 dB 8 ohms 40 amps 120 dBa 2 ohms 16 ohms 40k ohms lt 0 1 Typically 01 1 kHz lt 002 gt 1000 Selectable Internal Jumper 26 or 32 dB gt 90 dB 20 Hz 20 kHz Non inverting Pin 2 Positive 2 Balanced XLR 2 Unbalanced RCA user selectable 2 pair Parallel Binding Posts per channel Idle 35 watts Maximum 2000 watts 70 Ibs 32 kg 83 Ibs 38 kg 10 5 x 15 5 x 18 3 267mm x 394mm x 465mm DIMENSIONS OWNER S MANUAL MODEL 312 STEREO AMPLIFIER DESIGN GROUP 15 5 in 394 mm ma JEFF ROWLAND DESIGN GAOUP YSZ Ul OL pzy Ul LOL mn 18 3 in 465 mm JEFF ROWLAND DESIGN GROUP 2007 ALL RIGHTS RESERVED 297 Ul GOL o 15 OPTIONAL ADJUSTMENTS OWNER S MANUAL MODEL 312 STEREO AMPLIFIER RISK OF ELECTRICAL SHOCK OVERALL GAIN ADJUSTMENT By removing the top cover the overall gain of the Model 312 Stereo Power WARNING The instructions in this section are Amplifier can be adjusted to either 26 dB or 32 dB via jumpers located on meant for qualified JRDG service personnel the rear panel circuit board inside the
12. o 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 JEFF ROWLAND Gug S i m NEIG A O US JEFF ROWLAND DESIGN GROUP 2007 ALL RIGHTS RESERVED PROTECTION SYSTEMS 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 INSTALLATION USE amp CARE OWNER S MANUAL MODEL 312 STEREO AMPLIFIER Locate the amplifier as close as possible to its final installation point RISK OF ELECTRICAL SHOCK Allow access to the rear panel for making connections 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 letha
13. rtain 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 Certain subwoofer speakers which derive signals from amplifier outputs will require additional circuitry to properly isolate the amplifier output Please contact JRDG before connecting these types of subwoofers WWW JEFFROWLAND COM TELEPHONE 719 473 1181 F 12V REMOTE TRIGGER A 1 8 3 5 mm mini plug connector is provided on the rear panel of the Model 312 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 See FIGURE 1 Constant 3v To 15 DC Signal 12VDC Typical tip Ground sleeve FIGURE 1 Detail of 12V remote trigger and mini plug connector requirements NOTE 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 NOTE The amplifier must be placed in Standby mode with the front panel button before the 12V remote trigger function can be activated JEFF ROWLAND DESIGN GROUP 2007 ALL RIGHTS RESERVED EN G NOTE Due to the exceptionally low power consumption rating of the Model 312 it is recom
14. s been designed to rain moisture or excessively from the AC mains wall plug front form optimally with no adjustments operate at the highest level of damp conditions panel indicator light OFF before or maintenance for the lifetime of the efficiency and performance in connecting or disconnecting any product Do not attempt to open the any normal operating situation The Model 312 Stereo Amplifier loudspeaker or interconnect cables bottom cover of the amplifier and however there are a few impor must not be modified in any way refer all service issues to qualified tant use and care principles other than according to official e When operating the Model 312 a personnel The voltages inside the that must be kept in mind when service bulletins from JRDG properly grounded AC receptacle Model 312 can be hazardous operating the amplifier Otherwise the factory warranty should be used A potential shock will be immediately voided hazard may result if the supplied 3 wire grounded AC cable ground e The Model 312 Stereo Power terminal is defeated or lifted or Amplifier can be operated at a the unit is connected to a 2 wire nominal 100 120 220 or 240 ungrounded AC outlet volts AC The amplifier must be configured for the correct AC input e The output terminals or loudspeaker voltage before operation or serious cables should never be shorted to damage will result each other or to any chassis surface Shorting of the outputs may result in dama
15. t 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 E MAIL JRDG JEFFROWLAND COM e Please allow the front panel which is coated with an automotive grade polyure thane finish 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 e 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 use of any other cleaning agent may permanently scratch the finish e The top cover sides and bottom are protected by a durable black anodized finish and can 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 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 WWW JEFFROWLAND COM TELEPHONE 719 473 1181 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 t
16. y balanced topology implemented in both input and output circuitry e Power Factor Correction PFC in power supply reduces AC line har monic noise pollution and increases AC line power utilization to 99 e Proprietary switch mode power supply technology ensures consistent performance under all operating conditions e 12V remote ON OFF remote power Switching via 1 8 jack on rear panel e Standby power mode reduces warm up time EN CE approved speaker output terminals require no tools for secure low resis tance connections e Fail safe operation provided by user resetable thermal circuit breaker located on rear panel e Quiet transient free operation during power ON OFF and input configuration switching e Selectable overall gain of 26 or 32 dB e Ultra low resonance structurally rigid chassis precision machined from a solid block of aircraft grade 6061 16 aluminum e 3 point self leveling chassis support PACKAGE CONTENTS OWNER S MANUAL MODEL 312 STEREO AMPLIFIER 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 DESIGN GROUP MODEL 312 STEREO AMPLIFIER OWNER S MANUAL WARRANTY CARD aa AC POWER CABLE COMPLIANT ISOLATION PADS 4 PO BOX 7231 COLORADO SPRINGS COLORADO 80933 USA E MAI
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