Jeff Rowland Design Group 112 User's Manual
Contents
1. waranties are provided by the respective importer C a re Cleanin and Maintenance Care The Model 112 Stereo Power Amplifier is finely constructed from pieces of solid aluminum The surface of the unit is cut in a unique process that uses a diamond tipped blade This process was refined over many years to produce an artistic and attractive finish The front top bottom and side panels are then finished with fine automobile polyurethane clear coat after a light anodizing to preserve the clarity of the finish and are not raw orexposed metal Because the surface is not finished in the typical fashion of most audio and video equipment there are a few tules that must be kept in mind when cleaning the equipment e Please allow the unit to cure for 6 months before attempting to clean it This will prevent small scratches from maning the surface before the surface coating hashad a chance to harden completely e The top cover sides and bottom covercan all be cleaned with a soft cotton cloth such as an optical lens cleaning cloth orfine fumiture 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 A very mild plastic or glass cleaner that does not contain ammonia should be tied only asa last resort Please contact the factor2. 633 4158 E mail jdgojeffrowiand com Web wwv jeffrowland com XLR input connectors for balanced Differential Mode system configuration RCA input Connectors forunbalanced system configurations Selectable overall gain of 26 or 32 dB User selectable switching between balanced and unbalanced connections 12V remote ON OFF power switc hing connector Automatic temperature stabilizing circuitry maintains constant operating temperature CE approved speaker output connectors requiring no tools for tight connections Automatic bias adjustment maintains optimal bias setting regardless of source material orloudspeaker load Features Product Features Standby power condition reduces warm up time Fail safe operation provided by userresetable thermal circuit breakers located on rear panel Quiet transient free operation during power and function mode switching Automatic input muting under anomalous input or output operating conditions Fully balanced Differential Mode circuit topology implemented from input to output Low resonance stucturally integrated chassis constructed of precision machined aircraft grade aluminum Contents gt JEFF ROWLAND DESIGN GROUP S Model 112 Stereo Power Amplifier WARRANTY REGISTRATIQN JEFF ROWLAND DESIGN GROUP AC PowerCable
3. Warranty Card Initial Inspection Inspect the shipping container for damage If the shipping container packing material amplifier oraccessories 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 twentyfour hours of delivery to determine the nature of damages incurred Your Model 112 Stereo Power Amplifier has undergone extensive performance evaluations listening tests quality control inspections and a minimum seventy two hour bum in period prior to shipment and should therefore be in perfectoperating condition upon recejpt If the amplifier does not operate correctly please notify your dealer immediately We strongly suggest that you save all packing materials If the amplifier is to be retumed to your dealer or J eff Rowland Design Group the original packing materials must be used for shipment to avoid damage Neither eff Rowand Design Group nor the shipper can be held responsible for damages incured during transit if the Original factory packing is not used All factory retums require that Jeff Rowland Design Group issue a Retum Authorization RA number priorto shipment Contents Contents Ensure that all of the auxiliary components listed below are enclosed within the accessory box Refer to the diagrams illustrated above and verify the components included 1 OneAC PowerCable 2 One Waranty Card In some counties
4. have the remain ON amplifier reconfigured for the proper AC mains voltage Abnomal operation of amplifier intemal circ uitry Contact your dealer immediately 50 60 Hz buzz noise in loudspeakers Ground loop condition created between Use balanced system configuration if possible components in system Inspect interconnect cables for poor connection or termination Additional Information If you have any additional questions regarding the installation or operation of the Model 112 Stereo Power Amplifier please contact your authorized J eff Rowland Design Group dealerorcheckthe J eff Rowland Design Group web site at http www jeffrowland com Troubleshooting Post Office Box 7231 Colorado Springs Colorado 80933 USA
5. selected pin 2 of the XLR is shorted to pin 1 Standby mode and will prevent the amplifier from being switched backon again until such a condition is eliminated To avoid spurious noises the amplifier should never be tumed on if the inputs on the rear panel are not connected Note All ON OFF power switching should be initiated ONLY with this button The amplifier snould never be disconnected from AC power without first placing the amplifier in Standby mode Control a eet Rear Panel Power Connections Amplifier Rear Panel UNBALANCED M E INPUT ee RIGHT MODEL 112 SELECT STEREO POWER AMPLIFIER JUTPUT MADE IN U S A PUSH TO RESET PUSH TO RESET SERIAL II j l E N NUMBER M o P LOOOO FUSE POS SUPPLY GDC 3 0A 200 2 VOLTS AC POS SUPPLY GDC 6 3A 10 20 V 50 60 Hz AC Power Cable Volts AC Connector Indicator Installation Locate the amplifier as close as possible to its final installation point Allow access to the rear panel formaking connections The Model 112 Stereo Power Amplifier is convection cooled eliminating the need forfan orforced air cooling When operating the chassis should have at least two 2 inches of air space around the heatsink areas Multiple units can be stacked vertically facilitating an upward flow of wam 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 Re
6. Model 112 Stereo Power Amplifier Owner s Manual Introduction Welcome to the J eff 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 circuity and accurately machined chassis components throughout your Model 112 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 112 Stereo Amplifier serial number begins with the letter L This number is recorded below and is also located on the rear panel of the chassis Please include this number with any conespondence regarding your Model 112 Stereo Amplifier It has been my joy to create an audio component of enduring value that reflects a higher ideal of musical and artistic expression Itis my hope that these qualities will enrich your experience of ownership Enjoy the music J eff Rowland President J eff Rowland Design Group J eff Rowland Design Group Inc 2911 North Prospect Steet Colorado Springs CO 80907 Telephone 719 473 1181 Fax 719
7. ar Panel Power Connections Important Please strictly follow the steps in order as outlined below before operating your Model 112 Stereo Power Amplifier 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 amplifierto AC powerand contact your dealer immediately 2 Verify that the AC MAINS CIRCUIT BREAKER and the POSITIVE and NEGATIVE SUPPLY CIRC UIT BREAKERS are closed 3 Install the AC Power Cable between the amplifier and your AC mains outlet Note If the amplifier is to be moved to another location always place the unit in Standby mode before disconnecting the AC power cable from the AC mains wall outlet Insta lla tio n and Dawar Signal Connections and Remote Input Select Unbalanced Switch Amplifier Rear Panel Input Connector ee E JEEF ROWLAND RIGHT MODEL 112 SELECT STEREO POWER AMPLIFIER MADE IN U S A REMOTE ON OFF 12v PUSH TO RESET PUSH TO RESET SERIAL E one A WOR NUMBER E 5 w a M m y LO000 FUSE POS SUPPLY GDC 3 0 A 200 240 V VOLTS AC POS SUPPLY GDC 6 3 A 100 120 V 50 60 Hz Balanced Input 12V Remote Speaker Connector Connector Output Signal Connections The Model 112 Stereo Power Amplifier offers unprecedented compatibility with associated audio components When Connecting or disconnecting speaker or interconnect cables it is necessa
8. circuitry could damage your loudspeakers and is equipped with a circuit that protects the amplifier fom DC current emitted by source components This system also prevents amplification of DC cuments that can damage your loudspeakers Do not alter the settings of the DC protection circuit as this will disable the ability of the amplifier to protect your loudspeakers These settings are for production and testing purposes only Because of the potentially dangerous voltages inside the chassis do not attempt to disassemble the amplifier Model 112 Stereo Power Amplifier Specifications Output Power Continuous RMS watts 8 ohms 4 ohms Power Bandwidth Slew Rate THD Noise Damping Factor Gain 1 watt 8 ohms Input Impedance Common Mode Rejection Ratio Absolute Phase 150 watts 275 watts DC to 160 kHz 3 dB 30 volts microsecond lt 008 gt 60 20 to 20 kHz User Selectable Intemal J umper 26 dBor32 dB 40k ohms gt 80 dB 20 20 kHz Phase Inverted Power Supply Power Consumption Inputs Outputs Dimensions Weight Shipping Dimensions Shipping Weight 500 VA toroidal transformer with 100 000 MFD total storage capacitance Regulated front end supply 75 watts idle 700 watts maximum Both Channels Driven Simultaneously at Full Output Power UserSelectable 2 xBalanced XLR 2 xUnbalanced RCA One Pair Binding Posts per Channel 17 5 Wx 11 7 D x 5 2 H 44 5
9. cm Wx33 5cm Dx 14 5cm H 55 lbs 24 5 kg 24 Wx22 D x13 H 61cm Wx56cm D x33cm H 65 lbs 29 4 kg Internal Control Basic Troubleshooting A summary of fault conditions and their causes and remedies are listed below The Model 112 Stereo Power Amplifier can produce high power levels that without well designed protection circuitry could damage loudspeakers Therefore most fault conditions will result in the Model 10 reverting into Standby Mode Condition Cause Remedy Front panel POWER INDICATOR LED does not Incomect power connections incomect speaker Reset circuit breaker review Installation and Rear illuminate after pressing POWER SIANDBY BUTTON connections or circuit breaker must be reset Panel Connections section of Owners Manual amplifier does not operate normally Abnomal Operation of the Model 112 intemal Contact your dealer immediately Circuitry FRONT PANEL SIANDBY POWER button reverts to Excessive sub sonic or DC signals produced by Repairor replace source component Identify and Standby Mode during listening but can be retumed source components corect abnomal conditions such as low frequency to normal operation rumble and or acoustic feedback caused by phono playback if applicable Severe clipping of amplifier circuitry Reduce volume slightly or use higher efficiency loudspeakers AC MAINS CIRC UT BREAKER switches OFF or will not AC mains voltage too high for amplifier Consult your dealer immediately to
10. ions Failure to avoid these precautions can result in damage to the amplifier and will void the warranty Remote 1 A 12V REMOTE ON OFF mini plug connector is provided on the rear panel of the power supply for remotely switching the amplifier between Operational and Standby modes The connections on this connector parallel the electrical contacts of the FRONT PANEL STANDY POWER button When connected to another component with the proper circuitry the amplifier can be tumed ON and OFF remotely Please contact your dealer for further information about this feature Signal amp 12V Internal Function Controls Overall Gain The overall gain of the Model 112 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 in a small number of situations involving low efficiency systems the higher gain setting may be necessary 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 DC Protection System The Model 112 Stereo Power Amplifier can produce high power levels that without well designed protection
11. ry to place the amplifier in Standby mode orange POWER INDICATOR LED on the front panel OFF 1 If you are using balanced XLR interconnects from your preamplifier or source component position the INPUT SELECT switch to BALANCED INPUT If you are using unbalanced RCA interconnects position the INPUT SELECT switch to UNBALANCED INPUT 2 Connect your interconnect cable to one input either BALANCED INPUTS or UNBALANCED INPUTS on each channel 3 Aslight 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 4 Unscrewthe knob that secures the speaker output connectors on both the LEFT SPEAKER OUTPUT and the RIGHT SPEAKER OUTPUT 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 YA 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 demonstrat
12. t to disassemble or repair the unit and doing so may void your waranty Amplifier Front and Rear Panel Function Controls a E JEFF ROWLAND DESIGN GROUP Power Indicator LED UNBALANCED INPUT JEFF ROWLAND DESIGN GROUP MODEL 112 STEREO POWER AMPLIFIER MADE IN U S A REMOTE ON OFF 12V PUSH TO RESET SERIAL m X NUMBEJ E LO006 FUSE GDC 3 0A 200 240V VOLTS AC GDC 6 3 A 100 120V 50 60 Hz Right Channel Input Left Channel Input Select Switch Select Switch Amplifier Front and Rear Panel Function Controls Before attempting any system interconnection please familiarize yourself with the front and rear panel controls of the Model 112 Stereo Power Amplifier The descriptions below referto the diagrams above Front Panel RearPanel 1 FRONT PANEL STANDBY POWER BUTION Press this button to Note If desired the switch described below can be switched while operate the amplifier Press again to place the amplifier in the amplifier is operational and playing music Standby mode The small orange POWER INDICATOR LED will illuminate when the amplifier is operational When the POWER INDICATOR LED is not illuminated all amplifier inputs are muted 1 INPUT SELECT SWITCH This switch selects either the unbalanced and intemal circuitry reverts to power saving Standby mode RCA inputs or the balanced XLR inputs Note When the RCA Anomalous operating conditions will place the amplifier in position is
13. y before trying any type of cleanser on the chassis other than water to clean the unit 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 Care based fumiture 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 Again the water or polish should be applied to the cloth not the chassis If you have any questions about the teatment or cleaning of your Model 112 amplifier please contact your dealer or the J eff 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 Maintenance 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 intemal circuitry is self adjusting or stable so no adjustments or maintenance of any kind should be necessary overa lifetime of normal operation If the amplifier is ever in need of service updating or upgrading it should only be retumed to an authorized repair facility or technician for servicing It is not ecommended that the customer attemp
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