Model 12 Model 12 Mono Power Amplifier Mono Power Amplifier Owner's Manual Owner's Manual Introduction W elcome 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. W ith its combination of features such as numerous function control and interconnect possibilities, precision electronic circuitry, and accurately machined chassis components throughout, your Model 12 Mono Power Amplifier will offer you many years of musically satisfying enjoyment. P lease 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 J eff Rowland Design Group, Inc. 2911 North Prospect Street Colorado Springs, CO 80907 T elephone: 719-473-1181 F ax: 719-633-4158 E -mail: jrdg@jeffrowland.com W eb: www.jeffrowland.com operational features will allow you to gain the maximum performance and ease of use for which this amplifier was designed. P lease note that your Model 12 Mono Amplifier serial number begins with the letter "F." 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 12 Mono Power Amplifier. I t has been my joy to create an audio component of enduring value that reflects a higher ideal 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 Product Features · XLR input connectors for balanced (Differential ModeTM) system configuration. · · · RCA input connectors for unbalanced system configurations. Selectable overall gain of 26 or 32 dB. User selectable switching between balanced and unbalanced connections. · · 12V remote ON/OFF power switching connector. Automatic temperature stabilizing circuitry maintains constant operating temperature. · CE approved speaker output connectors requiring no tools for tight connections. · Separate power supply featuring 2nd generation high-speed switch mode circuit design. · Parallel Balanced Input capability for multiple amplifier · · Automatic bias adjustment maintains optimal bias setting regardless of source material or loudspeaker load. · · Standby power condition reduces warm-up time. Fail-safe operation provided by user-resetable thermal circuit breakers located on power supply 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 ModeTM circuit topology implemented from input to output. Low resonance, structurally integrated chassis constructed of precision-machined aircraft grade aluminum. connection in high current demand situations. Features Contents Model 12 Amplifier Section Model 12 Power Supply DC Power Supply Cable AC Power Cable Warranty Card Initial Inspection 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 ascertain the nature of damages incurred. Your Model 12 Mono Power Amplifier has undergone extensive performance evaluations, listening 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 operate correctly, please notify your dealer immediately. We strongly suggest that you save all packing materials. If the amplifier is to be 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 E nsure 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. I nspect 1 One AC Power Cable 2 One DC Power Supply Cable 3 One Warranty Card (In some countries, warranties are provided by the respective importer.) Contents Care, Cleaning, and Maintenance Care T he Model 12 Mono 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 or exposed metal. 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 unit 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. A very 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 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 oilbased furniture wax or 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 treatment or cleaning of your Model 12 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. Maintenance A ll 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 or stable so no adjustments or maintenance of any kind should be necessary over a lifetime of normal operation. 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. It is not recommended that the customer attempt to disassemble or repair the unit and doing so may void your warranty. · Care Amplifier Front and Rear Panel Function Controls Amplifier Front Panel Standby/Power Button Power Indicator LED Amplifier Rear Panel Input Select Switch NEUTRIK NEUTRIK PUSH Amplifier Front and Rear Panel Function Controls Controls B efore attempting any system interconnection, please familiarize yourself with the front and rear panel controls of the Model 12 Mono Power Amplifier. The descriptions below refer to the diagrams above. Front Panel 1 FRONT PANEL STANDBY/POWER BUTTON: Press this button to Rear Panel (Note: If desired, the switch described below can be switched while the amplifier is operational and playing music.) operate the amplifier. Press again to place the amplifier in 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 and internal circuitry reverts to power-saving (Standby) mode. Anomalous operating conditions will place the amplifier in Standby mode and will prevent the amplifier from being switched back on again until such a condition is eliminated. To avoid spurious noises, the amplifier should never be turned 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 should never be disconnected from AC power without first placing the amplifier in Standby mode. 1 INPUT SELECT SWITCH: This switch selects either the unbalanced RCA inputs or the balanced XLR inputs. Note: When the RCA position is selected, pin 2 of the XLR is shorted to pin 1. Control Functions Rear Panel Power Connections Amplifier Rear Panel DC Power Supply Cable Connector NEUTRIK NEUTRIK PUSH Volts AC Indicator AC Power Cable Connector Power Supply Rear Panel Installation L ocate the amplifier as close as possible to its final installation point. Allow access to the rear panel for making connections. Rear Panel Power Connections Important: Please strictly follow the steps in order as outlined below before operating your Model 12 Mono Power Amplifier. The Model 12 Mono Power Amplifier is convection cooled, eliminating the need for fan or forced-air cooling. When operating, the chassis should have at least two (2) inches of air space around the heatsink areas. 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. 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. 2 Install the DC Power Supply Cable between the power supply and the amplifier section. There is a slot cut in the edge of the connector on each end of the cable, and this slot should be aligned to face up. Use the knurled ring on the connector to secure the cable to both the power supply and the amplifier. 3 Verify that the AC MAINS CIRCUIT BREAKER and the POSITIVE and NEGATIVE SUPPLY CIRCUIT BREAKERS are closed. mains outlet. 4 Install the AC Power Cable between the amplifier and your AC 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. Installation and Power Signal Connections and Remote Input Select Switch Amplifier Rear Panel Balanced Input Connector NEUTRIK NEUTRIK PUSH Parallel Input Connector Speaker Output 12V Remote Connector Power Supply Rear Panel Signal Connections and Remote T he Model 12 Mono Power Amplifier offers unprecedented (usually red) loudspeaker cable spade terminal to the positive (+) binding post and the negative spade terminal (usually black) to the negative (-) binding post. Secure the loudspeaker connection by tightening the knob securely with your fingers. compatibility with associated audio components. When Connecting or disconnecting speaker or interconnect cables, it is necessary 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 + Warning: Both positive and negative outputs are electrically 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. INPUT or UNBALANCED INPUT. 2 Connect your interconnect cable to one input ­ either BALANCED 3 The PARALLEL BALANCED INPUT connector is for secondary 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 can result in damage to the amplifier and will void the warranty. components requiring a parallel input signal. The output from this connector is identical to the signal at the BALANCED INPUT. This connector should be used for applications such as driving a secondary amplifier for bi- or tri-amplification purposes or a powered subwoofer. For parallel connection instructions, please see the following two pages of this manual. 12V Remote 1 A 12V REMOTE ON/OFF mini-plug connector is provided on the Note: This connection should not be used ...