JEFF ROWLAND D E S I G N G R O U P Coherence Stereo Preamplifier Owner's Manual 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 preamplifiers. With its combination of industrial grade active and passive devices, precision electronic circuitry and accurately machined chassis components throughout, your Coherence Preamplifier will offer you many years of musically satisfying enjoyment. Owner's Manual. Please take a few moments to read the remainder of this Jeff Rowland Design Group, Inc. 2911 North Prospect Street Colorado Springs, CO 80907 Phone: 719/473-1181 Fax: 719/633-4158 A thorough understanding of the operational features will allow you to gain the maximum Please note that your Preamplifier must be performance and ease of use for which this Preamplifier was designed. used with its companion Power Supply. and also recorded below. The serial number of each component is located on the rear panel of each, The Preamplifier serial number begins with the letter C and the Power Supply serial Please include these numbers with any correspondence regarding your Coherence number begins with the letter D. Preamplifier. It has been my joy to create an audio component of enduring value which will reflect a higher ideal of It is my hope that these qualities will enrich your experience of ownership. musical and artistic expression. Enjoy the music! Jeff Rowland President Product Features Seven balanced XLR inputs per channel. Two balanced XLR main outputs per channel. Two balanced XLR record outputs per channel. One balanced XLR "bypass" input per channel for use in home theater installations. All inputs and outputs can be used with single-ended RCA terminated interconnects by using XLR/RCA adapters (one male stereo pair and one female stereo pair supplied). Independent Listen and Record functions on each input permit simultaneous listening and recording from any two selected inputs. Each input can be individually adjusted for R/L balance, mono/stereo, absolute phase, input impedance, and gain, exclusively independent of every other input. Individually adjusted input settings are automatically memorized and recalled when returning to that input. Built-in "pink noise" generator facilitates break-in of preamplifier components and interconnected associated components. Six-function hand-held IR remote control with separate IR sensor/ display unit for remote IR reception and volume level indication. Chassis and all chassis components precision machined from 6061 aluminum plate provide maximum mechanical resonance control. All operational functions are under microprocessor control. Within five milliseconds of any function selected, the microprocessor reverts to a non-clocking "sleep" mode which eliminates any possibility of digital noise contamination. Transformer-coupled inputs and main outputs provide maximum immunity from RF contamination and system ground loops and enhance compatibility with a wide variety of interconnected components. Power Supply Features Separate power supply provides a stable, low noise DC power source utilizing reliable, long-life sealed lead-calcium batteries. Microprocessor controlled charge-management system ensures optimum battery operation under all conditions. The microprocessor is normally in non-clocking "sleep" mode, except when servicing a short-term operational command. Two separate power supply outputs for powering additional companion units such as an optional phono equalizer. Front panel AC/DC mode switch disconnects AC power when DC mode (pure battery) operation is selected. Chassis and all chassis components precision machined from 6061 aluminum plate provide maximum mechanical resonance control. Introduction / Product Features Contents 1 8 4 2 6 3 5 7 9 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). Note: Many shippers require notification and an inspection within twenty-four (24) hours of delivery to ascertain the nature of damages incurred. Your Coherence Preamplifier has undergone extensive performance evaluations, listening tests, quality control inspections and a minimum seventy-two (72) hour burn-in period prior to shipment and should be in a perfect operational condition upon receipt. If the Preamplifier does not operate correctly, please notify your dealer immediately. We strongly suggest that you save all packing materials. If the Preamplifier is returned to your dealer or Jeff Rowland Design Group, the original packing materials must be used for shipment. 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 a Return Authorization number be issued by Jeff Rowland Design Group prior to shipment. 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 2 3 Remote sensor/display unit Handheld remote transmitter Remote sensor/display unit interconnect cable adapter (DB-25 male to RJ-11) Remote sensor/display unit interconnect cable Eight (8) compliant isolation interface supports Four (4) XLR/RCA adapters (one pair male input adapters and one pair female output adapters) AC power cable DC power cable One (1) warranty card (in some countries warranties are provided by the respective importer) 4 5 6 7 8 9 Initial Inspection / Contents Front Panel Function Controls C B LISTEN SELECT O GAIN H INPUT TERM. E MONO R PHASE E BYPASS N MUTE C E RECORD SELECT GAIN C E D F G H VOLUME LISTEN RECORD 1 2 3 4 5 6 7 BAL L CUT R JEFF ROWLAND D E S I G N G R O U P CHARGE LOW FULL MODE SELECT BATT MODE AC A Front Panel Function Controls Before attempting any system interconnection, please familiarize yourself with the front panel controls of the Coherence Preamplifier and Power Supply. The descriptions below refer to the numbers associated with the features in the diagram above. Any of the controls described below, when initiated, will be automatically stored in the microprocessor memory and will be recalled when the particular input is selected. For example, if Input 1 is selected and the gain is increased by 5dB with the Phase rocker switch activated, these settings are memorized and will be automatically recalled when returning to Input 1 after listening to other inputs. All functions are memorized with the exception of the volume control. However, if the Preamplifier is disconnected from the Power Supply, even momentarily, these memorized settings will be lost. Front Panel A MODE SELECT push button: Momentarily pressing this button switches D GAIN rocker switch: Momentarily pressing the upper section increases the gain of the selected Input by 0.5 dB to a limit of 20 dB higher than normal (0 dB) overall gain. For example, twelve (12) momentary presses will increase the gain by 6 dB. The GAIN lamp will momentarily illuminate each time the rocker switch is pressed. E GAIN rocker switch: Momentarily pressing the lower section decreases the gain of the selected Input by 0.5 dB to a limit of 20 dB lower than normal (0 dB) overall gain. For example, twelve (12) momentary presses will decrease the gain by 6 dB. The GAIN lamp will momentarily illuminate each time the rocker switch is pressed. INPUT TERM rocker switch: Momentarily pressing the upper section of the INPUT TERM rocker switch connects a 600 ohm terminating resistor across the inverting and non-inverting (positive and negative) contacts of the selected Input connector. The INPUT TERM lamp remains illuminated. Pressing the lower section of the INPUT TERM rocker switch disconnects the 600 ohm terminating resistor and the input impedance of the selected input reverts to 18,000 ohms. The INPUT TERM lamp is not illuminated. MONO rocker switch sums the Left and Right channel outputs into a monophonic signal output for the selected input. The MONO lamp remains illuminated. Pressing the lower section of the MONO rocker switch returns the selected Input's Left and Right channel outputs to normal stereo operation. The MONO lamp is not illuminated. F the power supply between AC and BATT operational modes. Either the BATT lamp or the AC lamp will be illuminated. Note: BATT mode is not allowed unless the batteries have achieved sufficient charge capacity. B LISTEN SELECT rocker switch: Momentarily pressing the upper section enables INPUT/RECORD buttons 1-7 for listening via the preamplifier Main output jacks. LISTEN SELECT lamp will remain illuminated unless the lower section Record Select rocker switch is pressed. C RECORD SELECT rocker switch: Momentarily pressing the lower G MONO rocker switch: Momentarily pressing the upper section of the section enables INPUT/RECORD buttons 1-7 for recording via the preamplifier Record output jacks. RECORD SELECT lamp will remain illuminated unless the upper section LISTEN SELECT rocker switch is pressed. H PHASE rocker switch: Momentarily pressing the upper section of the PHASE rocker switch inverts the absolute phase of both channels of the selected Input. The PHASE lamp remains illuminated. Pressing the lower section of the PHASE rocker switch restores normal polarity to both channels of the selected Input. The PHASE lamp is not illuminated. Function Controls continue on the next page. Front Panel Function Controls Front Panel Function Controls, (cont.) C LISTEN SELECT O GAIN H INPUT TERM. E MONO R PHASE E BYPASS N MUTE C E M RECORD SELECT GAIN I J VOLUME K LISTEN RECORD 1 2 3 4 5 6 7 BAL L CUT R L JEFF ROWLAND D E S I G N G R O U P CHARGE LOW FULL MODE SELECT BATT MODE AC Front Panel Function Controls, (cont.) I BYPASS rocker switch: Momentarily pressing the upper section of the BYPASS rocker switch enables the rear panel BYPASS inputs. The overall gain of the preamplifier remains fixed at 0 dB (unity) gain. All other preamplifier functions are disabled except for record functions. All previously selected front panel lamps are not illuminated with the exception of the BYPASS and selected RECORD input lamp. Pressing the lower section of the BYPASS rocker switch or selecting any other Listen input will restore normal operation. The previously selected LISTEN Input lamp is illuminated and the BYPASS lamp is not illuminated. MUTE rocker switch: Momentarily pressing the upper section of the MUTE rocker switch mutes the preamplifier outputs. The MUTE lamp illuminates. Pressing the lower section of the MUTE rocker switch restores the normal condition of the preamplifier outputs. The MUTE lamp is not illuminated. image is shifted to the left or right slightly for each press of the BAL L or BAL R button. Each press equals a total channel imbalance of 1 dB. For each 0.5 dB that one channel is offset, the opposite channel is offset in the opposite direction by 0.5 dB. This feature maintains that the absolute volume level will remain the same even though the image will be shifted by a specific amount. A total of six (6) presses on each button (3dB) can be achieved which will give a total imbalance of 6 dB between right and left channels. Either the L or R lamp will be illuminated to indicate a channel imbalance. Otherwise, neither L nor R lamp is illuminated. L CUT L/R push buttons: If the Mute lamp is illuminated, pressing the CUT L push button will mute the left channel only. The CUT L lamp illuminates. Conversely, if the Mute lamp is illuminated, pressing the CUT R push button will mute the right channel only and the CUT R lamp illuminates. To restore normal operation, press the lower section of the MUTE rocker switch. volume, while rotating the knob counterclockwise decreases volume. The VOLUME control provides a fixed range of 63.5 dB in increments of 0.5 dB throughout a rotation of 230 degrees. The 63.5 dB range remains constant, independent of the overall gain selected by the GAIN rocker switch mentioned above. The VOLUME control does not utilize mechanical end-stops to indicate minimum or maximum volume settings. The numerical position of the VOLUME control is indicated when the remote sensor/display unit is utilized. M VOLUME control: Rotating the VOLUME control clockwise increases J K BAL L/R push buttons: If the MUTE lamp is not illuminated, the stereo Front Panel Function Controls, (cont.) Preamplifier and Power Supply Rear Panels C C A D A D E B C B 3 2 2 1 Preamplifier Rear Panel A INPUTS 1-7 (Female XLR): Seven (7) XLR fully balanced or single- Power Supply Rear Panel 1 ended inputs (via supplied XLR/RCA adapters) are provided for line level signals only. Each INPUT connector conforms to a Pin # ...