Coherence Manual art - Jeff Rowland Design Group

Coherence Manual art - Jeff Rowland Design Group
JEFF ROWLAND
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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.
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With its combination of industrial grade active and passive devices,
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Jeff Rowland Design Group, Inc.
2911 North Prospect Street
precision electronic circuitry and accurately machined chassis components throughout, your Coherence Preamplifier will
Colorado Springs, CO 80907
offer you many years of musically satisfying enjoyment.
Phone: 719/473-1181
Owner’s Manual.
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Please take a few moments to read the remainder of this
A thorough understanding of the operational features will allow you to gain the maximum
performance and ease of use for which this Preamplifier was designed.
used with its companion Power Supply.
and also recorded below.
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Jeff Rowland
President
The serial number of each component is located on the rear panel of each,
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Please include these numbers with any correspondence regarding your Coherence
It has been my joy to create an audio component of enduring value which will reflect a higher ideal of
musical and artistic expression.
Enjoy the music!
Please note that your Preamplifier must be
The Preamplifier serial number begins with the letter C and the Power Supply serial
number begins with the letter D.
Preamplifier.
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It is my hope that these qualities will enrich your experience of ownership.
Fax: 719/633-4158
Product Features
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Seven balanced XLR inputs per channel.
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Two balanced XLR main outputs per channel.
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Two balanced XLR record outputs per channel.
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One balanced XLR “bypass” input per channel for use in home theater
installations.
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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).
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Independent Listen and Record functions on each input permit
simultaneous listening and recording from any two selected inputs.
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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.
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Built-in “pink noise” generator facilitates break-in of preamplifier
components and interconnected associated components.
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Six-function hand-held IR remote control with separate IR sensor/
display unit for remote IR reception and volume level indication.
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Chassis and all chassis components precision machined from 6061
aluminum plate provide maximum mechanical resonance control.
Introduction / Product Features
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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.
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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
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Separate power supply provides a stable, low noise DC power source
utilizing reliable, long-life sealed lead-calcium batteries.
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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.
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Two separate power supply outputs for powering additional
companion units such as an optional phono equalizer.
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Front panel AC/DC mode switch disconnects AC power when DC
mode (pure battery) operation is selected.
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Chassis and all chassis components precision machined from 6061
aluminum plate provide maximum mechanical resonance control.
Contents
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4
2
6
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7
5
9
Initial Inspection
Contents
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.
Ensure that all of the auxiliary components listed below are enclosed
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.
1
Remote sensor/display unit
2
Handheld remote transmitter
3
Remote sensor/display unit interconnect cable adapter
(DB-25 male to RJ-11)
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.
4
Remote sensor/display unit interconnect cable
5
Eight (8) compliant isolation interface supports
6
Four (4) XLR/RCA adapters (one pair male input adapters and one
pair female output adapters)
7
AC power cable
8
DC power cable
9
One (1) warranty card (in some countries warranties are provided by
the respective importer)
Initial Inspection / Contents
within the accessory box. Refer to the diagrams illustrated above and
verify the components included.
Front Panel Function Controls
B
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LISTEN SELECT
GAIN Õ
INPUT TERM.
MONO
PHASE
BYPASS
MUTE
RECORD SELECT
GAIN Ô
C
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D
F
C
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G
VOLUME
LISTEN
RECORD
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JEFF ROWLAND
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CHARGE
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BATT
MODE SELECT
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BAL
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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
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
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.
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.
F
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.
G MONO rocker switch: Momentarily pressing the upper section of the
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.
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.)
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LISTEN SELECT
GAIN Õ
INPUT TERM.
MONO
PHASE
BYPASS
MUTE
C
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RECORD SELECT
GAIN Ô
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VOLUME
LISTEN
RECORD
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7
BAL
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CUT
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JEFF ROWLAND
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Front Panel Function Controls, (cont.)
I
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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.
K BAL L/R push buttons: If the MUTE lamp is not illuminated, the stereo
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.
Front Panel Function Controls, (cont.)
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.
M VOLUME control: Rotating the VOLUME control clockwise increases
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.
Preamplifier and Power Supply Rear Panels
C
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D
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B
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Preamplifier Rear Panel
Power Supply Rear Panel
A INPUTS 1-7 (Female XLR): Seven (7) XLR fully balanced or single-
1
RS232 DATA IN/OUT (DB-25 female connector): Provides power and
signal data to the remote sensor/display unit.
2
POWER SUPPLY OUTPUTS A & B (XLR female connectors): Parallel DC
power and signal data outputs for preamplifier and optional companion
units such as phono equalizer, etc.
3
AC POWER INLET: Verify that the voltage indicated on the rear panel
corresponds to the AC mains of your service area.
ended inputs (via supplied XLR/RCA adapters) are provided for line
level signals only. Each INPUT connector conforms to a Pin #1 ground,
Pin #2 negative, Pin # 3 positive standard. Both positive and negative
terminals of each INPUT connector are isolated from ground by several
megohms which eliminates the possibility of ground loops and restores
maximum common mode rejection ratio.
B BYPASS INPUT (Female XLR): Accepts balanced or single-ended inputs
(via supplied XLR/RCA adapters) from home theater surround processor
front left and front right outputs.
C MAIN OUTPUTS 1 & 2 (male XLR): Provides parallel XLR fully balanced
or single-ended outputs (via supplied XLR/RCA adapters). Each OUTPUT
connector conforms to a Pin #1 ground, Pin #2 negative, Pin #3 positive
standard. Both positive and negative terminals of each OUTPUT connector are isolated from ground by several megohms which eliminates the
possibility of ground loops and restores maximum common mode
rejection ratio. Balanced output signals are always provided regardless of
input (single-ended or balanced) signal configuration.
D REC OUTPUTS 1 & 2 (male XLR): Provides parallel XLR fully balanced
or single-ended outputs (via supplied XLR/RCA adapters). Each OUTPUT
connector conforms to a Pin #1 ground, Pin #2 negative, Pin #3 positive
standard. REC OUTPUTS are ground referenced and buffered from any
selected input. Balanced output signals are always provided regardless of
input (single-ended or balanced) signal configuration.
E
POWER SUPPLY INPUT (male XLR): Interconnects the Preamplifier to
the Power Supply via the supplied DC power cable. Caution: Use only
the supplied DC power cable and companion Power Supply.
Preamplifier and Power Supply Rear Panels
Installation and Operation
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LISTEN SELECT
GAIN Õ
INPUT TERM.
MONO
PHASE
BYPASS
MUTE
RECORD SELECT
GAIN Ô
C
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VOLUME
LISTEN
RECORD
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Installation and Operation
The Preamplifier is normally installed directly on top of the companion
Power Supply. Be sure to install the supplied compliant isolation interface
supports between each unit and underneath the Power Supply to avoid
damage to chassis components and provide maximum mechanical isolation and decoupling from the supporting structure.
First, connect the supplied DC Power Cable (1) between the Preamplifier
and Power Supply, as illustrated above. Then connect the AC mains to the
Power Supply using the supplied AC Power Cable. If desired, the
Preamplifier can be located up to twenty (20) inches (one half (0.5) meter)
above or below the power supply. The use of a longer DC power cable
offering greater separation distance is not recommended.
Upon initially connecting AC power, it may be necessary to press and hold
down the MODE button (2) for five (5) seconds to initially boot-up or
reset the charge management system located within the Power Supply. In
a few seconds, the AC mode lamp will light and the Preamplifier INPUT 1
And RECORD 1 lamps will illuminate.
The Coherence Preamplifier is designed to be powered from the AC mains
which automatically initiates battery charging as necessary and is indicated
by the illumination of the AC mode lamp. However, the Preamplifier is still
powered by the internal batteries. AC mains power is disconnected from
the power supply internally whenever the BATT mode is selected using
the MODE push button. Under this operating condition, the preamplifier
operates exclusively from the internal batteries. Up to fifteen (15) hours of
operation in this mode is possible depending upon the initial state of
charge of the internal batteries.
If the Preamplifier is not used for an extended period of time and/or a
source of AC power will not be available, AC power should be removed
and the MODE push button should be pressed and held down for
approximately five seconds. A slight click will be heard. No lamps should
be illuminated. This feature allows the preamplifier to be stored or
shipped without discharging the internal batteries.
Installation and Operation
If the FULL charge lamp is illuminated, the battery capacity will range
between 50-100% of full charge. This lamp will not illuminate shortly after
the BATT mode is selected.
If the LOW charge lamp is illuminated, the battery is significantly
discharged and will automatically switch back to AC mode to commence
charging. If AC mains power is not available under these conditions, then
the Power Supply will automatically switch off, thus preventing the
batteries from becoming overly discharged.
The Power Supply is intended to operate connected to active AC mains at
all times. The charge management system only permits operation at the
voltage indicated on the rear panel. If an incorrect AC line voltage is used,
all of the Power Supply front panel lamps will flash on and off simultaneously approximately four times per second.
The Preamplifier is equipped with an internal pink noise generator. This
noise is intended for cable, component and loudspeaker break-in. The
noise generated is out of phase between left and right channels. A distinct
acoustic null should become apparent at a midway point between the two
speakers when utilizing this function.
To initiate the internal pink noise generator, press the upper section of the
MUTE rocker switch (3) and then the lower section of the BYPASS rocker
switch (4). The Preamplifier will automatically route pink noise throughout
the Preamplifier circuitry for break-in purposes. The volume control can be
used to adjust the volume of pink noise at the output jacks as desired. To
resume normal operation, simply select any LISTEN input (5).
The Coherence Preamplifier utilizes circuit technologies which require a
much longer “break-in” period than other preamplifier designs. It is
recommended that a period of at least eight (8) days (200 hours) of
continuous operation be allowed before full sonic performance potential
can be expected.
Remote Control Features
A The six-function, hand-held, IR remote transmitter permits remote
operation of Input Selection, Volume Up/Down, Balance L/R and
Mute functions
B A separate remote sensor/display unit simultaneously receives
transmitted data and displays the numerical Volume control position
from 0 to 63.5 dB in increments of 0.5 dB.
C The supplied RJ-11 cable allows the remote sensor/display unit to be
placed within two meters of the preamplifier for optimal IR reception
and/or volume control position viewing. Up to 30 meters of cable
length can be used if desired.
D The Interconnect Cable Adapter should first be connected securely to
the DB-25 connector on the rear panel of the Power Supply using the
integral finger screws. The RJ-11 cable can then be installed from the
Remote Sensor/Display unit to the adapter.
After installing the remote sensor/display unit and associated connecting
cable, reset the preamplifier by pressing the power supply MODE
switch and holding it for at least 5 seconds. Then release to commence
operation.
The remote transmitter handset operates on a standard 9 volt battery
available from a wide variety of sources. This battery is accessed by
removing the two Phillips head screws on the back side of the handset.
D
Four (4) different data rate transmission codes can be selected if interference from other IR remote transmitters become an issue. Simply match
the switch code between both handset and remote receiver/display unit
internal switches (accessed by removing the respective bottom covers).
B
C
A
Coherence Performance Specifications
Overall Gain
Adjustable for each input ±20 dB relative
to unity gain (0 dB) in 0.5 dB increments
Input Impedance
Adjustable for each input
18k or 600 ohms
18k or 600 ohms
Unbalanced
Balanced
Power Supply Specifications
Power Consumption
40 watts maximum, 10 watts nominal
Mains Voltage
100V, 120V, 220V, 240V, 50/60 Hz
Battery Complement
2 each 12 volt, 7.2 amp/hour
user replaceable sealed, lead calcium,
maintenance-free batteries
Battery Service Life
5-8 years
Output Impedance
Unbalanced
Balanced
50 ohms
50 ohms
Maximum Input Level
13 volts RMS at 0 dB gain
Maximum Output Level
13 volts RMS (24 dBm)
Dimensions
17.5 in W x 11.2 in D x 3.7 in H
44.5 cm W x 28.4 cm D x 9.40 cm H
Output Noise Level
12 microvolts
20-20 KHz bandwidth, 0 dB gain
Weight
43 lbs (19.5 kg)
AC Unassisted Run Time 14-18 hours based upon
Signal To Noise Ratio
Greater than 96 dB
Channel Separation
Greater than 110 dB, @ 20-20 KHz
bandwidth
Frequency Response
5 Hz-160 KHz, -3 dB
THD + Noise
0.0016% 10 volt output, 600 ohm load
Gain Range
63.5 dB, 127 equal increments
Gain Resolution
0.5 dB ± 0.03 dB over entire range
Channel Balance
± 0.03 dB throughout entire range
Dimensions
17.5 in W x 12.0 in D x 3.7 in H
44.5 cm W x 30.9 cm D x 9.40 cm H
Weight
40 lbs (18 kg)
initial battery full charge
Because Jeff Rowland Design Group is constantly analyzing new
design improvements, we reserve the right to change or modify product
specifications without notice or obligation.
If you have any additional questions regarding installation or operation,
please contact your authorized Jeff Rowland Design Group Dealer.
JEFF ROWLAND
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