Jeff Rowland Consonance Pre Owners manual

CONSONANCE PREAMPLIFIER

OWNER’S MANUAL

TABLE OF CONTENTS

Introduction
Initial Inspection
Features
Installation
Input Impedance Adjustments
Preamplifier Internal View
Impedance Adjustment Diagram
Overall Gain Adjustments
Gain Adjustment Diagram
Control Instructions
Remote Operation
Technical Specifications

Introduction

Congratulations on your purchase of what is unquestionably one of the finest analog
preamplifiers available today. With its combination of features such as full function
remote control, balanced outputs and state of the art circuitry, your Consonance
Preamplifier will give you many years of trouble free, top quality performance and
enjoyment.

Please take a few moments to read this owner’s manual. The Consonance offers a large
number of interconnect and user operational possibilities. A thorough understanding of
these features will allow you to gain the maximum performance for which this
preamplifier was designed.

The Consonance Preamplifier’s serial number begins with the letter A and is followed by
a four digit number. The serial number is located on the left side of the back panel. All
correspondence with your dealer or Jeff Rowland Design Group concerning this
preamplifier should include the serial number.

For any additional information or assistance, contact your dealer or the Jeff Rowland
Design Group factory.

Initial Inspection

Inspect the shipping container for damage. If the shipping container or packing material
is damaged, it should be kept until the contents of the container have been checked for
completeness and the preamplifier has been inspected both mechanically and
electrically. This preamplifier was fully tested and carefully inspected before shipment. It
should be free of any exterior defects and in perfect operational order upon receipt.

If there is any damage or defect or if the preamplifier does not operate correctly, notify
your dealer immediately. If the shipping container is damaged or the packing material
shows signs of stress, notify the shipper and Jeff Rowland Design Group. Keep the
shipping material for the shipper’s inspection.

In the shipping box you will find:

• AC power cord

• replacement fuses

• infrared remote control transmitter

• infrared remote control receiver and interconnect cable

• warranty card (This form must be completed and returned to JEFF ROWLAND

DESIGN GROUP [or its authorized distributor if outside the U.S.A.] within 14
days of purchase. Not only will your preamplifier be registered, but you will, in
the future, be notified of possible design updates, improvements and new
products.)

We strongly suggest that you save all packing materials

Features

• Six line inputs, the first of which can be used as an optional phono input

• Balanced outputs, in both RCA and XLR connector configurations

• Regulated power supply with toroidal transformer

• Microprocessor-controlled volume and switching

• A digitally-controlled resistor matrix volume control provides 200 precise, individual
steps

• User-stored level settings for all six inputs allow immediate recall of a "normal" level
for each source

• Dual-rate attenuator adjustment controls provide efficient volume control adjustments

• Fluorescent front panel display indicates operational status of the preamplifier under
all ambient lighting conditions

• User controlled display shut-off

• Infrared remote control of all preamplifier operational functions

• Separate remote receiver permits remote operation of preamplifier from a distant
location

• Image shift control (instead of channel balance trim) maintains overall volume level
while shifting stereo image left or right

• Mono and left or right channel cut functions

• Main outputs are muted temporarily during initial A/C power up, power drop or power
interruption

• All signal amplification utilizes high-current, Class A, solid-state technology

• All inputs and outputs are direct-coupled, thus eliminating the effects of capacitors in
the signal path.

• Independent power supply regulators are located at each stage of each amplifier
channel

• Mil-spec circuit board material, with oxygen-free copper traces and high- temperature
mask, provides superior electrical characteristics and long term protection against
adverse climatic conditions

• All signal switching is accomplished with hermetically sealed, gold-clad silver contact
signal relays

• All critical circuitry is encapsulated in a thermally-conductive epoxy to ensure excellent
thermal stability, mechanical integrity and ease of service

• Ability to drive any length of interconnect cable into a balanced 600 ohm load

• Adjustable input and output impedance minimizes source, load and cable interactions
in any application

Installation

Place the preamplifier as close as possible to its final installation point. If possible, allow
easy access to the back panel for making signal and power connections. The preamplifier
should be placed at a sufficient distance from other audio components such that there
will be no interference from stray electromagnetic fields.

The preamplifier is equipped with a power switch located and identified on the rear
panel. The power switch should be turned on after plugging the A/C power cord into the
A/C mains socket located on the back of the preamp. After turning on the preamplifier,
there will be a two second delay, and then the words "THE CONSONANCE" will be
displayed. Immediately thereafter, the display will indicate either "PHONO EQUIPPED" or
"PHONO DELETED" depending upon whether or not a phono module has been installed
within the preamplifier. The display will then switch to its normal status-indicator format.
Your preamplifier is now fully stable and will accept commands.

The rear panel power switch should be left on at all times, thereby maintaining stable
operating parameters and thereby improving performance, reliability and longevity.
Power consumption in stand-by mode is less than 30 watts, providing low-cost
operation.

Your Consonance is equipped with an infrared remote control receiver box which can be
attached to the back of the preamplifier via the provided 3 meter interconnect if remote
operation is desired. The remote control receiver box may be placed anywhere within
line of sight of the hand-held remote transmitter. A longer remote receiver cable may be
ordered on a custom basis from the factory for special applications.

Inputs 1-6 are normally used as line level inputs. If the preamplifier is equipped with the
phono option, then the input 1 RCA connectors become phono inputs. The phono inputs
on a phono-equipped Consonance cannot be used as line level inputs without incurring
possible damage to the preamplifier phono circuitry. A ground "thumbscrew" is located
near the input 1 connectors for use as a ground connection for phono operation.
Normally, this ground connection would not be used when the Consonance is used
exclusively as a line level preamplifier.

Balanced Main output signals are always produced by the preamplifier circuitry and are
available regardless of any input signal source chosen. Single ended Main output signals
are available at the NORMAL output connectors. Signals inverted by 180 degrees relative
to the NORMAL signal outputs are available at the INVERT output connectors.

The Consonance Preamplifier can be adjusted to facilitate different input and output
impedances and gain structures. These adjustments are located internally and require
the removal of the top cover. They can be performed easily, provided the instructions
located in this manual under the heading "Impedance Matching" and/or "Adjustable
Gain" are followed precisely. If you are in any doubt as to the proper adjustments to be
made, contact your dealer or the factory for assistance.

Phono/Line Input Impedance Adjustments

The Consonance Preamplifier permits you to optimize the input impedance of all inputs.
This will optimize interconnect performance by minimizing source and load interactions.
Impedance for all inputs can be set internally. Some sources cannot be loaded at the
lowest input impedance option available on this preamplifier (300 ohm). In these cases,
the high input impedance option should be selected (50K).

The Consonance Preamplifier is shipped from the factory at a 50K ohm input impedance
and a 300/600 ohm balanced output impedance. If you are unsure as to what input
impedance settings to use, simply leave the switches in the positions set at the factory.

If you desire to adjust the impedances, the preamplifier’s top cover must be removed.
With a number 2 Phillip’s screwdriver, remove the three flat head screws closest to the
top on each side of the preamplifier. Also, remove the one screw located in the center
back top of the top cover. The top cover can now be lifted directly up from the
preamplifier. While facing the front of the preamplifier, locate a light blue switch housing
nearest the TAPE OUT connectors. This is the Line Input Impedance switch. (Please refer
to the diagram on page 7.) Gently slide each white switch to the desired location as
outlined on page 8. Each switch, when moved to the "ON" position, terminates its
respective input with a 300 ohm input impedance. If no switches are selected "ON", then
each input will be terminated with a 50K ohm input impedance. Any or all inputs can be
adjusted in any impedance option desired.

The Consonance Preamplifier also provides options for setting cartridge loading
impedance when using the phono option. Two options are available: twelve switch­selectable load impedances or plug-in sockets which allow the installation of any fixed
value resistor. The selectable load impedance switches are located adjacent to the phono
module (please refer to the diagram on page 7 of this manual). To adjust, gently slide
each white switch to the desired location for both switch housings as shown in the phono
cartridge loading diagram on page 8.

If a cartridge loading value is required which is not offered by the twelve switches, then
a resistor can be inserted into the appropriate sockets located between the two cartridge
loading switches described above. This option requires that the loading switches be set
in the 47K ohm position (all off). The phono loading socket consists of two parallel rows
of seven sockets each. For best performance, a 1% metal film 0.25w resistor should be
used. The selected resistor would be installed between these two rows of sockets (i.e.
one end of the resistor in one row and the other end of the resistor in the adjacent
socket in the other row). The three end sockets in each row are the active loading
sockets for each channel and are electrically connected and in parallel. The middle
socket in each row is connected directly to ground and is not used. If additional loading
capacitance is needed, then a suitable capacitor can be installed in the same way. With
no capacitor installed, the input capacitance of the Consonance Preamplifier is
approximately 150pf.