JEFF ROWLAND Conductor User manual

© Jeff Rowland Design Group 2019・All Rights Reserved
C O N D U C T O R
PHONO PRE AMPLIFIER

TABLE OF CONTENTS
Note From Jeff Rowland Design Group 3..........................................................
Introduction 4.......................................................................................................
Safety Instructions 8.............................................................................................
Protective Systems 9.............................................................................................
Limited Warranty 10............................................................................................
Owners Manual Use 12........................................................................................
Maintenance and Care 13....................................................................................
Unpacking and Placement 15..............................................................................
Front Panel Operations 17...................................................................................
Rear Panel Connections 19..................................................................................
INVERSE RIAA Network 21..............................................................................
Conductor Cartridge Loading Chart 23............................................................
Conductor High Output Moving Coil Dip Switch Chart 24............................
Specifications 25...................................................................................................
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NOTE FROM JEFF ROWLAND DESIGN GROUP
Welcome to the Jeff Rowland Design Group “family” and congratulations
on your purchase of what is unquestionably one of the world’s finest Phono
pre-amplifiers. With its combination of features such as precision electronic
circuitry, exceptional efficiency, and accurately machined chassis
components throughout, your CONDUCTOR 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 Conductor Phono Pre-
amplifier. A thorough understanding of the operational features will allow
you to gain the maximum performance and ease of use for which this phono
pre-amplifier was designed.
Please note that your CONDUCTOR serial number begins with the letters
“PS”. Please include this number with any correspondence regarding your
Conductor It has been my joy to create an audio component of enduring
value that reflects the highest ideals of musical and artistic expression. It is
my hope that these qualities will enrich your experience and pride of
ownership.
If you have any additional questions regarding the installation or operation
of the CONDUCTOR please contact your authorized Jeff Rowland Design
Group dealer or check the Jeff Rowland Design Group web site at http://
jeffrowlandgroup.com.
Enjoy the music!
Jeff Rowland!
President, Jeff Rowland Design Group
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INTRODUCTION
The Conductor Phono Preamplifier was designed for the discriminating
music listener to provide the highest quality playback of a wide variety of
modern and vintage phonograph records. A versatile feature set permits
the use of this preamplifier in any high quality audio system. A list of
these features with a short technical description is presented below.
1. The CONDUCTOR can be ordered with one to four active
cartridge inputs. Inputs 1,2, and 3 are dedicated for Moving Coil
(MC) cartridges and Input 4 is dedicated only for Moving Magnet
(MM) or High Output Moving Coil (HOMC) cartridge types. For
example, this feature allows the use of phono turntables with
multiple tonearms, each with a particular tonearm/cartridge
combination optimized for a users unique preference or quality.
Since each input preamplifier circuitry is independent from one
another, each input can be optimized with regards to gain, loading
and other parameters which will be explained later in this manual.
Additionally, this feature allows input switching to occur at a
higher “line level signal” instead of switching at the microvolt
signal level of a phono cartridge where signal degradation is more
likely to occur.
In whatever input configuration the CONDUCTOR is ordered,
machined cover plates are installed over the unused inputs for an
uncluttered rear panel look.
2. Both balanced (XLR) and unbalanced (RCA) interconnect options
are provided for all MC inputs and main outputs. Only RCA input
jacks are provided for the MM input option, however all inputs and
outputs are transformer coupled for noise elimination and galvanic
isolation. There is no gain difference between any paired balanced
or unbalanced input or output.
3. The CONDUCTOR incorporates custom made input transformers
for all inputs. These unique transformers, co-developed between
Lundahl and JRDG, are wound with high purity copper wire
sourced from Cardas Audio and specifically designed with a low
turns ratio to ensure minimum copper losses and extremely low
noise in conjunction with the active low noise circuitry directly
following the transformers. A very low turns ratio was chosen to
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ensure the highest signal bandwidth possible, since a higher turns
ration would limit bandwidth. A transformer cartridge interface
prevents the input current of the first stage active circuitry from
flowing through the connected phono cartridge coils, thus
preventing the micro-magnetization of the connected cartridge.
The active circuitry can thus have a defined and constant low
impedance dc Current path, providing stable operating parameters
independent of different connected cartridge types. The
transformer also provides the ideal “coil to coil” balanced, ground
isolated interface between the phono cartridge and active circuitry,
offering an extremely high common mode rejection of common
mode noise present on the unshielded tone-arm and interconnect
wiring. Additional differential-mode noise filtering is also provided
which prevents intermodulation distortion in the first gain stages of
the amplification circuitry due to RF and EMI ingress. The
transformer cartridge interface is provided with both XLR and
RCA input connector types.
4. The CONDUCTOR can be ordered with two different types of
input transformer core materials, standard or high-grade
amorphous type.
5. Phono cartridge loading is performed by individual thin-film
resistors inserted on the input transformer secondary with precision
relays, selected by rear panel mounted toggle switches for easy
switching. This loading resistor position allows maximum
cartridge signal energization of the transformer primary without
electrical energy being consumed by a direct connected load
resistor. Fourteen individual loading values can be selected by
choosing a particular switch combination listed in the Conductor
Cartridge Loading Chart for Moving Coil Cartridges.
6. For each selected input, fully balanced, low noise, high gain, solid-
state circuitry provides the necessary gain and equalization. The
signal is maintained and amplified differentially to preserve a high
common-mode noise rejection and provides excellent immunity
from overload. All signal amplification is provided with a total of
three wide-band, flat gain stages, optimized to maintain all
distortion and noise products less than 100 dB below operating
signal level throughout the full audio bandwidth. Equalization to
conform to the RIAA standard and additional EQ curves are
provided via hand selected capacitors and 0.1 % thin film resistors.
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7. An optional handheld wired remote control box can be plugged
into the rear panel of the CONDUCTOR to provide different
equalization curves for playback of selected vintage recordings.
8. A two-pole (12 dB/octave) maximally flat high-pass filter is
incorporated into the signal path for filtering out undesirable low
frequency turntable rumble signals. An internal switch is provided
to insert an additional filter, which working in conjunction with the
two-pole filter, provides an additional attenuation greater than 40
dB at 10 Hertz, a common tone-arm resonance frequency. The
composite effect of these filters will have a minimal result on the
audio pass-band with less than 3 dB of attenuation at 20 Hertz.
9. Any MC input can be modified for higher gain for use with low
output phono cartridges. An additional 6 dB of gain is available.
The gain increase is accomplished by connecting the input
transformer primary windings in parallel for a higher turns ratio
over standard. This allows extra gain without a significant increase
of overall noise. A soldered jumper provides this change without
compromising signal integrity.
10.Front panel push buttons provide selection of Input, Mute,
Standby, Mono and Left minus Right functions. Functional
definitions of these buttons will be covered in the Operation
section of this manual.
11.The CONDUCTOR can be powered with two different external
power supplies. For users that own the optional JRDG Model PSU
power supply, the CONDUCTOR can be plugged into one of the
unused PSU auxiliary DC outputs. The Model PPS-1 DC Power
Supply can also be used to power the CONDUCTOR via its DC
output connector. Both power supply options provide a fully
regulated, low noise direct current power source for the
CONDUCTOR and are designed to be switched on and off via the
CONDUCTOR front panel Standby push button.
12.All of the active circuitry is elastomerically mounted within a
chassis machined from a solid block of aircraft grade 6061 bar-
stock aluminum, providing resonance control and shielding from
external radio frequency interference. Each input amplifier/
equalizer and output circuits are configured as individual
“modules”, which can be exchanged, updated or modified as
needed. All circuitry is strategically placed for the smallest
possible “loop area”, utilizing precision 0.1% thin-film surface
mount (SMD) componentry on four layer circuit boards for the
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lowest possible noise, distortion and field interaction. Individual
low-noise regulators independently power each input, output and
filter sections, which, together with low noise external power
supplies, eliminate all forms of noise from any source.
13.Both models of external power supplies assure quiet, reliable
operation on all worldwide mains voltages.
14.To assist the break-in of all internal circuitry, an Inverse RIAA
Network board is included with the CONDUCTOR. This device is
installed between any line level output such as a tuner or CD
player and any active input of the CONDUCTOR. The line level
source signal is attenuated and pre-equalized such that it can be
safely used to break-in the CONDUCTOR circuitry in much less
time than simply playing phonograph records.
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SAFETY INSTRUCTIONS
The CONDUCTOR Phono Pre amplifier has been designed to operate at the
highest level of efficiency and performance in any normal operating
situation; however, there are a few important use and care principles that
must be kept in mind when operating the CONDUCTOR:
§Read these instructions.
§Retain these instructions.
§Follow all instructions.
§Do not expose the phono pre amplifier to rain, moisture, or
excessively damp conditions.
§Due to auto-ranging circuitry in both power supply offerings, and
dual-stage voltage regulation in the Conductor Phono pre-amplifier,
the audio performance will not be affected by any voltage fluctuations
within the operating voltage range. The CONDUCTOR can be
operated at any mains voltage over the range of 85 to 265 VAC
without any adjustments necessary.
§The CONDUCTOR must not be modified in any way, other than
according to official service bulletins from JRDG (Jeff Rowland
Design Group). Otherwise, the factory warranty will be immediately
voided.
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PROTECTIVE SYSTEMS
Both CONDUCTOR power supplies, the PSU and PPS-1 DC Power
Supply, are equipped with external fuses for protection against excessive AC
current draw; however, since no protection circuitry or system can
completely protect a product from every electrical hazard, certain
precautions should be observed. In the event of severe voltage hazards such
as lightning or when the pre- amplifier will not be used for extended periods
of time, the pre-amplifier should be unplugged from the AC mains to avoid
potential damage to the internal circuitry. All other audio/video system
components should also be disconnected from AC mains power as hazardous
voltages can easily travel throughout an interconnected system.
The crossed-out wheeled bin is the
European Union symbol for indicating
separate collection for electrical and
electronic equipment. This product contains
electrical and electronic equipment which
should be reused, recycled or recovered and
should not be disposed of with unsorted
regular waste. Please return the unit or
contact the authorized dealer from whom
you purchased this product for more
information.
This product complies with European Low Voltage (2006/95/EC)
and Electromagnetic Compatibility (89/336/EEC) Directives when
used and installed according to this instruction manual. For
continued compliance servicing must be referred to qualified service
personnel.
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LIMITED WARRANTY
Jeff Rowland Design Group, Inc. warrants the materials, workmanship, and
proper functioning of this product for a period of five years from the date of
purchase as long as the product was operated in accordance with its
operating manual, the products was not altered or improperly serviced or
prepared, or if the product failed to function from the beginning. In the event
of such a failure, the product will be repaired or replaced by Jeff Rowland
Design Group, Inc. through one of its dealers. This warranty is extended to
the original purchaser only and is non-transferable to any secondary or other
purchaser.
In order to have this product repaired or replaced, the original purchaser
must first obtain the prior authorization of Jeff Rowland Design Group, Inc.
or one of its dealers. Purchaser must then return the product, PACKAGED
IN ITS ORIGINAL CARTON, FREIGHT PREPAID to: Jeff Rowland
Design Group, Inc., 2911 North Prospect Street, Colorado Springs,
Colorado, 80907, or to one of its dealers.
Jeff Rowland Design Group, Inc. reserves the right to inspect any product
which is subject to any warranty claim prior to repairing or replacing it.
Final determination of warranty coverage lies solely with Jeff Rowland
Design Group, Inc. Said determination shall be made as soon as possible
following receipt of the product. Jeff Rowland Design Group, Inc. may, at its
option, require from the purchaser, valid proof of purchase (dated copy or
photocopy of dealer's original invoice). Out-of-warranty claims will be
billed for labor, materials, return freight, and insurance as required. Any
product for which a warranty claim is accepted will be returned to the
purchaser and costs of shipping and insurance will be factory prepaid within
the boundaries of the USA. Units to be shipped outside of the USA will be
shipped freight collect only. This warranty gives the holder specific legal
rights. The purchaser also has implied warranty rights, and may also have
other rights which may vary from state to state.
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Jeff Rowland Design Group, Inc. strives to manufacture the very finest
possible equipment and therefore reserves the right to make changes in
design and improvements upon its previously manufactured models.
THE ABOVE WARRANTY IS THE SOLE WARRANTY GIVEN BY JEFF
ROWLAND DESIGN GROUP, INC. AND IS IN LIEU OF ALL OTHER
WARRANTIES; ALL IMPLIED WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR
PURPOSE SHALL BE STRICTLY LIMITED IN DURATION TO FIVE
YEARS FROM THE ORIGINAL DATE OF PURCHASE AND UPON
THE EXPIRATION OF THIS FIVE YEAR WARRANTY PERIOD, JEFF
ROWLAND DESIGN GROUP, INC. SHALL HAVE NO FURTHER
OBLIGATION OF ANY KIND WHETHER EXPRESSED OR IMPLIED.
Jeff Rowland Design Group, Inc. does not authorize any third party,
including any dealer or representative, to assume any liabilities on its behalf
or to make any warranties on its behalf unless authorized to do so.
Warranty registration cards must be completed and mailed to Jeff Rowland
Design Group, Inc. within thirty (30) days of the date of purchase. If this
product is used in a commercial or industrial application, then special
warranty exclusions may apply. Contact your dealer or Jeff Rowland Design
Group, Inc. for information regarding our commercial warranty policies.
!11

OWNERS MANUAL USE
This owners manual is designed to make installing and using this product as
easy as possible. Information in this document has been carefully checked
for accuracy at the time of printing; however, Jeff Rowland Design Group,
Inc.'s policy is one of continuous improvement, therefore design and
specifications are subject to change without prior notice. If you notice any
errors please feel free to email us at: [e-mail].
This document contains proprietary information protected by copyright. All
rights are reserved. No part of this manual may be reproduced by any
mechanical, electronic or other means, in any form, without prior written
permission of the manufacturer. All trademarks and registered trademarks
are the property of their respective owners.
© Copyright Jeff Rowland Design Group, Inc 2019
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MAINTENANCE AND CARE
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 the interior of the chassis
and thus should never need interior cleaning during the lifetime of the
product. All internal circuitry is maintenance-free such that no adjustments
of any kind are necessary over the lifetime of the product. If the
CONDUCTOR is ever in need of service, updating, or upgrading, it should
only be returned to an authorized repair facility or technician for servicing.
The front panel of the unit is precision-machined in a unique process that
incorporates a diamond tipped cutting tool. This process was refined over
many years to produce an attractive and unique appearance. 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.
NOTE: PLEASE ALLOW THE FRONT PANEL, WHICH IS COATED
WITH AN AUTOMOTIVE-GRADE POLYURETHANE FINISH, 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.
WARNING: 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-BASED
FURNITURE POLISH. BECAUSE OF THE FINE FINISH OF THE
FRONT PANEL, USE OF ANY OTHER CLEANING AGENT MAY
PERMANENTLY SCRATCH THE FINISH.
The top and bottom cover, sides and bottom are protected by a durable black
anodized finish and can be cleaned with a soft cotton cloth (such as an
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optical lens or microfiber cleaning cloth) dampened with plain water. Water
should be applied directly to the cloth and not the chassis. A very mild
plastic or glass cleaner that does not contain ammonia may also be used. If a
mark has been left on the chassis, do not use any type of abrasive or
chemical cleaner to remove the mark.
If you have any questions about the care or cleaning of your CONDUCTOR,
please contact your dealer 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.
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UNPACKING AND PLACEMENT
INITIAL INSPECTION
Inspect the shipping container for damage. If any portion of the shipping
container, packing material, CONDUCTOR chassis, 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 24 HOURS OF DELIVERY TO DETERMINE
THE NATURE OF DAMAGES INCURRED.
Your CONDUCTOR has undergone extensive performance evaluations,
listening tests, quality control inspections, and a minimum 72-hour burn-in
period prior to shipment and should therefore be in perfect operating
condition upon delivery. If the CONDUCTOR does not operate correctly,
please notify your dealer immediately.
We strongly suggest that you save all of the packing materials. If the
CONDUCTOR is returned to your dealer or Jeff Rowland Design Group, the
original packing materials must be used for shipment to avoid possible
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.
UNPACKING
Carefully unpack CONDUCTOR chassis and power supply (if included)
from the original packing box. Remove all accessory items from the
accessory box. Accessories include:
§Operational Manual
§Warranty Card
§DC cable
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§Power Supply (If ordered)
§Inverse RIAA Network and two pair of RCA-RCA interconnect cables
IMPORTANT: RETAIN ALL PACKING MATERIALS FOR FUTURE
TRANSPORT. SHIPPING PRODUCT IN INADEQUATE PACKING
MATERIALS MAY VIOLATE THE JEFF ROWLAND DESIGN
GROUP MANUFACTURER’S WARRANTY.
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FRONT PANEL OPERATIONS
1. The CONDUCTOR can be equipped with one to four active
inputs. Each input can be selected by depressing the desired
INPUT button. A small green light will illuminate directly
above a selected input whether or not a particular input is
active.
2. When the MUTE button is depressed the output level of the
Conductor will be reduced by approximately 40 dB, providing a
reduced, yet slightly audible signal when a record is being
played. A small red light will illuminate directly about the
MUTE button when the CONDUCTOR outputs are muted.
3. Depressing the STANDBY button will place the
CONDUCTOR in operation mode. A small yellow light will not
be present when the CONDUCTOR is operational. Alternately
depressing the STANDBY button will place the CONDUCTOR
in standby where no operation is possible. The small yellow
light will illuminate when the CONDUCTOR is in standby
mode.
4. The MONO button algebraically sums the right and left
channels for playback of monophonic recordings. A small blue
light will illuminate directly above the MONO button when
monophonic operation is active.
5. The L-R button algebraically subtracts the right channel signal
from the left channel signal, effectively producing a difference
signal to aid in cartridge setup. This difference signal is present
at both CONDUCTOR LINE OUTPUTS when the L-R
function is activated. To use this feature, play a test record in
which a reference tone is present, equally, in both channels.
Depress the L-R button and note that the output level decreases
significantly. The cartridge azimuth is then adjusted for the
minimum signal output, which confirms that the optimum
cartridge azimuth has been achieved, and both right and left
channel output levels are as equal as possible. This feature can
also be used in a similar manner to set an ideal anti-skate
adjustment when playing the inner grooves of a suitable test
record. A small white light will illuminate directly above the L-
R button when this function is active..
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1
INPUT 1
Press this button to select input 1, when
input circuitry is installed
2
INPUT 2
Press this button to select input 2, when
input circuitry is installed
3
INPUT 3
Press this button to select input 3, when
input circuitry is installed
4
INPUT 4
Press this button to select input 4, when
input circuitry is installed
5
MUTE
P r e s s t h i s b u t t o n t o m u t e t h e
CONDUCTOR outputs
6
STANDBY
P r e s s t h i s b u t t o n t o p l a c e t h e
CONDUCTOR in or out of STANDBY
mode
7
MONO
Press this button for playback of
monophonic recordings
8
L-R
Press this button to enable cartridge
azimuth adjustments
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REAR PANEL CONNECTIONS
As shown in the diagram, both XLR balanced and RCA
unbalanced input connectors are provided on Inputs 1, 2, and 3
for connecting to your phono turntable with a moving coil type
cartridge. Even though RCA connectors are provided for each
input, the signal from the turntable is still amplified as a
balanced signal and not referenced to an earth ground, even
when connecting to Input 4, for MM and High Output MC
cartridges. For best results, use balanced interconnect cables for
maximum rejection of all types of electromagnetic noise.
Grounding thumbscrews have been provided on each input to
provide earth grounding of a connected phono turntable. Due
to the Conductor’s ability to reject hum fields from any source,
these grounding connections may not be needed in a particular
system.
Four cartridge loading switches are provided for each Input 1, 2
and 3. See the Conductor Cartridge Loading Chart in this
manual for choosing a value approximate to the loading
resistance recommended by the phono cartridge manufacturer.
You may wish to experiment with values other than those
specified. These switches can be switched on and off while
music is being played with no clicks or pops in the signal.
Input 4 is provided with three switches for adjusting loading
capacitance for Moving Magnet cartridges. The capacitance
value assigned to each switch will algebraically add if two or
three switches are switched on at the same time but it is
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unlikely that most MM cartridges would benefit from more than
300 picofarads (PF) of loading capacitance.
(Note that the combined capacitance of the tonearm and
interconnect wiring must be added to the selected capacitance
value of the Conductor.)
The switch above the capacitance values increases the gain of
Input 4 to accommodate High Output Moving Coil Cartridges.
The default input impedance for HOMC cartridges is typically
recommended to be 47k ohms. However, the loading input
resistance can be adjusted internally for values lower than 47k
ohms for potential cartridge performance increases. Values other
than 47 k ohms is only available when the Conductor switch is
set to HOMC. Refer to the Loading Chart for High Output
Moving Coil Cartridges in this manual.)
Both RCA and XLR output connectors are provided for the
Conductor Line Outputs. Due to a transformer output
configuration, both output connectors provide a ground
isolated, balanced signal for the lowest possible output noise
and elimination of system ground loops. The signal level is
equal between the XLR and RCA outputs.
A DC Power Input connector allows the use of an external
power source for eliminating signal contamination from stray
magnetic fields present in most power supplies. Connect the
supplied DC power cable between the external power supply
PSU or PPS-1 DC Power Supply and this connector. Note that
this cable is supplied with both male and female type
connectors for correct installation. To remove this cable, simply
pull on the outer sleeve in the direction to be removed. The
external power source will only be powered on and off when
the STANDBY button on the Conductor front panel is
depressed.
A 5 pin DIN type connector is provided for connecting an
optional cable and EQ switching unit for switching different
equalization curves for playing vintage records.
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