JEFF ROWLAND 501 User manual

OWNER’S MANUAL MODEL 501 MONO AMPLIFIER

© Jeff Rowland design gRoup 2007. all Rights ReseRved.
TABLE OF CONTENTS
OWNER’S MANUAL MODEL 501 MONO AMPLIFIER
Introduction 2
Product Features 3
Package Contents 4
Initial Inspection 5
Maintenance & Cleaning 6-7
Protection Systems 7
Installation, Use & Care 8-9
Signal & Power Connections 10-12
Specications 13
Dimensions 14
Optional Adjustments 15

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2
If you have any additional questions
regarding the installation or operation
of the Model 501 Mono Amplifier, please
contact your authorized Jeff Rowland
Design Group dealer or check the Jeff
Rowland Design Group web site at
www.jeffrowland.com.
Enjoy the music!
Jeff Rowland
President,
Jeff Rowland Design Group
to gain the maximum performance and
ease of use for which this amplifier was
designed. Please note that your Model 501
Mono Amplifier serial number begins with
the letters “MD”. This serial number is
located on the rear panel of the chassis.
Please include this number with any corre-
spondence regarding your Model 501
Mono Amplifier. 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.
Welcome to the Jeff Rowland Design
Group “family” and congratulations on your
purchase of what is unquestionably one
of the world’s finest amplifiers. With its
combination of features such as precision
electronic circuitry, exceptional
efficiency,
and accurately machined chassis compo-
nents throughout, your
Model 501 Mono
Amplifier will offer you many years of musi-
cally satisfying enjoyment.
Please 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 operational features will allow you
INTRODUCTION
OWNER’S MANUAL MODEL 501 MONO AMPLIFIER

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3
• XLR input connector for balanced
system congurations. Same gain
and input impedance characteristics
are ensured whether XLR or RCA
adapted inputs are used.
• Transformer coupled input provides
universal compatibility with other
components and eliminates ground
loop noise and EMI.
• High efciency ICEpower® power
conversion technology generates
high output power with very little heat,
promotes long component life and
permits a relatively small physical size.
• Multistage AC line ltering in power
supply reduces AC line noise pollution
throughout amplier signal circuitry.
• CE approved speaker output terminals
require no tools for secure, low resis-
tance connections.
• Fully-balanced topology implemented
in both input and output circuitry.
• Proprietary switch-mode power
supply technology ensures
consistent performance under all
operating and AC line conditions.
• Low power consumption permits
constant power-up operation to
eliminate warm-up time.
• Selectable overall gain of 26 or 32 dB.
• Ultra-low resonance, structurally
rigid chassis, precision-machined
from a solid block of aircraft grade
6061-T6 aluminum.
• Remote ON/OFF input jack allows
amplier standby operation from
a
remote source for inclusion into
home
theater (A/V) systems.
PRODUCT FEATURES
OWNER’S MANUAL MODEL 501 MONO AMPLIFIER

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Ensure that all of the auxiliary components listed below are enclosed within the shipping carton
and accessory box. Refer to the illustrations and verify that the proper components are included.
PACKAGE CONTENTS
OWNER’S MANUAL MODEL 501 MONO AMPLIFIER
OWNER’S MANUALMODEL 501 MONO AMPLIFIER AC POWER CABLE
WARRANTY REGISTRATION
WARRANTY CARD

© Jeff Rowland design gRoup 2007. all Rights ReseRved.
5
Inspect the shipping container for damage. If any portion of 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 notication and inspection within 24 hours of delivery to determine the nature of damages incurred.
Your Model 501 Mono Amplifier 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 amplifier does not operate correctly,
please notify your dealer immediately.
We strongly suggest that you save all of the packing materials. If the amplifier is returned to your
dealer or JRDG, the original packing materials must be used for shipment to avoid possible damage.
Neither JRDG 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 JRDG issue a Return Authorization
(RA) number prior to shipment.
INITIAL INSPECTION
OWNER’S MANUAL MODEL 501 MONO AMPLIFIER

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All JRDG products are designed to provide a lifetime of enjoyment
and listening pleasure. The Model 501 Mono
Amplifier is uniquely
constructed from a solid block of precision-machined aluminum.
It’s 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 amplifier 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.
• Please allow the front panel, which is coated with an automotive-grade polyure-
thane nish, 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 front panel of the unit should never be cleaned with anything other than a very
soft cotton cloth and plain water or ne oil-based furniture polish. Because of the
ne nish of the front panel, use of any other cleaning agent may permanently
scratch the nish.
• The top cover, sides and bottom are protected by a durable black anodized nish
and can be cleaned with a soft cotton cloth (such as an optical lens cleaning cloth
or ne furniture polishing rag) 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.
Maintenance & cleaning
OWNER’S MANUAL MODEL 501 MONO AMPLIFIER

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7
Protection SyStemS
The Model 501 Mono Amplifier is equipped with internal 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
amplifier will not be used for extended periods of time, the 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.
If you have any questions about the care or cleaning of your Model
501 Mono Amplifier, please contact your dealer or the JRDG 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.
NOTE: Cleaner/polish should be applied directly to the cloth and not the chassis.

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InstallatIon, Use & care
OWNER’S MANUAL MODEL 501 MONO AMPLIFIER
Locate the amplifier as close as possible to its final installation point. Allow access to the rear
panel for making connections. Due to it’s design, the Model 501 Mono Amplifier is energy
efficient, eliminating the need for heatsinks or forced-air cooling. As a result, the Model 501
Mono Amplifier can be housed in a cabinet or custom enclosure with no fear of overheating.
The efficient and compact design of the Model 501 allows it to be installed in any number of
music, film and surround sound systems. For connection instructions for use in a typical two-
channel stereo system, please see page 11 of this manual.
The main chassis of the Model 501 is precision-machined out of a solid block of aluminum to
create as rigid an enclosure as possible, impervious to lateral and torsional forces. The amplifier
is particularly non-resonant; however, various damping and resonance control accessories
may be used to yield greater audio performance in some audio systems.
RISK OF ELECTRICAL SHOCK!
WARNING : Do not attempt to access the interior of the MODEL 501 MONO AMPLIFIER by removing the bottom
cover. Doing so will void your warranty and could expose you to dangerous, potentially lethal electrical voltages.

© Jeff Rowland design gRoup 2007. all Rights ReseRved.
9
The JRDG Model 501 Mono
Amplifier has been designed to
operate at the highest level of
efficiency and performance in
any normal operating situation;
however, there are a few impor-
tant use and care principles
that must be kept in mind when
operating the amplifier.
• Do not expose the amplier to
rain, moisture, or excessively
damp conditions.
• Make sure that the voltage on the
backside of the panel matches the
mains voltage in your area.
•
The Model 501 Mono Amplier
must not be modied in any way,
other than according to ofcial
service bulletins from JRDG.
Otherwise, the factory warranty
will be immediately voided.
• Be sure the amplier power switch
is turned off or AC power cable
is removed
before connecting or
disconnecting any loudspeaker or
interconnect cables.
• When operating the Model 501,
a
properly grounded AC receptacle
should be used. A potential shock
hazard may result if the supplied
3-wire, grounded AC cable ground
terminal is defeated or lifted or
the unit is connected to a 2-wire
ungrounded AC outlet.
• The Model 501 is designed to per-
form
optimally with no adjustments
or
maintenance for the lifetime of the
product. Do not attempt to open the
bottom cover of the amplier and
refer all service issues to qualied
personnel. The voltages inside the
Model 501 can be hazardous.
• Because of the energy efciency
of the Model 501, there is no need
to turn the unit off when not in use
except in the event of severe voltage
hazards as mentioned previously.

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The Model 501 Mono Amplifier offers unprecedented compatibility with
associated audio and A/V components. When connecting or discon-
necting speaker or interconnect cables, the amplifier Master AC Power
Switch (5) should be turned OFF.
(1) POWER INDICATOR LED: When the amplifier is connected to
AC mains and the Master AC Power Switch (5) is turned ON, the small
front panel power indicator will illuminate blue. When the Master AC
Power Switch is OFF, the indicator will be off.
(2) BALANCED SIGNAL INPUT: If you are using balanced XLR inter-
connects from your source components, they should be connected to
the balanced input connector. The connector unlocking tab must be
pressed to disconnect the XLR interconnect cable from the amplifier.
NOTE: Pin 2 of the XLR connector is signal positive with respect to speaker output positive.
Also, JRDG recommends balanced cables as the preferred method of interconnection.
XLR to RCA adaptors are available from JRDG if RCA, single-ended interconnects are
used. Amplier gain is not affected by choice of input type.
1
100
4 53
26
Signal & power connectionS
OWNER’S MANUAL MODEL 501 MONO AMPLIFIER

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(3) LOUDSPEAKER OUTPUT: Unscrew the knob that secures the speaker output connector
and pull the securing block out far enough to allow access to the binding posts. Install the
positive (usually red) loudspeaker cable spade terminal to the positive (+) binding post and the
negative spade terminal to the negative (-) binding post. Secure the loudspeaker connections
by tightening the knob securely with your fingers. The Model 501 will only accept spade termi-
nated loudspeaker cables. Banana plugs or bare wire connections can be used but require an
optional clamp available from your JRDG Dealer.
(4) AC INPUT CONNECTOR: 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.
Install the AC Power Cable between the AC input connector and your AC mains outlet.
(5) MASTER AC POWER SWITCH:
This switch controls the operating status of the amplifier.
Pressing the “I” symbol on the switch will turn the amplifier
ON . Pressing the “ O ” symbol on
the switch will turn the amplifier
OFF .
Signal & power connectionS
OWNER’S MANUAL MODEL 501 MONO AMPLIFIER
WARNING: Both positive and negative outputs
are electrically active with respect to chassis
and/or system ground potential. Therefore, this
amplier cannot be used in certain loudspeaker
switching congurations, such as those used in retail
demonstrations. Failure to avoid these precautions
may short the outputs to ground and can result in
damage to the amplier and will void the warranty.
Certain subwoofer speakers which derive signals from
amplier outputs will require additional circuitry to
properly isolate the amplier output. Please contact
JRDG before connecting these types of subwoofers.

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POWER CONDITIONING: AC power conditioners and AC mains power
cables are a common accessory in many high performance audio and
video systems and can be used to improve the quality of reproduction
in certain instances. We have tried to provide the best possible basic
power cord with the Model 501, however many users wish to experiment
with more expensive and esoteric accessories. As we have never found
the perfect or universal power conditioner or cable, it is not possible to
recommend any particular type or brand for use with the Model 501 Mono
Amplifier. Please use your dealer’s help and knowledge as a resource to
select the proper accessories for your individual system needs.
NOTE: Due to the exceptionally low power consumption rating of the Model 501, it is
recommended that the unit not be disconnected from AC mains unless it is to be moved or
reinstalled in another location. It is recommended that the amplier simply be left on when
the unit is not in use.
WARNING: Serious damage to internal circuitry can occur if improperly wired or
unapproved AC power cords are used. Your dealer can be a helpful resource for
selecting the proper accessories for your needs. Also, if the unit is plugged into a voltage
different from the
range listed on the back panel, it will result in serious damage and will
void
the warranty.
(6) 12V REMOTE TRIGGER: A 1/8” (3.5 mm) mini-plug connector
is provided on the rear
panel for remotely switching the amplifier
between Operational and Standby modes. When connected to
another component with the proper circuitry, the amplifier standby
function can be turned ON and OFF remotely in a custom installation,
theater, or automated system setup. (See FIGURE 1)
FIGURE 1: Detail of 12V remote trigger and mini-plug connector
requirements
NOTE: Please be aware that the remote feature simply places the
amplier in standby mode and does not disconnect the unit from
power or AC mains.
NOTE: If a 12V DC switching source is not available, then a short
circuit between the “tip” and “sleeve” of the 1/8” mini-plug connector
will place the amplier into the STANDBY MODE. Removing the
short circuit will return the amplier to the OPERATIONAL MODE.
Constant 3v To 15v DC Signal
(12VDC Typical) (tip)
Ground (sleeve)
Signal & power connectionS
OWNER’S MANUAL MODEL 501 MONO AMPLIFIER

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13
Output Power, Continuous RMS 500 watts @ 8 ohms, 1000 watts @ 4 ohms
Frequency Response 5 Hz – 45 kHz, -3 dB @ 8 ohms
Peak Output Current 40 amps
Dynamic Range 120 dBa
Load Impedance Range 2 ohms – 16 ohms
Input Impedance 40k ohms
THD + Noise, 0.1 watts – 500 watts, 4 ohms < 0.1%, Typically .01% @ 1 kHz
CCIF Intermodulation Distortion, 19/20 kHz < .002%
Damping Factor @ 1 kHz > 1000
Overall Gain (Balanced or Unbalanced) Selectable Internal Jumper, 26 or 32 dB
Common Mode Rejection Ratio > 90 dB, 20 Hz – 20 kHz
Absolute Phase Non-inverting, Pin 2 Positive
Inputs 1 Balanced (XLR)
(Unbalanced operation requires an optional XLR to RCA adapter)
Outputs 1 CE-Approved Speaker Wire Clamp
Power Consumption Idle – 15 watts, Maximum – 1300 watts
Amplifier Weight
17 lbs. / 7.8 kg
Overall Amplifier Dimensions (H) x (W) x (D) 3.3” x 8.4” x 14.6”
85mm x 213mm x 372mm
SPECIFICATIONS
OWNER’S MANUAL MODEL 501 MONO AMPLIFIER

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14.6 in. (372 mm)
3.3 in. (85 mm)
8.4 in. (213 mm)
2.8 in. (72 mm)
DIMENSIONS
OWNER’S MANUAL MODEL 501 MONO AMPLIFIER
13.0 in. (292 mm)

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15
OWNER’S MANUAL MODEL 501 MONO AMPLIFIER
OPTIONAL AdjusTmeNTs
RISK OF ELECTRICAL SHOCK!
WARNING: The instructions in this section are meant for qualied JRDG service
per sonnel only; however, if you as an end user choose to attempt these adjustments
yourself, JRDG cannot be held liable for any damage that may occur to your Model 501
Mono Amplier because of your actions. Further, accessing the interior of your Model
501 by removing the bottom cover can expose you to dangerous, potentially lethal
electrical voltages. Thus, JRDG cannot be held liable for any injury you may sustain
should you undertake any of these adjustments yourself.
ADjUSTING AMPLIFIER OVERALL GAIN
STEP 1:
Unplug the Model 501 Mono Amplifier power cable
from the
wall AC outlet.
STEP 2:
Place the unit upside-down on a soft, clean surface.
Using a #2 Phillips screwdriver,
remove the ten screws that
secure the
bottom cover of the unit.
STEP 3: Locate jumper J103 on the rear panel board of the unit.
Using needle-nose pliers, move the jumper from between pins
2 and 3 to pins 1 and 2. (See FIGURES 1 and 2). Overall amplifier
gain increases to 32 dB.
STEP 4:
Reinstall the bottom cover and replace the ten screws
to secure it to the chassis.
FIGURE 1: Location of Jumper J103 on the inside back
panel of the Model 501
j103
(DEFAULT) 26 dB GAIN
j103
(ALTERNATE) 32 dB GAIN
jUMPERS
FIGURE 2: Close-up of J103
settings for the Model 501
1 2 3
1 2 3

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