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JEFF ROWLAND
JEFF ROWLAND
D
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G
R
O
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P Model 9T/ Ti
Mono Power Amplifier
Owners Manual Introduction
W
elcome to the Jeff Rowland Design Group family and congratulations on your purchase of what is unquestionably
one of the worlds finest audio power amplifiers.

With its combination of features such as numerous function control
and interconnection possibilities, precision electronic circuitry and accurately machined chassis components throughout,
your Model 9T/Ti Amplifiers will offer you many years of musically satisfying enjoyment.

Please take a few moments to
read the remainder of this Owners Manual. A thorough understanding of the operational features will allow you to gain
the maximum performance and ease of use for which this Amplifier was designed.

Please note that your Model 9T/Ti
Monaural Amplifiers have different serial numbers on all chassis. The Amplifier serial numbers begin with the letter A; the
Power Supply serial numbers begin with the letter P. These numbers are recorded below and are also located on the rear
panel of each chassis. Please include these numbers with any correspondence regarding your Model 9T/Ti Amplifiers.

It
has been my joy to create an audio component of enduring value which will reflect a higher ideal of musical and artistic
expression. It is my hope that these qualities will enrich your experience of ownership.
Enjoy the music!
Jeff Rowland
President
Jeff Rowland Design Group, Inc.
2911 North Prospect Street
Colorado Springs, CO 80907
Phone: 719/473-1181
Fax: 719/633-4158 Product Features
Two parallel connected XLR Balanced Input jacks for balanced
(Differential Mode) system configurations
Two parallel connected RCA Input jacks for unbalanced (single-ended)
system configurations
Two parallel connected speaker output connectors
User-selectable overall gain of 26 or 32 dB
User-selectable input impedance of 36k or 600 ohms for both balanced
and unbalanced inputs.
User-selectable absolute phase on balanced input
User-selectable input muting
User-selectable switching between balanced and unbalanced inputs
Front panel standby/power button illumination can be turned off
during listening
Optional remote (wired or wireless) power ON/OFF switching
Automatic temperature stabilizing circuitry maintains constant
operating temperature
Standby power condition reduces warm-up time
Fail-safe operation provided by user-resetable AC and DC magnetic
circuit breakers located on rear panel
Quiet, transient-free operation during power and function
mode switching
Automatic input muting under anomalous input or output operating
conditions
Balanced Differential Mode circuit topology implemented from input
to output
Plug-in modules, containing critical electronic circuitry, enhance
thermal stability, mechanical integrity and serviceability
Low-resonance, structurally integrated chassis of precision machined
aluminum alloy components
Introduction / Product Features 1
2
3
5
6
Contents
4 Initial Inspection
I
nspect 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 Model 9T/Ti Amplifier 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 Amplifier does not operate
correctly, please notify your dealer immediately.
We strongly suggest that you save all packing materials. If the Amplifier 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
E
nsure that all of the auxiliary components listed below are enclosed
within the four accessory boxes. Please note that an accessory box has been
provided for each Amplifier chassis and companion Power Supply chassis
for a total of four accessory boxes. Refer to the diagrams illustrated above
and verify the components included.
1
Sixteen (16) compliant isolation interface supports
2
Two (2) AC power cables
3
One (1) speaker terminal hand wrench (7/16 inch)
4
Two (2) DC power cables
5
Sixteen (16) spiked coupling interface supports
6
One (1) warranty card (in some countries warranties are provided
by the respective importer)
Initial Inspection / Contents 1
6
4
5
2
3
A
Front & Rear Panel Function Controls Front & Rear Panel Function Controls
Before attempting any system interconnection, please familiarize yourself
with the front and rear panel controls of the Model 9T/Ti Amplifier. The
descriptions below refer to the numbers and letters associated with the
features in the diagram above.
Front Panel
A
FRONT PANEL STANDBY/POWER button: Press to operate
Amplifier. Press again to place Amplifier in standby mode. This button
will illuminate when the Amplifier is operational. When the button is
not illuminated, all Amplifier inputs are muted and internal circuitry is
reverted to power-saving (standby) mode. Note: All ON/OFF power
switching should be initiated ONLY with this button. Anomalous
operating conditions will automatically switch the Amplifier off (no
illumination) and will prevent the Amplifier from being switched back
on again until such a condition is eliminated.
Rear Panel
(Note: All of the switches described below can be switched, if desired, while
the Amplifier is operational and playing music.)
1
INPUT SELECT switch: This switch selects either the RCA single-ended
inputs or the XLR balanced inputs. Note: When the RCA position is
selected, pin 2 of the XLR input is shorted to pin 1.
2
XLR INPUT PHASE switch: This switch selects between two XLR
connector standards in use worldwide. The XLR standard of associated
equipment should be noted and matched with the Model 9T/Ti to
achieve correct absolute phase. The Amplifier is non-inverting with
respect to XLR Pin 3 when the switch is in the upper position.
Furthermore, the Amplifier is non-inverting with respect to XLR Pin 2
when the switch is in the lower position. Regardless of the standard
selected, this switch can be used to conveniently reverse the absolute
phase of the entire audio system when XLR balanced inputs are used.
Note: The XLR standard used worldwide assigns Pin 1 to ground or input
interconnect shield potential.
3
OVERALL GAIN switch: This switch selects between a high (32 dB) or
normal (26 dB) overall gain structure of the Amplifier.
4
INPUT IMPEDANCE switch: This switch selects between a high
(36k) or low (600 ohms) input impedance when using either the XLR or
unbalanced RCA input jacks.
5
INPUT MUTE switch: This switch removes the internal input signal
connection from the Amplifier input circuitry thus permitting input
interconnect cables to be removed or inserted safely without switching
the Amplifier off.
6
FRONT PANEL LAMP switch: When placed in the OFF position, this
switch will cease front panel illumination during listening. Front panel
indication of operational status is restored when the switch is returned
to the ON position.
Front & Rear Panel Function Controls 7
2
1
5
6
1
4
Rear Panel Power Connections Installation
L
ocate the Amplifier as close as possible to its final installation point. Allow
access to the rear panel for making connections.
The Model 9T/Ti Amplifiers and power supplies are convection cooled,
eliminating the need for fan or forced air cooling. When operating, all chassis
should have at least two (2) inches of air space around the heatsink areas.
The chassis can be stacked vertically thus facilitating an upward flow of
warm air currents throughout the vertical heatsink fin areas. This upward
flow must not be impeded or recirculated around the chassis if proper
cooling is to be maintained.
Supplied with your Model 9T/Ti Amplifiers are two different support systems.
An assessment of the supporting structure should be made to determine the
proper system for the Amplifiers. Both spiked and compliant interface
supports can be easily installed within the indentations on each of the four
chassis pods located underneath the corners of each Amplifier and Power
Supply chassis. These system options permit the coupling or decoupling of
the Amplifier and Power Supply chassis to the supporting structure.
As a general rule, most installations allow the Amplifier chassis to be rigidly
coupled to the supporting structure via the spiked coupling interface
supports. In carpeted installations, these supports provide excellent coupling
from the Amplifier chassis to the rigid supporting structure below. In