Audio Research GSPre User manual
H I G H D E F I N I T I O N ®
GSPre
Stereo Preamplier
User Guide
Thank You.
Thank you for choosing the GSPre to be a part
of your high performance music listening
system. Since 1970, Audio Research has
been creating some of the world’s nest
audio equipment. Each piece is handcrafted
in Minnesota, and has been designed to
provide many years of listening enjoyment.
We understand you are eager to begin
listening; however, please take a few
minutes to read through this guide for
useful information concerning the operation
of your new preamplier. Once installed,
please allow an appropriate break-in
period to fully appreciate the benets this
preamplier will provide to your system.
After reading the user guide, if you have any
further questions regarding your preamplier,
contact your dealer or Audio Research
customer service - they will be happy to help
you make the most of your new component.
Happy Listening!
4
Contents
Operation
Front Panel Controls and Displays
Start-Up
Shut-Down
Break-in
Front Panel Controls
Remote Only Functions
Settings Menu
Auto Shutdown
Processor On/O
Tube Hours
10
11
11
11
12
13
15
16
16
17
Maintenance
Servicing
Cleaning
Disposal and Recycling
Guidelines
Warranty
Specications
18
18
18
19
20
5
6
7
8
9
9
9
9
9
9
Warnings
Installation
Before Operating the GSPre
In Your System
Connections
Back Panel Connections
Input Connectors
Output Connectors
A.C. Power Connection
RS-232 Control
IR Input
12V Trigger Jack
5
Warnings
To prevent re, or shock hazard, do not
expose your GSPre to rain or moisture.
Do not place objects containing water on top of this unit.
This unit contains voltages which can cause serious
injury or death. Do not operate with covers
removed. Refer servicing to your authorized Audio
Research dealer or other qualied personnel.
The detachable power cord on your GSPre is equipped
with a heavy gauge, 3-conductor cable and a standard
three-prong grounding plug. For absolute protection,
do not defeat the ground power plug. This provides
power line grounding of the GSPre chassis to provide
absolute protection from electrical shock.
The appliance coupler (a.c. power connector)
at the rear of this unit must be accessible
for emergency power disconnect.
For continued protection against re hazard,
replace the fuse only with the same type and
rating as specied at the fuse holder.
The power button on the front of this unit, when
o, does not disconnect all power from this
unit. This unit is in sleep mode when not on.
This unit is RoHS compliant.
The GSPre also has automatic muting to help protect
system components in the event of low line voltage.
When sensing low line voltage, the preamp displays ‘Low
Line’ and automatically goes into ‘Mute’. This condition
will persist until the line voltage returns to a safe
operating level; please note the unit will remain in ‘Mute’
even after ‘Low Line’ no longer appears.
Note that automatic muting is only designed to
protect against power line interruptions or severe
voltage drop. It will not mute in the event of
subsonic transmissions from a faulty input source,
amplier failure or speaker malfunction.
A note about packaging...
Save all packaging in a dry place away from re hazard.
Your GSPre preamplier is a precision electronic
instrument and should be properly cartoned any time
shipment is made. You may not have occasion to
return your unit to the factory for service, but if that
should prove necessary, or other occasion requiring
shipment occurs, the original packaging will protect
your GSPre from unnecessary damage or delay.
6
Before operating the GSPre
This unit has been shipped with the vacuum tubes
installed in protective foam in separate boxes packed
inside the shipping carton. Included are two matched
pairs of 6H30 tubes for the line stage, and one matched
pair of 6H30 tubes for the phono preamplier. Remove
the tubes carefully from the protective foam. Using
a phillips-head screwdriver to loosen the fastening
screws, remove the top cover and set aside.
After removing the top cover and the vacuum tubes
packed in protective foam, see the accompanying
illustration for instructions on installing the tubes for
your GSPre in their proper locations in the chassis. Note
that the numbers written on each tube correspond
to a ‘V’ number etched on the chassis next to each
tube socket. Insert each tube rmly, carefully aligning
the tube pins with the corresponding socket holes.
Installation
left channel right channel
phono stage
7
Installation
In your system
To insure normal component life and safe operation
this unit must be operated only in an upright
position. Adequate airow and proper cooling
can occur only if there is no restriction above
and behind the unit and on either side.
The special non-marring elastomer feet provide
adequate spacing and stability only on a smooth,
hard surface, and also assist to isolate the amplier
from spurious vibrations. For upright stability and
best performance, never operate the unit while it is
sitting on a soft surface such as a thick rug or carpet.
Due to its weight, this preamplier must be supported
on a surface specically rated for such a load. Check
with the manufacturer of your support system
to be sure it is rated to handle this weight.
If the unit is to be operated in an enclosure such as an
equipment rack, make certain that adequate airow
above and to each side of the unit is provided.
The ‘ambient’ operating temperature should never
exceed 120 F or 49 C. Improper installation will
cause premature tube failure and will aect your
warranty, as well as the service life of the unit.
It is normal for a vacuum tube preamplier to run
quite warm, and if used for prolonged periods, hot
to the touch. All components within are, however,
operated at safe, conservative levels and will not
be improperly aected thereby, providing the
requirements outlined above are adhered to.
Do not stack the preamplier on top of a power amplier:
not only could this cause overheating, but hum may be
introduced into the preamp from the proximity of the
amplier’s power transformer.
Do not stack components or other objects directly on top
of the GSPre.
8
Connections
Back Panel Connections
A.C. Power
Connector
IR Input
12V
Trigger
RS-232
Connector
Fuse
Holder
Inputs Main
Outputs
9
Connections
Input Connectors
The GSPre provides four pairs of single-ended input
connectors: SE1 - 3, and PHONO. Please note that
input SE3 can be selected as a unity gain ‘processor’
input; in this case, SE3 should only be connected to
a component with a volume control (such as a home
theater processor). For further information about the
SE3 processor mode, see the section ‘Processor’ on page
16. In addition, there are two pairs of balanced input
connectors: BAL1 and BAL2.
Note
The phono stage of the GSPre has a gain of 58 dB; please
keep this in mind when selecting a phono cartridge to pair
with your preamplier. Audio Research recommends a
phono cartridge within an output voltage range of 0.5 mV
to 2.5 mV.
Output Connectors
One pair of balanced and one pair of single-ended main
output connectors are provided.
A.C. Power Connection
It is important that the GSPre be connected via its
supplied 15 amp IEC 14-gauge power cord to a
secure, dedicated A.C. power receptacle. Never
connect to convenience power receptacles on other
equipment. Only use the power switch on the front
of the GSPre for On/O control of the preamplier,
or the IR input, RS232 or remote control.
RS-232 Connection
The RS-232 connection allows for remote control via
systems such as Creston or other automation systems.
IR Input
The IR input can be used to link the GSPre to an IR repeater
system with a standard mono 1/8” connector.
12V Trigger Jack
The +12V DC output connector provides the ability to
remotely turn on and o other linked components such
as power ampliers having similar capabilities.
10
Operation
Input
Select
Volume
Control
Cartridge
Impedance
Front Panel Controls and Displays
Menu Button
Power
On/O
Function
Indicators
Function
Buttons
side panel
Headphone
Output
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