Audio research LP1 User Manual

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Owner’s Manual

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Model

LP1

Phono Preamplifier

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Contents

Model LP1 Phono Preamplifier

Illustrations 3

Preface 4

Warnings 4

Packaging 4

Front Panel Controls 4

Connections 5

Installation Instructions 5

Operating/ Start-up Procedure 5

Servicing 6

Cleaning 6

Disposal and Recycling Guidelines 6

Warranty Terms and Conditions 7

Specifications 7

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Preface

Please take the time to carefully read
this instruction manual prior to installation
or use of your LP1 phono preamplifier.
Because it is a highly advanced
electronic instrument, there are several
facts and procedures you should know
before you place it in operation.
Just as you would not purchase and
attempt to operate an expensive
camera, computer system or high­performance automobile without first
learning something about performance
parameters and correct operating
procedures, so too your phono
preamplifier requires some familiarization
before you make it part of your music
reproduction system. Your reward, in
terms of maximum performance and a
long service life, will be well worth the
effort.

Warnings

1.To prevent fire, or shock hazard, do not

expose your LP1 to rain or moisture.

2.This unit contains voltages which can

cause serious injury or death. Do not
operate with cover removed. Refer
servicing to your authorized Audio
Research dealer or other qualified
personnel.

3.The power cord on your LP1 is

equipped with a standard three-prong
grounding plug. For absolute
protection, do not defeat the ground
power plug. This provides power line
grounding of the PH8 chassis to
provide absolute protection from
electrical shock.

4.For continued protection against fire

hazard, replace the fuse only with the
same type and rating as specified at
the fuse holder.

DO NOT ATTEMPT TO
OPERATE THIS
EQUIPMENT BEFORE
INSTALLING THE VACUUM
TUBE IN ITS PROPER SOCKET.

Packaging

Save all packaging in a dry place away
from fire hazard. Your LP1 phono
preamplifier 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 LP1
from unnecessary damage or delay.
Note that your LP1 has been shipped
with the vacuum tubes installed in a
protective foam block under the top
cover. With the LP1 unplugged, use a
phillips-head screwdriver to loosen the
fastening screws, remove the top cover
and set aside. Install the numbered
tubes in their respective sockets, refasten
the top cover and store the foam block
with your carton.

Front Panel Controls

POWER ON/OFF: The unit is off when the

front panel LED is not lit; to power on the
LP1, press the Power switch to the
upward position.
MUTE: After unit is on and goes through a
30 second auto-mute warm up cycle,
the LP1 may be unmuted by pressing the
Mute switch to the upward position. The
dimly lit Mute LED inidicates the LP1 is
muted; when brightly lit, the LP1 is
unmuted.

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Connections

INPUT CONNECTORS: There is one set of

RCA input connectors, which should be
connected to your turntable/tonearm
cable.
OUTPUT CONNECTORS: There is one set of
RCA output connectors which should be
connected to line inputs (Direct, Aux,
Spare, Tuner, etc.) of your line
stage/preamplifier. Single ended RCA-to
balanced adapters are available from
Audio Research allowing the LP1 to be
connected directly to a balanced input
preamplifier using single ended RCA
interconnects.
All input/output connectors are gold
plated and connect ‘ground’ before
‘hot’. On disconnect, ‘hot’ is
disconnected first.

Note: A ‘passive’ line stage is not
recommended for use with the LP1 as it
will not provide the gain necessary to
amplify the output of the LP1 to
adequate levels to the power amplifier.

Installation Instructions

While the LP1 does not dissipate an
unusual amount of heat, it is important
that it have a reasonable airflow to
assure long, trouble-free operation.
In addition, the following installation
guidelines will help insure maximum
sonic performance as well as reliable
service.

1.Upright and horizontal mounting is

required if extended operation (longer
than one hour) is contemplated.

2.Do not ‘stack’ the LP1 on top of other

equipment: not only could this cause
overheating, but ‘hum’ may be
introduced into the phono circuits
from the proximity of the power
transformer of the other equipment.

3.Do not operate unit without the top

and bottom covers installed. These are
required both for safety as well as
shielding from interference (except in
service operations).

4.If side-by-side mounting with other

equipment is employed, place the LP1
to the left of the other chassis, so as to
provide maximum spacing between

the transformer of the LP1 and the
other component.

5.In a cabinet which has an enclosed
back, an exhaust fan is desirable so as
not to operate the LP1 in overheated
ambient air. Operation of vacuum tube
equipment for long periods of time in hot
ambient air will shorten tube life and
increase chance of failure of other
component parts.

Operating/Start-up
Procedure

1.Secure connections between

turntable, LP1, and line stage
preamplifier. Note: Given the
advanced performance capabilities
of the LP1, it is extremely important
that high-quality interconnects be
used for connection to ancillary
electronics.

2.Plug 3-prong power cord into a
grounded AC wall receptacle.

3.Turn Power switch ‘on’. The green
Power LED will light and the Mute LED
will remain dim for approximately 30
seconds while the power supply
stabilizes, indicating the operation of
the automatic muting circuit.

4. After 30 seconds the Mute switch may
be pressed into the upward position,
and the LED will go from bright to dim,
indicating the LP1 is ready for
operation.

Note: For superior sonic performance, a
warm-up period of at least one hour is
recommended.

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Servicing

Because of its careful design and
exacting standards of manufacture,
your LP1 should normally require only
minimal routine service to maintain its
high level of performance.

CAUTION: Your LP1 contains
sufficient levels of voltage
and current to be lethal.

Do not tamper with a
component or part inside the unit. Refer
any needed service to your authorized
Audio Research dealer or other qualified
technician.
The vacuum tube inside your LP1 is a
6H30 dual triode. With normal use it
should last approximately 2,000 to 4,000
hours.

Cleaning

To maintain the visual appearance of
your LP1 phono preamplifier,
occasionally wipe the front panel and
top cover surfaces with a soft, damp
(not wet) cloth to remove dust. A mild,
non-alkaline soap solution may be used
to remove fingerprints or similar
smudges. Cleaners containing abrasives
should not be used as they will damage
the ‘brushed’ grain of the front panel
finish. A dry 2-inch pure bristle paintbrush
works well to remove dust from bevels,
reliefs and switches.

Disposal and Recycling
Guidelines

To dispose of this electronic product, do
not place in landfill. In accordance with
the European Union Waste Electrical
and Electronic Equipment (WEEE)
directive effective August 2005, this
product may contain regulated
materials which upon disposal require
special reuse and recycling processing.
Please contact your dealer or importing
distributor for instructions on proper
disposal of this product in your country.
Or, contact Audio Research Corporation
(763.577.9700) for the name of your
importing distributor and how to contact
them. Packing and shipping materials
may be disposed of in a normal manner.

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Limited Warranty

Audio Research Corporation products
are covered by a 3-Year Limited
Warranty, or a 90-Day Limited Warranty
(vacuum tubes). This Limited Warranty
initiates from the date of purchase, and
is limited to the original purchaser, or in
the case of demonstration equipment,
limited to the balance of warranty
remaining after original shipment to the
retailer or importer. In the United States,
the specific terms, conditions and
remedies for fulfillment of this Limited
Warranty are listed on the warranty card
accompanying the product in its
shipping carton, or may be obtained
from the authorized retailer or from the
Audio Research Customer Service
Department. Outside the United States,
the authorized importing retailer or
distributor has accepted the
responsibility for warranty of Audio
Research products sold by them. The
specific terms and remedies for
fulfillment of the Limited Warranty may
vary from country to country. Warranty
service should normally be obtained
from the importing retailer or distributor
from whom the product was purchased.
In the unlikely event that technical
service beyond the ability of the
importer is required, Audio Research will
fulfill the terms and conditions of the
Limited Warranty. Such product must be
returned at the purchaser's expense to
the Audio Research factory, along with
a photocopy of the dated purchase
receipt for the product, a written
description of the problem(s)
encountered, and any information
necessary for return shipment. The cost
of return shipment is the responsibility of
the purchaser.

Specifications

FREQUENCY RESPONSE: ± 0.3dB of RIAA, 10Hz

to 20kHz.

DISTORTION: Less than .019% at .5V RMS SE

output.

GAIN: 47dB at 1kHz.
SWITCHES: Power, Mute.
INPUT IMPEDANCE: 47k ohms (0.7 to 7mV high

output cartridge recommended).

OUTPUT IMPEDANCE: 5.5k ohms Single Ended

(Single Ended RCA connectors). 60k ohms
minimum load and 100pf maximum
capacitance.

OUTPUT POLARITY: Non-Inverting.
MAXIMUM INPUTS: 40mV RMS 1kHz, 100mV

RMS 10kHz.

RATED OUTPUTS: .0.5V RMS Single ended into

100k load (maximum output 15V RMS at 1%
THD at 1kHz).

POWER SUPPLIES: Electronically-regulated low

and high voltage supplies. Automatic 40
sec. warm-up/brown-out mute. Line
regulation better than .01%.

NOISE: 0.4µV RMS IHF weighted equivalent

input noise, shorted input 74dB velow 2mV
RMS 1kHz input).

TUBE COMPLEMENT: (1) 6H30 dual triode.
POWER REQUIREMENTS: 100-135 VAC 60Hz

(200 - 270VAC 50/60Hz) 35 watts maximum.

DIMENSIONS: 11.3" (33 cm) W x 4.5" (11.4 cm)

H x 8.6" (21.8 cm) D. Rear chassis fittings
extend 0.6" (1.5 cm).

WEIGHT: 9 lbs

Specifications subject to change without notice.
©2012 Audio Research Corporation.

3900 Annapolis Lane North

Plymouth, MN 55447

763.577.9700

www.audioresearch.com