Plinius KORU User manual
The heart of music
www.pliniusaudio.com
KORU
Phono Preamplifier
Instruction Manual
Contents
Introduction ...............................................................................................................2
Design Philosophy ...............................................................................................3
Unpacking ....................................................................................................................4
Placement & Ventilation ....................................................................................4
Care & Maintenance............................................................................................5
Precautions ................................................................................................................6
Front Panel Functions ........................................................................................7
Rear Panel Functions .........................................................................................7
Installation & Operation ....................................................................................9
Product Features ..................................................................................................11
Troubleshooting .......................................................................................................13
Specifications ..........................................................................................................14
Index ................................................................................................................................15
All operational, technical and descriptive material in this publication
is subject to change at any time without notice. For further product
information or queries, please contact your Plinius dealer.
Plinius products are designed and manufactured by
Plinius Audio Limited, New Zealand.
2 PLINIUS KORU
Introduction
Congratulations on your decision to become the proud owner of this
Plinius Koru Phono Preamplifier.
This manual has been prepared to help you understand the operation of your amplifier,
and to provide information about its design and the variety of ways it may be used.
We have designed and manufactured this amplifier to reproduce your favourite music
faithfully and accurately. With a little care and a full understanding of the operating
recommendations in this manual, your Plinius Koru Phono Preamplifier will provide
years of high-quality, trouble-free performance.
Please take the time to read this manual thoroughly before using your phono preamplifier.
SERIAL NUMBER
FINAL TEST CERTIFIED BY
3PHONO PREAMPLIFIER
Design Philosophy
From a distance you can see that the design of the Plinius products is more than
an applied styling exercise to the front panel. We have started from the ground up
to produce a casing for our electronics that is unrivalled in its physical strength and
visual simplicity.
Wherever possible we have reduced the number of parts needed and then invested
massively in refining and producing the remaining parts to the highest quality
achievable with state of the art computer controlled machines allied with expert
craftsman. Examples of this approach include the hydraulically formed corners on
the amplifiers giving much greater strength and the one piece housing for the remote
control that looks, feels and genuinely is robust.
As with music that you are not familiar with, truly innovative new designs can take time
to understand and enjoy. How often have you heard music that you were first unsure
of, that over repeated listening, has become a firm favourite?
Our designs are fundamentally different to many other companies, and we hope that
you will take the time to explore their unique character and qualities because we have
not made them different simply to be different. We genuinely believe that their visual
and tactile qualities do improve the experience of listening to music and that is our
design goal!
Ross Stevens
DESIGN DIRECTOR
4 PLINIUS KORU
Unpacking
Open the box from the top and remove the accessories from the foam end caps.
You may now proceed to lift the unit from the box, Once the unit is removed you can
proceed with the removal of the foam end caps. These caps are designed to fit on
the front and back of the unit for maximum protection. Retain the packaging for future
transportation of this unit.
Placement & Ventilation
This Plinius product may operate at a moderately high temperature, especially
during extended listening sessions. With this in mind, we recommend the following
guidelines for placement and ventilation:
• The ideal location is upon a rigid stand, away from direct contact with any
temperature sensitive materials, furniture or deep pile carpets.
• Ventilation through and around the amplifier should be kept unimpeded.
• Ensure heat vents (slots in the lid) are not covered or restricted in any way.
• Equipment racks should be of an open type with no closed side panels and no
closed front or rear panels. Ensure a minimum of 100mm clearance on all sides of
your Plinius unit to other equipment and the shelf above.
• If the unit is in an enclosed cabinet, the clearance should be greater than 200mm
on all sides. Ensure the space between the chassis and shelf below the unit is
unobstructed at all times.
• When stacking separate audio components, apply the minimum clearances above,
as well as a minimum of 400mm clearance above the top unit for suitable airflow.
• NOTE: This unit has been designed for use in moderate climates only, not for tropical
conditions.
The design of this Plinius product incorporates a very high level of mechanical
decoupling of the input and output. It can however still be influenced by acoustical
feedback in the operating environment. The use of acoustic cones or a suitably
spiked amplifier stand or table may further enhance the performance of this amplifier.
Consult your Plinius dealer for further advice if required.
5PHONO PREAMPLIFIER
Care & Maintenance
With simple care and maintenance your Plinius product can be kept looking and
operating like new for many years to come.
MAINTAINING THE CONNECTORS
Exposed connectors such as the RCA connectors will be subject to environmental
factors, and over time the surface may degrade. This can be greatly reduced by fitting
readily available ‘RCA caps’ to reduce the effects of environmental elements on the RCA
connectors. These RCA caps or RCA shorting caps can also provide sonic benefits.
Connector cleaning products are also available to clean the RCA and cable connectors
and frequent checks and cleaning will help maintain a good signal connection.
NOTE: DO NOT use RCA shorting caps on output connectors or power amplifier input
connectors. Use RCA shorting caps on unused preamplifier stage input connectors only.
Standard RCA shielding caps can be used on any unused input or output connectors.
MAINTAINING THE SWITCHES
Switches should be maintained by using each various switch setting periodically.
Even if a switch or a switch setting is not used, it is a good idea to toggle small
switches and turn rotary switches though the full range of the switch several times in
succession to keep the contacts active. Performing this simple action will promote
longevity of the switch contacts.
SURFACE CLEANING
From time to time you may wish to clean the surface of your Plinius equipment to
remove dust, or any material build up from the atmosphere or on commonly used
controls. Your Plinius product is made up of parts that have a hard anodised or a
powder coat finish and will clean easily without being damaged.
Cleaning should be carried out using a soft cleaning cloth, dry or with either a small
amount of water or a very mild surface cleaner, while observing the following guidelines:
• As a safety precaution, always switch the equipment off prior to cleaning
• Always use a cloth that is soft and clean
• Never use abrasives or polishing compounds anywhere on the unit
• Never apply liquid directly to the surface of the unit
• Use the cloth dry or with mild surface cleaners of either liquid or foaming type
• Apply only small amounts of cleaner to the cloth
• DO NOT rub the surface but wipe clean only. Excessive rubbing may dull powder
coat or wear the screen printed text.
6 PLINIUS KORU
Precautions
PLEASE TAKE SPECIAL NOTE OF THE FOLLOWING PRECAUTIONS
BEFORE OPERATING YOUR NEW PHONO PREAMPLIFIER.
• DO NOT leave flammable material on the phono preamplifier whilst running, as
this could pose a serious fire risk.
• This phono preamplifier operates at hazardous voltage levels. There are some
alterations that may be made by you, the owner. However, we recommend
that any work requiring removal of the lid be referred to a suitably qualified and
experienced service technician.
• DO NOT attempt to connect any input of this preamplifier to its own outputs.
• DO NOT earth any output terminal or connect any of these terminals together
without following the instructions in this manual or seeking qualified assistance.
• DO NOT place this phono preamplifier in any position where liquids, or any foreign
material may accidentally enter it.
• DO NOT connect any voltage source, short circuit, earth/ground or appliance (other
than suitable audio preamplifiers) to the phono preamplifier output terminals.
• DO NOT connect any voltage source, short circuit, earth/ground or appliance
(other than suitable phono turntable) to the phono preamplifier input terminals.
• DO NOT expose the unit to dripping or splashing.
• DO NOT place objects filled with liquids on the unit, e.g. vases.
• DO NOT place sources of naked flame on the unit, e.g. candles.
7PHONO PREAMPLIFIER
Front Panel Functions
1. DISPLAY LED
An LED on the front panel indicates that the power is on. When first switched on, the
display LED will immediately light and will remain lit during the time the preamplifier is
powered on.
Rear Panel Functions
This panel incorporates the terminals for connecting the input signal from a turntable,
outputs to the preamplifier, loading and gain switches and also the mains supply.
Please remember that your Plinius Koru Phono Preamplifier is a high quality electronic
instrument. Be sure that you understand your system’s requirements fully before you
make any connection to this phono preamplifier.
1. LOADING SWITCHES
The phono input capacitance and cartridge load can be adjusted to suit your
particular phono cartridge, using the 8-way mini-switches at the lower left of the
diagram. These switches can be used to set the input capacitance to 100pF or 570pF,
and the cartridge load to 22R, 47R, 100R, 220R, 470R, 1k, 22k or 47k.
2. GAIN SWITCHES
The phono gain can also be set to your phono turntable specifications using the
2-way mini-switches next to the loading switches. The Gain settings are 50dB, 56dB,
60dB or 66dB.
3. INPUT TERMINALS
The input terminals of your Plinius Koru Phono Preamplifier are easily accessible at
the lower right channel side of the rear panel.
RCA INPUTS LEFT & RIGHT: These standard RCA terminals are for use with
unbalanced signals from Turntable.
1 2
3 5 6
7
4
1
8 PLINIUS KORU
4. EARTH POST
This is a chassis connected gold-plated earth post for use with most vinyl turntables.
5. OUTPUT TERMINALS
Connections for line level preamplifiers are provided in the centre of the rear panel.
Connections are available for both single ended RCA and balanced XLR cables.
The XLR output pin configuration used in all Plinius product is:
PIN 1 to GND
PIN 2 to +Signal
PIN 3 to –Signal
NOTE: Because of the way balanced XLR outputs are configured it is not possible to
connect both XLR and RCA at the same time.
6. MAINS SWITCH
The heavy-duty rocker switch on the right of the panel diagram turns the Mains/
Line Power to the preamplifier ON or OFF. For your safety, this switch should remain
accessible at all times in case of an emergency.
7. MAINS POWER CORD IEC CONNECTOR
This connector is where the mains supply cable from your wall connects to the
preamplifier. You will notice that a fuse holder is mounted within this connection, and
it holds a mains fuse to provide surge and overload protection for your preamplifier.
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