Nagra CLASSIC PHONO User manual

P/N: 2055034159
All rights reserved –© 2020 rev1
CLASSIC PHONO
User manual

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Nagra –CLASSIC PHONO
Table of contents
Safety warning .....................................................................................................3
Warranty..............................................................................................................3
Congratulations....................................................................................................4
Package contents.............................................................................................4
Installation............................................................................................................5
Positioning........................................................................................................5
Powering the Nagra CLASSIC PHONO............................................................6
Connecting the Mains.......................................................................................6
Connecting the Nagra CLASSIC PSU...............................................................6
Connection block on rear panel ........................................................................7
Front panel.......................................................................................................8
Operations ...........................................................................................................9
Basic operations...............................................................................................9
Nagra Modulometer..........................................................................................9
Light intensity adjustment ...............................................................................10
Curve selection...............................................................................................10
Mono cartridge LED........................................................................................10
Mono/stereo mode selection...........................................................................11
Gain selection.................................................................................................11
Input setting .......................................................................................................12
Open/close the Nagra CLASSIC PHONO.......................................................12
Factory settings..............................................................................................13
Jumpers & switch functions ............................................................................14
Load circuits ...................................................................................................15
Load circuit installation....................................................................................15
External transformer usage.............................................................................16
Maintenance ......................................................................................................17
Tube ageing ...................................................................................................17
Case cleaning.................................................................................................17
Technical specifications .....................................................................................18
De-emphasis curves.......................................................................................20
Declaration of conformity....................................................................................21

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Nagra –CLASSIC PHONO
Safety warning
Read this manual carefully before operating the Nagra CLASSIC
PHONO;
Should you have any questions on how to setup or use your Nagra
CLASSIC PHONO, please contact your Nagra dealer;
Audio Technology Switzerland SA declines any responsibility in the
event of an accident caused by the non-observance of these
instructions or any other form of user negligence;
The Nagra CLASSIC PHONO is a CLASS I equipment. It is essential
that it is connected to a Mains socket outlet with a protective earthing
connection when using the AC power supply;
Never try to open your Nagra CLASSIC PHONO when it is powered to
prevent the risk of electric shock and burns. Switch it OFF, remove the
Mains or the external DC power supply cable from the back panel and
wait at least 10 minutes before any intervention into your Nagra
CLASSIC PHONO such as for tube exchange or input module
adjustments. If you are unsure, please contact your Nagra dealer.
Warranty
Audio Technology Switzerland SA certifies that this device has been inspected
and tested before leaving the factory.
Every Nagra unit goes through our test laboratory. The result of the
measurements is recorded in the “Protocol” documentation that comes with your
device.
We guarantee our products against all manufacturing defects, for a period of three
years for the Nagra CLASSIC PHONO and six months for the tubes, running from
the date of delivery to the customer (validated by the serial number on the device
casing and the invoice from an official Nagra dealer). This warranty is only valid
for the original purchaser of new equipment.
This limited warranty covers the repair and replacement of defective parts,
excluding any other remedy.
The absence of a serial number invalidates the warranty.
We decline any responsibility for damages resulting directly or indirectly from the
use of our products and from the use of any components or spare parts other than
those designated as original/approved parts by Audio Technology Switzerland
SA.
As we constantly strive to improve our products, we reserve the right to modify
them or change their specifications without notice.

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Nagra –CLASSIC PHONO
Congratulations
Congratulations! You have just acquired one of the best ever phono preamplifiers.
The Nagra CLASSIC PHONO was created by an engineering team with more
than 60 years’ experience designing world-class products for the professional
audio, national security and military businesses.
Ever since its creation in 1951, Nagra builds devices that offer exceptional sonic
performance. The company has received many awards for its technical
innovations and the excellence of its products. Among the most prestigious,
Nagra has been awarded two Oscars® and two Emmy®.
The professional and Hi-Fi ranges are designed by the same Research and
Development department. Nagra has launched a Hi-Fi range to allow the wider
public to benefit from technical advances that are often the privilege of the
professionals.
This technology exists in the service of music, your music. This is why we already
wish you some great moments of listening pleasure with your Nagra CLASSIC
PHONO.
Thank you for your trust.
Package contents
Besides the manual and the Nagra CLASSIC PHONO itself, the box contains:
Mains cable*;
Record of measurements, response curve characteristics for your
device, measured by the Nagra laboratory;
Pair of “Haute Horlogerie” grade microfiber gloves;
Allen key to open the top panel;
12 black plastic jumpers;
6 load circuits in their box;
2 spacer screws to secure the load circuit;
Please contact your Nagra dealer if anything should be missing.
* Depending on the country of purchase, the cable supplied by Nagra will feature
an European, Swiss or US plug.

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Nagra –CLASSIC PHONO
Installation
Positioning
The Nagra CLASSIC PHONO must not be exposed to dripping or splashing
liquids and no objects filled with liquids, such as vases, should be placed on the
machine. Use exclusively indoors in a moderate climate.
There must be enough space all around the chassis for adequate ventilation.
Ventilation should not be impeded by covering the ventilation openings with items
such as newspapers, table-cloths, curtains, etc.
The Nagra CLASSIC PHONO must rest on a stable support. We recommend that
you use the anti-vibration support, the Nagra CLASSIC VFS FOR SOURCE,
Vibration Free Support for source, developed by Nagra consisting of isolated solid
aluminum plates using the same silicon base damping material as the Nagra CD
mechanics.

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Nagra –CLASSIC PHONO
Powering the Nagra CLASSIC PHONO
The Nagra CLASSIC PHONO can be powered either by its own internal power
supply or by an external 12 V with the Nagra CLASSIC PSU.
The Nagra CLASSIC PHONO can not be powered by a Nagra MPS due to its
power consumption.
In the first case, simply use the AC Mains cable provided.
Connecting the Mains
Place the Mains power switch on the rear panel of the
unit in the OFF position, marked “O”.
Insert the C13 IEC connector of the power cable into the
C14 IEC Apliance inlet of the Nagra CLASSIC PHONO.
You may then push the Mains switch into the “I”
position.
Fuse replacement
The fuse holder includes a replacement fuse.
The fuse type is:
FST 5x20mm 250V / T 500mA L.
Should you need to replace it, only use the
same fuse type.
Connecting the Nagra CLASSIC PSU
Start by removing the IEC power cable from the IEC
Appliance inlet of the Nagra CLASSIC PHONO. The
Mains switch position is no longer relevant when an
external power supply is connected.
Place the front panel selector in the OFF position. Insert
the LEMO connector from the external power supply
cable into the DC socket as shown beside. You will hear
a click that indicates the connector is securely locked in.
Only use a LEMO cable with BLACK & BROWN
sleeves to benefit from the best CLASSIC PSU
features. The BLACK-sleeved LEMO plug should be
connected to the Nagra CLASSIC PSU.
To disconnect the LEMO plug, hold
the fluted section of the connector and
pull it backwards.
C13 IEC
connector

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Nagra –CLASSIC PHONO
Connection block on rear panel
5.
6.
1.
2.
3.
4.
7.
1.
Input PHONO 1
2.
Input PHONO 2
3.
Output block with 2x XLR and 2x RCA*
4.
Ground connector
5.
Ground connector (phono)
6.
DC input on LEMO socket
7.
Mains connector, fuse & switch
*Use either RCA or XLR, but not both simultaneously.
The XLR connectors are unbalanced.
In order to obtain optimal performance from the Nagra CLASSIC PHONO, it is
preferable to leave the device switched on for about 15 minutes before use, so
that the internal components can reach their optimum operating temperature.
Like all tube electronic devices, the Nagra CLASSIC PHONO needs a running-in
period. It will reach peak performance after a few hundred hours operation.
Note about the Ground connectors
This feature is seldom used but often handy to solve specific setup issues. Your
Nagra dealer will assist you on when and how to use these connectors.

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Nagra –CLASSIC PHONO
Front panel
1.
2.
3.
4.
5.
6.
7.
1.
Modulometer intensity switch, pushed up will increase the intensity, down
will reduce it, there are 7 intensity levels
2.
Nagra Modulometer indicates the output level in dB, reference 0 dB = 1 V
3.
De-emphasis curve selection
4.
Mono cartridge LED
5.
Mono/stereo mode selection
6.
Gain selection:
Low position MM 38 dB / MC 54 dB,
High position +10 dB (MM 48 dB / MC 64 dB)
7.
Front rotary selector
When turned ON, the CLASSIC PHONO will go through a 2 minutes preheating
phase with the Mono cartridge LED blinking. This is in order to optimize the
warming-up of tubes and critical components. This will allow your CLASSIC
PHONO to offer excellent performance for a longer period, the components
managed gently.
Note: In case of an accidental return to the OFF position for less than 2
seconds, the preheating is not reapplied.

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Nagra –CLASSIC PHONO
Operations
Basic operations
The typical Nagra front rotary selector offers 4 positions.
The OFF is equivalent to STANDBY. The unit is still powered
but with very little power consumption.
MUTE, the unit is ON but the audio signal is muted.
PHONO 1, the unit is fully operational on the input PHONO 1.
PHONO 2, the unit is fully operational on the input PHONO 2.
WITH AC POWER
WITH DC POWER
Rear
Mains
switch
CLASSI
C PSU
output
Front
rotary
selector
Action
0
OFF
Any
The unit is totally off
I
ON
OFF
The unit is in standby
I
ON
MUTE
The unit is on and muted (warming-up for
instance)
I
ON
PHONO 1
The unit is fully operational on the input
PHONO 1
I
ON
PHONO 2
The unit is fully operational on the input
PHONO 2
Nagra Modulometer
Nagra Modulometer is inherited from the
second recorder developed by Nagra back in
1952, the Nagra II. The Modulometer is a
typical Nagra precision instrument that
displays the necessary information to perform
the best possible listening. In the case of the
Nagra CLASSIC PHONO, the Modulometer
displays the output level. The 0 dB
corresponds to a 1 V rms signal on the output.
Left channel - black needle
Right channel - red needle
The Modulometer allows you to make sure you select the input setting in a
consistent manner with the source/cartridge you are using.

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Nagra –CLASSIC PHONO
Light intensity adjustment
This two-way toggle switch allows you to adjust the
Modulometer backlight intensity. Pushing the toggle
up will increase the intensity, pushing it down will
lower the intensity all the way to complete extinction.
In total there are 7 different levels.
Curve selection
This 3 positions switch allows you
to select the desired de-emphasis
curve.
Mono cartridge LED
This LED switches ON when the
switch (7) on the cartridge setting
board of the selected input is set on
position A.
Note:
Only use this setting with a monoral
cartridge installed on the turntable.
The LED is blinking during the
preheating phase.