Nagra BPS Manual Del Usuario página 4

Package contents
In addition to the manual and the BPS, the box contains:
•
The "protocol", which documents the characteristics
of your unit, as measured in our laboratory
•
6x load circuits for moving coil (MC) cartridges
•
2x Allen keys (silver and black)
•
1x 9V battery
Please contact your Nagra dealer if anything is missing.
Powering the BPS
To install the battery, put the front panel selector in the OFF
position. Open the cover (1) with the silver Allen key.
You can check the battery charge level by switching the front
panel selector (2) to "test". If the battery is sufficiently
charged, the LED must be bright red.
The BPS will operate for around 100 hours with one alkaline
battery.
The BPS has been designed to work with a disposable or
rechargeable battery. A forthcoming, specific Nagra power
supply will make use of the DC-INPUT connector. Please
contact your Nagra dealer for details.
Positioning
The BPS should be placed as close as possible to the record
deck, using the shortest possible cables. Please also keep it as
far from mains cables as possible.
Opening the casing
Remove the battery compartment cover (1). Then, remove
the four screws (4) of the top cover using the silver Allen key.
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BPS
MM or MC cartridge
The BPS is preset to operate with an MC (moving coil)
cartridge. In order to use an MM (moving magnet) cartridge,
internal jumpers must be moved (see diagram D).
MM input impedance
By default, the input impedance of the BPS when set to MM is
47 Kohms and 100pF. Taking into account the capacity of the
cable that links the tone-arm to the BPS, the overall
impedance from the cartridge will be in the 100 to 200 pF
range, matching the optimum load for MM cartridges.
MC cartridges load circuits
The BPS is supplied with various load circuits, allowing its input
impedance to be matched as closely as possible to the
recommended value for your cartridge (this value should be
indicated in the specifications of your cartridge).
Insert the load circuit and secure the screw using the black
Allen key (see diagram B).
If the exact value recommended for your cartridge is not
provided, select the closest value above it in the above table,
load in Ohms.
Symmetric or asymmetric
For moving coil cartridges, operation is possible in symmetric
or asymmetric mode. In the absence of hum problems, the
asymmetric mode should be selected (this is the default
setting).
You can switch mode by moving the S1 and S5 jumpers as per
the following diagrams:
E asymmetric
F symetric
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BPS