Naim Audio NAC-N 172 XS - Manual (Page 35)

E33
NAP 500 Power Amplifier
31.1 General Connections Notes
The negative input and output connections for each
channel are common. The mains earth (ground) should
always be connected regardless of what other equipment
is used in conjunction with Naim power amplifiers. This only
grounds the case and the electrostatic screen within the
transformer, and is not connected to the signal negative. In
order to avoid hum loops, the signal negative of the whole
system should be connected to the mains earth (ground) in
one place.
Note: Each channel of the NAP 500 is a “bridged” amplifier,
so none of the speaker outlet sockets (+ or -) is at earth
potential. Avoid connecting mains powered equipment
such as electrostatic speakers, sub-woofers and headphone
energisers that do not have a floating earth. No plug which
is connected directly or indirectly to earth potential should
be attached to any speaker outlet (+ or -).
31.2 Protection Notes
In the NAP 500 the fan speed is increased in response to an
increase in amplifier dissipation. If the amplifier reaches 70°C
due to prolonged running at high level or to airflow being
blocked, the output will be interrupted and the fan will run
at full speed until it has cooled down. This may take a few
minutes.
It is not necessary to switch the amplifier off, but it may be
advisable to mute the preamplifier or turn the volume down
to avoid surprises when it comes back on.
OPERATION OF THE AMPLIFIER’S THERMAL PROTECTION
SUGGESTS PROLONGED USE AT TOO HIGH A VOLUME LEVEL.
YOUR LOUDSPEAKERS MAY BE AT RISK IF THIS IS THE CASE.
THE VOLUME SHOULD BE REDUCED.
31 Installation and Operation
The NAP 500 and NAP 500PS should be installed on a dedicated equipment stand
intended for the purpose and should be in their final location before connecting cables or
switching on. Switch on the source and preamplifier components, with the volume turned
down, before switching on the NAP 500. The NAP 500 power button is located on the front
panel of the NAP 500PS Power Supply.
Care should be taken when siting the NAP 500 to ensure that the top and bottom
ventilation grids are not blocked.
The NAP 500 and NAP 500PS are very heavy and care should be taken when lifting or
moving them. Make sure that the surface they are to be placed on can support the full
weight.
31.3 Loudspeaker Cable and Connectors
Only Naim Audio speaker cable should be used to connect
a loudspeaker to the output of the NAP 500. Custom Naim
Audio loudspeaker connectors are supplied to make the
connection and in order to comply with current European
safety regulations these should always be used.
DAMAGE TO THE AMPLIFIER MAY RESULT IF “HIGH DEFINITION”
CABLE OR ANY OTHER SPECIAL CABLE IS USED TO CONNECT
THE LOUDSPEAKERS.
Ensure when connecting speakers that they are “in phase”.
That is, the positive and negative connection orientation
at both the speaker and amplifier ends of the cable is the
same for both channels.