E10
14.1 General Connections Notes
The negative input and output connections are all common. The
mains earth should always be connected regardless of what
other equipment is used. 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.
14.2 Protection Notes
If the amplifier’s external case reaches 70°C due to prolonged
running at high power, the mains supply will be interrupted and
the illuminated logo will switch off until the amplifier has cooled
down. This may take up to thirty minutes.
14 NAP 155 XS Installation and Operation
The NAP 155 XS should be installed on a dedicated equipment stand intended for the purpose
and should be in its 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 155 XS. The NAP 155 XS power switch is located on the rear panel.
The NAP 155 XS can provide power for an appropriate Naim Audio preamplifier. The power
supply output is carried on the DIN input socket.
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.
14.3 Loudspeaker Cable and Connectors
Only Naim Audio speaker cable should be used to connect a
loudspeaker to the output of the NAP 155 XS. 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.
mains input
and fuse
signal input
ch1(L) & ch2(R) and
preamp power supply
ch2
ch1
24V
0.25A
Input/Preamp
Power Socket
-ve
power
switch
NAP 155 XS
15 NAP 155 XS Connections
15.1 NAP 155 XS Rear
left
speaker
right
speaker
Note:
The NAP 155 XS features various technologies to reduce
microphonic effects. Some movement of the board and sockets
when connecting and disconnecting cables is normal.
