NAIM POWERAMPS User manual

OWNERS MANUAL
Power Amplifiers

page
1.0 Equipment installation
Normally your Naim equipment will have been installed by the dealer who sold
it to you even if you live outside their immediate vicinity. Your dealer is
responsible for making sure that the system sounds exactly as it should and
information given here is not intended to reduce this responsibility in any way.
1.1 cables and connections
Please do not modify the standard interconnect cables supplied with your Naim
equipment. This is important for safety as well as performance. One end of each
cable is marked with a band to establish its correct orientation. The band always
marks the end that connects to the signal source.
Loudspeaker leads are also very important. Naim loudspeaker cable is correct for
your system and your dealer will make up leads to suit your equipment
installation. The leads should each be at least 3.5 metres long and of equal
length. The recommended maximum is 20 metres. Loudspeaker leads are, like
interconnect leads, directional, and should be connected so that the printed
arrow points towards the speakers. Using alternative loudspeaker cable will
degrade performance, and may even damage your amplifier. An exception to
these loudspeaker cable constraints is the nap 6-50 multi-room power
amplifier. The nap 6-50 is designed to be tolerant of both a wide variety of cable
types, and cable runs well in excess of 20m. The loudspeaker connectors supplied
with all Naim amplifiers and loudspeakers have been specifically designed to
make a robust mechanical connection. It is essential that these are used in order
to comply with current European safety regulations.
All the plugs and sockets supplied with your Naim equipment have been chosen
because they make the best possible connection for their purpose. A poor
contact will degrade the signal substantially and plugs and sockets should look
clean and free from corrosion. The easiest way to clean them is to switch off the
equipment, pull the plugs out of their sockets, and push them back in again.
Special contact cleaners and contact enhancers should not be used as they tend
to deposit a film which is very difficult to remove and may degrade the sound.
11.0 Equipment Installation
1.1 cables and
connections
2 2.0 Getting Started
2.1 switching on and off
2.2 running in
2.3 mains supply
2.4 siting the equipment
2.5 if you have a problem
3 3.0 Warnings
44.0 Connection
4.1 mains lead
4.2 non-rewireable mains
plugs
4.3 fuse carrier
4.4 plug fuses
5nap 500
7 nap 135
9nap 250, 180, 150 & 140
12 EC Declaration of Conformity
to Appropriate Standards
1

2.0 Getting Started
2.1 switching on and off
Source components and power supplies for cd players, tuners, preamplifiers and crossovers
should be switched on before switching on the amplifier(s). Always switch the amplifier(s)
off and wait about a minute for its power supply capacitors to discharge before
connecting or disconnecting any leads. Always use the power switch on the product rather
than a mains outlet switch.
2.2 running in
Your Naim equipment will take a considerable time to run-in before it performs at its best.
The duration varies, but under some conditions you will find that the sound continues to
improve for as much as five weeks. Better and more consistent performance will be
achieved if the system is left switched on for long periods. It is worth remembering
however that all electronic equipment can be damaged by lightning. Please read the
warnings section.
2.3 mains supply
Where fused plugs are used 13 amp fuses should be fitted. Fuses of a lower rating will fail
after a period of use.
A hi-fi system usually shares a mains circuit with other household equipment some of
which can cause distortion of the mains waveform. In some Naim equipment such
distortion can lead to a mechanical hum from the transformers. The hum is not
transmitted through the speakers and has no effect on the performance of the system but
is purely local to the transformer itself. A separate fused mains circuit (like that reserved
for electric cookers) may reduce transformer hum. Such a circuit (ideally with a 30 or 45
Amp rating) will also have a lower impedance, supply cleaner power, and consequently
improve system performance.
Do not wire voltage dependent resistors or noise suppressors into mains plugs. They
degrade the mains supply and the sound.
2.4 siting the equipment
Power supplies and amplifiers should be located a reasonable distance away from other
equipment. This separation will stop transformer radiation causing hum audible from the
loudspeakers. The minimum recommended distance is 300mm (12 inches), and that
allowed by the standard interconnect lead is the maximum.
Some Naim equipment is extremely heavy. Ensure than your equipment rack or table can
easily support the weight and is stable.
2.5 if you have a problem
Legal consumer protection varies from country to country. In most territories a dealer
must be prepared to take back any Naim equipment he has sold you if he cannot make it
work to your satisfaction in your own home. A problem may be due to a fault in any part
of the system or its installation so it is essential to make full use of your local dealer’s
diagnostic skills on site. Please contact your local distributor, or Naim at the address in
the back of this manual, if any difficulties cannot be resolved. Some Naim equipment is
made in special versions for different territories and this makes it impracticable to arrange
international guarantees. Please establish the guarantee arrangements with your own
dealer at the time of sale. We are always available to offer help and advice.
It is essential that repairs and updates are only carried out by an authorised Naim dealer,
or at the factory by Naim itself. Many components are made, tested or matched specially
for Naim and appropriate replacements are often unobtainable from non-specialist
sources.
2

important
In order to comply with current
European safety regulations it is
essential that the Naim loudspeaker
connectors supplied with amplifiers
and loudspeakers are used.
Do not under any circumstances
allow anyone to modify your Naim
equipment without first checking
with the factory, your dealer, or
your distributor. Unauthorised
modifications will invalidate your
guarantee.
For your own safety do not under
any circumstances open Naim
equipment without first
disconnecting the mains.
The following label is attached to
all mains powered equipment:
3.0 Warnings
Naim equipment is designed to offer the finest sound quality that can be achieved,
avoiding compromise wherever possible. This can lead to circumstances that may be
unfamiliar. The material that follows contains advice specifically related to Naim
equipment as well as more general warnings about the use of domestic audio products.
Please read it carefully.
The transformers in Naim power amplifiers and power supplies may sometimes make a
mechanical noise caused by distortion of the mains waveform. Naim transformers are
large in size and have heavy gauge secondary windings making them relatively sensitive
to such distortion. A separate mains circuit for your hi-fi system may reduce the effect
while also giving an overall improvement in sound quality. It may be necessary however
to take account of mechanical transformer noise when siting your equipment.
In some circumstances, depending on where you live and the earthing arrangements in
your home, you may experience radio frequency interference. Controls on broadcasting in
some territories allow very high levels of radio frequency radiation and both the choice
and exact siting of equipment may be critical. If there is a known problem in your locality
it is advisable to arrange for a home demonstration before purchase to find out if Naim
equipment is likely to be affected. Susceptibility to radio frequency interference is related
to the wide internal bandwidth necessary for high sound quality. Systems incorporating
moving coil phono preamplifiers and active crossovers are more likely to suffer. A radio
frequency filter kit is available for some Naim equipment but sound quality will be
progressively compromised as more elements of the kit are fitted. In situations of extreme
radio interference Naim equipment may be unsuitable.
Your Naim hi-fi system can be damaged by lightning. Power amplifiers are particularly at
risk and should be turned off when there is risk of lightning strike. For complete protection
all mains plugs and any aerial cables should be disconnected when not in use.
Equipment must not be exposed to dripping or splashing and no objects filled with liquid,
such as vases, should be placed on the equipment.
3

4.0 Connection
4.1 mains lead
As the colours of the wires in the mains lead of this apparatus may not correspond with
the coloured markings identifying the terminals in your plug proceed as follows:
The wire which is coloured GREEN-AND-YELLOW must be connected to the terminal in
the plug which is marked by the letter Eor by the safety earth symbol or coloured green
or green-and-yellow.
The wire which is coloured BLUE must be connected to the terminal in the plug which is
marked with the letter Nor coloured black.
The wire which is coloured BROWN must be connected to the terminal in the plug which
is marked with the letter Lor coloured red.
4.2 non-rewireable mains plugs
If a non-rewireable plug is cut from a mains lead (for whatever purpose) the plug MUST
be disposed of in a way to render it totally unusable. Considerable shock hazard exists if
the cut-off plug is inserted into a mains outlet.
4.3 fuse carrier
Should the plug fuse carrier be damaged or lost, the correct replacement must be obtained
from your dealer or from Naim direct. Do not use the plug until the fuse carrier is replaced.
4.4 plug fuses
Replace only with ASTA or BS 1362 approved fuses.
4
note
This equipment has been tested and found to comply with the relevant EMC and Safety Standards,
and, where applicable, also complies with the limits for a class B digital device, pursuant to Part
15 of the FCC Rules.
These limits are designed to provide reasonable protection against harmful interference in a
residential installation. This equipment generates, uses and can radiate radio frequency and, if not
installed and used in accordance with the instructions, may cause harmful interference to radio
communications. However, there is no guarantee that interference will not occur in a particular
installation. If this equipment does cause harmful interference to radio or television reception,
which can be determined by turning off and on, the user is encouraged to try to correct the
interference by one or more of the following measures:
• Reorient or relocate the receiving antenna.
• Increase the separation between the equipment and the receiver.
• Connect the equipment into an outlet on a circuit different from that to which the receiver is
connected.
• Consult your Naim dealer or an experienced radio/TV technician for help.

5
nap 500 power amplifier
connections
The negative input and output connections are all 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. This will normally be the turntable or cdplayer.
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 -).
protection
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.
siting
Care should be taken when siting the nap 500 to ensure that the top and bottom ventilation grids are
not blocked i.e. by carpet if the unit is to be placed on the floor.
weight
The nap 500 is very heavy and care should be taken when lifting or moving it. Make sure that the
surface it is to be placed on can support the full weight.
loudspeaker cable
For the best results Naim Audio’s own speaker cable should be used to connect a loudspeaker to the
output of the power amplifiers. Special Naim Audio loudspeaker connectors are supplied to make the
connection to the power amplifier(s). IT IS ESSENTIAL THAT THESE ARE USED, IN ORDER TO
COMPLY WITH CURRENT SAFETY REGULATIONS.
DO NOT, FOR ANY REASON, USE SO CALLED HIGH DEFINITION WIRE OR ANY OTHER SPECIAL
CABLE BETWEEN POWER AMPLIFIER AND LOUDSPEAKER AS DAMAGE MAY RESULT.

66
Specifications
nap 500
Standby power consumption (quiescent) 60VA
Working power consumption signal dependent
Power output, continuous 8 ohms 140 watts per channel
Voltage gain +29dB
Input impedance 18 kilohms
Frequency response -3dB@ 1.5Hz & 100kHz
Mains supply 100V. 115V. 230V - 50/60Hz
Case size (H x W x D)
nap 500 160 x 430 x 375mm
ps 500 76 x 430 x 300mm
Weight
nap 500 25kg
ps 500 15.4kg
nap 500 rear, connection to na ps500
na ps500 rear
- ++ -
-vech1
nc
Socket 1
-venc
ch2
Socket 2
2
1
mains input
to preamp power
supply. left, ch1
to preamp power
supply. right, ch2
left
loudspeaker ch1
right
loudspeaker ch2

7
nap 135 mono power amplifier
connections
The negative input and output connections are all 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. This will normally be in the turntable or cd player.
protection
In the nap135 power amplifier, fan speed is increased in response to an increase in amplifier
dissipation. If the heatsink of the 135 reaches 70°C due to either prolonged running at very high
dissipation, blocked airflow, or fan failure, the mains supply will be interrupted and the indicator light
will go off until the amplifier has cooled down. This may take up to thirty minutes. The regulated
power supply will shut down if more than 18amps is drawn for more than ten microseconds, but the
indicator light will not go off. To reset, turn the amplifier off for two minutes.
loudspeaker cable
For the best results Naim Audio’s own speaker cable should be used to connect a loudspeaker to the
output of the power amplifiers. Special Naim Audio loudspeaker connectors are supplied to make the
connection to the power amplifier(s). IT IS ESSENTIAL THAT THESE ARE USED, IN ORDER TO
COMPLY WITH CURRENT SAFETY REGULATIONS.
DO NOT, FOR ANY REASON, USE SO CALLED HIGH DEFINITION WIRE OR ANY OTHER SPECIAL
CABLE BETWEEN POWER AMPLIFIER AND LOUDSPEAKER AS DAMAGE MAY RESULT.
7

8
nap 135 rear, channel one - left
nap 135 rear, channel two - right
Specifications
nap 135
Power output
Continuous, 8 ohms 75 watts
Transient 500VA
Voltage gain +29dB
Input impedance 18 kilohms
Frequency response -3dB @ 3Hz & 50kHz
Mains supply 100V. 115V. 230V - 50/60Hz
Case size (H x W x D) 76 x 430 x 300mm
to power supply
mains input
left
loudspeaker ch1
fan
fan
to power supply
mains input
right
loudspeaker ch2
-vech1
nc
Socket 1
-venc
ch2
Socket 2
21
21
- +
- +

99
nap 140, 150, 180, 250 power amplifiers
connections
The negative input and output connections are all 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. This will normally be in the turntable or cd player.
protection
If the case of a nap 140, 150, 180 or 250 reaches 70°C due to prolonged running at high dissipation,
the mains supply will be interrupted and the indicator light will go off until the amplifier has cooled
down. This may take up to thirty minutes.
The regulated power suppplies in the nap 250 will shut down if more than 17 amps is drawn for more
than 10 microseconds but the indicator light will not go off. To reset, turn the amplifier off for one
minute.
loudspeaker cable
For the best results Naim Audio’s own speaker cable should be used to connect a loudspeaker to the
output of the power amplifiers. Special Naim Audio loudspeaker connectors are supplied to make the
connection to the power amplifier(s). IT IS ESSENTIAL THAT THESE ARE USED, IN ORDER TO
COMPLY WITH CURRENT SAFETY REGULATIONS.
DO NOT, FOR ANY REASON, USE SO CALLED HIGH DEFINITION WIRE OR ANY OTHER SPECIAL
CABLE BETWEEN POWER AMPLIFIER AND LOUDSPEAKER AS DAMAGE MAY RESULT.

10
nap 250 rear
nap 180 rear
Specifications
nap 250
Power output
Continuous, 8 ohms 70 watts per channel
Transient 400VA
Voltage gain +29dB
Input impedance 18 kilohms
Frequency response -3dB @ 3Hz & 50kHz
Mains supply 100V. 115V. 230V - 50/60Hz
Case size (H x W x D) 76 x 430 x 300mm
Specifications
nap 180
Power output
Continuous, 8 ohms 60 watts per channel
Transient 300VA
Voltage gain +29dB
Input impedance 18 kilohms
Frequency response -3dB @ 3Hz & 50kHz
Mains supply 100V. 115V. 230V - 50/60Hz
Case size (H x W x D) 76 x 430 x 300mm
to preamplifier or power supply
mains input
mains input
-ve
ch2
ch1
+ve
nap 180
-vech1
ch2
nap 250
left
loudspeaker ch1 right
loudspeaker ch2
+ - - +
left
loudspeaker ch1
right
loudspeaker ch2
+ - - +
to power supply

1111
nap 150 rear
Specifications
nap 150
Power output
Continuous, 8 ohms 50 watts per channel
Transient 250VA
Voltage gain +29dB
Input impedance 18 kilohms
Frequency response -3dB @ 3Hz & 50kHz
Mains supply 100V. 115V. 230V - 50/60Hz
Case size (H x W x D) 76 x 430 x 300mm
mains inputpower
to preamplifier or power supply
left
loudspeaker ch1
right
loudspeaker ch2
+ - - +
ch1
+ve
ch 2
-ve
nap 150
nap 140 rear
Specifications
nap 140
Power output
Continuous, 8 ohms 45 watts per channel
Transient 200VA
Voltage gain +29dB
Input impedance 18 kilohms
Frequency response -3dB @ 3Hz & 50kHz
Mains supply 100V. 115V. 230V - 50/60Hz
Case size (H x W x D) 76 x 205 x 300mm
to preamplifier or
power supply
mains input
-ve
ch2
+ve
ch1
nap 140
left
loudspeaker ch1
right
loudspeaker ch2
+ - - +

1212
Naim Audio Southampton Road Salisbury England SP1 2LN
Tel: [phone] www.naim-audio.com
OWNPA •issue 2 •May 2001
EC Declaration of Conformity to
Appropriate Standards
Manufacturer
Naim Audio Limited
Southampton Road
Salisbury England
SP1 2LN
Products
nap 500, 135, 250, 180, 150 and 140 power amplifiers
Safety
HD 195-S6
EN 60 065
EMC
Emissions Tested to EN 55013
Sound and television broadcast receivers and associated equiment
Immunity Tested to EN55020
Electromagnetic immunity of broadcast receivers and associated equipment
In accordance with CISPR 16-1
Radio disturbance and immunity measuring apparatus
CISPR 16-2
Methods of measurement of disturbances and immunity
IEC 801-2 8KV (air gap)
4KV (contact)
(performance criterion B)
IEC 801-3 3V/m 20dB
(performance criterion A)
IEC 801-4 1KV (AC lines)
0.5KV (signal lines)
(performance criterion B)