Musical Fidelity kW 750 User manual

Issue 1 : January 2005 kW Phono Pre-Amplifier Instructions for use Page 1 of 7
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kW Phono
PHONO PREAMPLIFIER
INSTRUCTIONS FOR USE
Thank you for purchasing the Musical Fidelity kW Phono preamplifier.
Used properly and carefully, it should give many years of outstanding musical
reproduction.
Aesthetically, the kW Phono is a perfect match for the
kW 750 Power Amplifier, kW Hybrid Line Level Preamplifier
and kW SACD Player.
Together they form one of the finest hi-fi systems available.
Dust regularly with a soft duster or soft brush, but be careful when using cleaning
or polishing agents - they may harm the surface finish.
If you have any questions about your audio system,
please consult your dealer who is there to help and advise.

Issue 1 : January 2005 kW Phono Pre-Amplifier Instructions for use Page 2 of 7
SAFETY INFORMATION
IMPORTANT!(U.K. only)
This unit is supplied in the U.K. with a mains lead fitted with a moulded 13 amp plug. If, for any
reason, you need to cut off the plug, please remove the fuse holder and dispose of the plug safely,
out of reach of children. It must not be plugged into a mains outlet.
The wires in the mains lead supplied with this appliance are coloured in accordance with the
following code: Green and yellow..............Earth
Blue................................Neutral
Brown.................................Live
WARNING - This appliance must be earthed
As the colours of the wires of the mains lead of this appliance 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 with the letter E or coloured green or green-and-yellow, or by the earth symbol:
The wire which is coloured brown must be connected to the terminal which is marked with the
letter L or coloured red.
The wire which is coloured blue must be connected to the terminal which is marked with the letter
N or coloured black.
If connecting to a BS1363 plug, a 13 amp fuse must be used.
WARNING:
Any modifications to this product not expressly approved by Musical Fidelity who
is the party responsible for standards compliance could void the user’s authority to
operate this equipment.

Issue 1 : January 2005 kW Phono Pre-Amplifier Instructions for use Page 3 of 7
GENERAL ADVICE
INSTALLATION PRECAUTIONS and USER INFORMATION
Your new kW Phono is designed and built to provide trouble-free performance, but as with all
electronic devices it is necessary to observe a few precautions:
Heed all warnings shown on the back of the product.
Only connect the kW Phono to a mains outlet having the same voltage as marked at the back of the
unit.
Always ensure that when disconnecting and reconnecting your audio equipment the mains supply
is switched off.
Position the mains lead and signal interconnects where they are not likely to be walked on or
trapped by items placed on them.
Do not use near water, or place water-filled containers on the pre-amplifier, for example, a flower
vase or potted plants. If water does spill inside, immediately pull out the mains plug from the
wall socket and inform your dealer, who should then check the unit before further use.
Entry of liquid into the preamplifier is dangerous, and may cause electric shock or fire
hazard.
Do not place the unit near direct heat sources such as radiators, direct sunlight or other equipment.
Do not remove any covers or try to gain access to the inside. There are no internal adjustments or
fuses you can replace yourself. Refer all service work to an authorised Musical Fidelity agent.
Note: Unauthorised opening of the equipment will invalidate any warranty claim.
Dust regularly with a soft cloth or soft brush but be careful when using cleaning or polishing agents
- they may harm the surface finish.
The electronics in modern hi-fi equipment is complex and may, therefore, be adversely affected or
damaged by lightning. For protection of your audio system during electrical storms, remove the
mains plugs and disconnect any aerial lead.
If after-sales service is required, to help your dealer identify the kW Phono pre-amplifier please
quote the serial number located on the rear panel of the unit.
RADIO FREQUENCY INTERFERENCE (R.F.I)
This product has been tested to ensure that its operation is not adversely affected by normal
background levels of R.F.I., and that it does not itself generate excessive amounts of interference.
However, if a problem persists, please contact your Musical Fidelity agent.

Issue 1 : January 2005 kW Phono Pre-Amplifier Instructions for use Page 4 of 7
CONNECTIONS and FACILITIES
1 2 3 4 5 6 7 8 9 1
FRONT PANEL
1 Illuminated feet with multi-colour
indicator LEDs (see page 6)
2 POWER mains on/off push switch
3 Power on indicator LED
4 Moving Magnet/Moving Coil
input selection button (see page 6)
5 Moving Magnet input indicator LED
6 Moving Coil input indicator LED
7 RIAA compensation indicator LED
8 IEC compensation indicator LED
9 RIAA/IEC compensation selection button (see page 6)
REAR PANEL
10 Moving Coil input socket - right channel
11 Moving Magnet input socket - left channel
12 Moving Coil input socket - left channel
13 Mains inlet socket - IEC type (10 Amp)
14 Moving Magnet input socket - right channel
15 Moving Magnet impedance selection switch
- right channel (see page 6)
16 Moving Coil LOADING selection switch
- right channel (see page 6)
17 Phono chassis earth terminal
18 Moving Magnet impedance selection switches
- left channel (see page 6)
19 Moving Coil LOADING selection switch
- left channel (see page 6)
20 Audio output socket - RIGHT channel
21 Audio output socket - LEFT channel
101112 13
14 15 16 17 18 19 20 21

Issue 1 : January 2005 kW Phono Pre-Amplifier Instructions for use Page 5 of 7
CONNECTIONS
All input, output and power connections
should be made with the mains power
switched OFF.
INPUT CONNECTIONS
The rear panel of your kW Phono pre-
amplifier has two pairs of phono input
sockets, one pair for left and right moving
magnet (MM) and the other pair for moving
coil (MC) pickup cartridges.
(See also page 6, MM / MC switching).
Two sets of switches located on the rear panel
are for optimising phono performance as
follow:
MC (only):
Input loading can be changed as required by
sliding the LOADING switch underneath the
PHONO MC input socket between the 100
Ohms and 10 Ohms options. Both positions
have an input capacitance of 470pF.
MM (only):
A four-way switch underneath the PHONO
MM input socket is for matching the
characteristics of your phono pickup and lead
to the kW Phono. When all the switches are
off (up), the input impedance is 68K Ohms in
parallel with 47pF capacitance.
When each individual lever is moved
downwards, loading of the MM phono input
circuit changes as shown by adjacent graphics
on the rear panel (see also specification on
page 7). If you are not sure which
combination to select, please consult your
dealer.
Some turntables or pickup arms are fitted with
an extra wire for chassis earthing. This
should be connected to the chassis earth
terminal on the back panel.
(Note : this is not a safety earth).
OUTPUT CONNECTIONS
The kW Phono has two line level audio
outputs from RCA sockets on the back panel,
marked OUTPUTS. Using good quality
RCA co-axial audio leads, connect the left
and right outputs to the pre-amplifier input of
your audio system.

Issue 1 : January 2005 kW Phono Pre-Amplifier Instructions for use Page 6 of 7
OPERATION
BEFORE SWITCHING ON . . . . .
Plug the accessory IEC mains lead into the
rear panel socket, then the other end into a
convenient wall outlet.
STARTING
Press the POWER switch button on the
preamplifier front panel - the blue LED just
above the button will light indicating that
power is applied to the unit.
LEDs in the support feet will also light red for
about six seconds, indicating that both left
and right audio outputs are muted.
Muting is then disabled, and feet illumination
then fades over approximately fifteen seconds
to yellow, showing that your kW Phono is
now ready for use.
After a period of about 35 minutes, the LED
feet colour fades to blue, confirming that the
pre-amplifier is fully warmed up.
PHONO MM / MC SWITCHING
Your kW Phono preamplifier has independent
circuits for moving magnet (MM) or moving
coil (MC) phono pickups.
To obtain the preferred input, press the MM /
MC selector button on the front panel. A
corresponding blue indicator on the front
panel will light to confirm your selection.
Each press of the button changes over input
between the two options.
CAUTION - only operate this function at low
volume setting.
RIAA / IEC COMPENSATION
As a further refinement, the phono pickup
characteristic can be adjusted to suit either
RIAA or IEC compensation curves.
Historically, the original RIAA curve defined
the low audio frequency limit as 20Hz.
The later IEC standard specifies frequency
response down to 10Hz to restrict possible
turntable rumble, or the effect of a warped
record.
Each time the RIAA/IEC button on the front
panel is pressed, the phono pickup stage is
switched alternately between the two options.
A corresponding blue indicator on the front
panel lights up to confirm your choice.

Issue 1 : January 2005 kW Phono Pre-Amplifier Instructions for use Page 7 of 7
kW Phono
PREAMPLIFIER .SPECIFICATIONS.
Output :
Voltage RMS, maximum > 43 Volts
Impedance 32 Ohms
Frequency response deviation from RIAA 20Hz to 20kHz ±0.1dB
Input :
Total harmonic distortion + noise, < 0.012% (MM, 10 Volts output)
20Hz to 20kHz
Input sensitivity for 300mV RMS output 2.9mV Moving Magnet, 500µV Moving Coil
Input impedance MC : Switched, 10 Ohms or 100 Ohms in parallel with 470pF
MM : All switches up : 68k Ohms in parallel with 47pF,
Switch no. 1 down : 47k Ohms + 47pF,
Switch no. 2 down : extra 50pF added,
Switch no. 3 down : extra 100pF added,
Switch no. 4 down : extra 200pF added
Overload margin 42dB above rated input at 1kHz (MM)
Channel separation > 64dB 20Hz to 20kHz
Channel balance error < 0.5dB typical
Signal / noise ref. 1Volt RMS output > 78dB Moving Magnet (“A”-weighted)
> 75dB Moving Coil (“A”-weighted)
Frequency response reference IEC, RIAA
- see graph . . . .
Input sockets : 2 phono Moving Magnet via RCA connector
2 phono Moving Coil via RCA connector
Output sockets : 2 RCA connectors for line level output
Power requirements : 115 /230 Volts or 100 V AC 50 /60Hz (factory preset)
25 watts maximum
Dimensions : 483mm, 19 inches wide
167mm, 6.6 inches high (including feet)
456mm, 18 inches deep (including buttons and rear terminals)
Weights : 18.15Kg, 40 lbs unit only, unboxed
23Kg, 51 lbs in shipping carton
Standard accessories : IEC mains lead - 10 Amp type
Musical Fidelity reserves the right to make improvements which
may result in specification or feature changes without notice
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RIAA
PHONO
RIAA/IEC
PHONO RESPONSE
Frequency (Hz)
dB