Musical Fidelity F225 User manual

Instructions For Use. Page 1F25
F25 REMOTE CONTROL STEREO
PREAMPLIFIER
INSTRUCTIONS FOR USE
Thank you for purchasing the Musical Fidelity
F25 Preamplifier. Used properly and carefully, it
should give you many years of outstanding musical
reproduction.
The F25 is the result of many years painstaking
research and development and is designed for
ultra-high definition performance. The F25 is
equipped with full remote control facilities.
The F25 operates in Class A. It has sound quality
equal to, or better than any preamplifier currently
available. We hope you will be delighted with your
purchase.
Dust regularly with a soft duster or soft brush but
do not use cleaning or polishing agents - they may harm
the surface finish.
If you have any questions about anything in your
audio system, please consult your dealer who is there
to help and advise you.

Instructions For Use. Page 2F25
PLEASE READ
IMPORTANT!
This unit is supplied in the UK with a mains lead fitted with a moulded 13 amp
plug. If, for any reason, you need to cut off this plug, please observe the following
safety precautions. Please dispose of the cut-off plug safely. It must not be plugged
into a mains power supply.
The wires in the mains lead supplied with this appliance are coloured in ac-
cordance 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 corre-
spond 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 termi-
nal 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 10 amp fuse must be used.
WARNING - Radio Frequency Interference (RFI)
This hi-fi product has been tested to ensure that its operation will not be ad-
versely affected by normal background levels of RFI. It is possible that if this prod-
uct is subjected to abnormally high levels of RFI the unit may be susceptible and not
perform as expected. In the unlikely event of this happening on a regular basis,
please contact Musical Fidelity's service department.
The unit has also been tested to ensure that it does not radiate excessive levels
of RFI that could affect other pieces of electronic or electrical equipment.
The electronics in modern hi-fi equipment is complex and hence may be dam-
aged by lightning. It is possible that during electrical storms the operation of some
equipment may be adversely affected. For complete protection of your hi-fi system
during such storms, mains plugs should be removed from sockets and aerial leads
disconnected.
Always ensure that when disconnecting and reconnecting your hi-fi equipment
the mains supply is switched off.

Instructions For Use. Page 3F25
þHeed all warnings on the back of
the unit.
þþ Place your F25 where there is
adequate ventilation.
þþ Only connect the unit to a power
supply of the type marked on the back
of the unit.
þþ Position the power supply lead
and signal interconnect leads where
they are not likely to be walked on or
trapped by items placed on them.
þþ Fit 2 x “AA” size batteries into
the remote control. These must be
alkaline types. Please observe the
correct polarity of + and - when fit-
ting.
ýý Do not use near water.
ýý Do not place the preamplifier
near direct heat sources such as radia-
tors or other equipment that produces
heat.
ýý Do not remove any covers or try
to gain access to the inside. The war-
ranty will be invalid if the unit has
been tampered with. There are no
user adjustments within. Refer all
service work to an authorised Musical
Fidelity agent.
ýý There are 3 fuses in the F25. In
the unlikely event that one blows, take
your F25 to your audio dealer. Do
NOT try to replace the fuse yourself
or you will invalidate the warranty.
BEFORE YOU SWITCH ON
You should make all connections to the F25 before switching on.
Follow this routine before you listen for the first time, and each time you
change any connections.
1Check all the inputs and outputs to the F25.
2Then check again.
3Turn the volume control to nil.
4Now you can switch on the power and carefully advance the volume to
the level you want and enjoy the music.
INSTALLATION
INSTALLATION PRECAUTIONS
Your new F25 is designed and built to provide trouble-free performance but it
is necessary to observe a few precautions. Please ensure that you have complied with
them before you connect any AC power to your amplifier. Retain this guide for
future reference.

Instructions For Use. Page 4F25
CONNECTIONS AND FACILITIES
REMOTECONTROL
AMute button
BVolume Up/Down buttons
CSourceselectorbuttons
FRONTPANEL
1Power indicator LED
2Power on/off switch
3Phonoinputselector
4CD input selector
5Tunerinputselector
6CDV input selector
7Tape input selector
8Aux input selector
9Remoterecieverlens
BACKPANEL
10 MovingMagnet (MM)Phono input
11 Phono/ChassisEarth
12 MovingCoil (MC)Phono input
13 CDinput
14 Tunerinput
15 CDVinput
16 Tape input
17 Auxiliaryunbalanced(RCA/phono)input
18 Auxiliarybalanced(XLR/Canon)input
19 Processorloop -inputfrom processor
20 Processorloop-outputtoprocessor
21 Tape record output
22 Unbalanced (RCA/phono) main outputs
23 IEC mains inlet/ fuseholder
24 Balanced (XLR/Cannon) main outputs
25 Auxilliaryinputtypeselector
26 MCloadingswitch
27 RIAA/IECEqualisationcurveselector
28 Phono input select MM/MC
29 MM loading dip switches
1 2 3 4 5 6 7 8 9
29 28 27 26 25 24 23
10
11 12 13 14 15 16 17 18 19 20 21 22
A
B
C

Instructions For Use. Page 5F25
CONNECTIONS
FOR THE BEST RESULTS:
We strongly recommend that you use the F16 or F19 power amplifiers manufac-
tured by Musical Fidelity.
These are designed for perfect electrical and sonic compatibility with the F25.
When paired, they produce truly extraordinary results which afford an unprecedented
level of musical communication, articulation and dynamics.
One of the design aims of the F25 was that it should be relatively insensitive to
the effects of interconnect cables. Although it is important that you use low imped-
ance, low capacitance cables, the exact make and model are not too important. Simi-
larly, a lot of fuss is made about different types of plugs and sockets; once again, the
F25 is very insensitive to these differences.
A large amount of time, effort, money and energy has been expended to ensure
that your F25 will produce optimal results with almost any cables or connectors. We
hope that this makes your installation and listening easier and more enjoyable.
CONNECTIONS
All connections should be made with the power off. The F25 has six inputs.
These are all clearly labelled on the back panel. The F25 also has a tape record out-
put. This should be connected to the input of a tape deck.
PHONO STAGE OPTIONS and SWITCHES
The phono input select toggle switch is used to select moving coil or moving
magnet input.
The push button marked equalisation is used to select the bass filtering of the
input. The original RIAA curve was modified some years ago by the IEC to include
an earlier bass roll-off, which prevents excessive cone movement with some speaker
systems. Ultimately, the choice of curve is up to you.
The toggle switch marked MC input loading is to select the impedance seen by
the moving coil cartridge, either 10 or 100 Ohms. MC cartridges are not particulalrly
sensitive to loading but you may find that one or the other setting suits your cartridge.
The dip switches are used to select the capacative loading on moving magnet
cartridges. This should be set by ear, as the total capacitance seen by the cartridge
will be dependent on the arm leads etc. Basically, up to a point, the higher the capaci-
tance, the smoother the sound. The left hand switch selects either 47KOhms or
68KOhms impedance. (47K normally)
LINE INPUTS
The five line inputs on the F25 are at the same level. The CD, tuner, CDV, tape
and aux. are all interchangeable, and any source with an output level in the The F25
must be connected to a power amplifier, such as the Musical Fidelity F16 or F19.
There are two pairs of sockets which can be used to output the signal from the preamp

Instructions For Use. Page 6F25
CONNECTIONS
to a power amp. One of these pairs are normal RCA type sockets. These are the
unbalanced outputs sometimes known as single ended outputs. The other pair of
sockets are the XLR balanced outputs. When the latter is used with a power ampli-
fier with balanced XLR inputs, benefits in terms of noise and dynamic range should
be apparent.
OPERATION
All operational functions of the F25, with the exception of the power on and
off, can be controlled via the supplied remote control.
To select any input, simply press the appropriate button on the remote control.
The volume control is motorised, so that when you press ‘+’ or ‘-’ on the remote, the
control will rotate in the required direction.
The LED in the volume control knob indicates the current setting of the control.
To temporarily turn off the sound, in order to answer the telephone for instance, press
the MUTE button on the remote control. The LED will change colour to red, indicat-
ing the muted state.
It is advisable to acquire the habit of turning down the volume to zero before
switch off.
EXTERNAL PROCESSOR CONNECTIONS
The F25 is fitted with external processor ‘out to’ and external processor ‘in
from’ sockets. As supplied, these will be connected by two shorting links. These can
easily be removed by simply pulling them out.
Note: When you do this the pre-amplifier and power-amplifier stages will
be separated, thus if no connection is made from 'out to' to 'in from' via a proc-
essor for instance no sound will be heard.
The most likely use of these sockets, would be to add a sound processor of some
kind to your system. This would be connected with its output to ‘input from’ on the
F25, and its input to ‘output to’. This device would then be permanently in the
circuit, and would affect the sound on all inputs.
Sound processors which are possible candidates for insertion are:-
·Surround Sound units.
·Digital Sound Processors (DSP)
·Graphic or Parametric Equalisers
·Impulse Noise Reduction Systems.
Please be aware that the potential to change the sound from that intended by the
producer of the recording is quite great with all of these devices, and that their pres-
ence in the circuit will degrade the sound quality of the system. The extent to which
this occurs will depend on the quality of the processor.

Instructions For Use. Page 7F25
CONNECTIONS
REMOTE CONTROL
The battery powered handheld remote control will perform the following func-
tions:
a. Mute
b. Volume control +/-
cInput selection
The mute control operates the output relay. When this control is used, the
output is muted and the dual colour LED in the volume control knob turns red.
When the mute button is pressed again, the output is unmuted and the LED turns
back to green.
The select and volume function buttons are self explanatory.
F25 LEDS
The F25 has three types of LED on the front panel:
a. Mains on/off (green)
b. Input indicator (red)
c. Status indicator (dual colour: red and green)
The on/off indicator is self explanatory. When the unit is switched on, the LED
is on.The input status indicator similarly. The LED above the input selected illumi-
nates.
The dual colour LED in the volume control knob is slightly more complex. It
has two functions. When switched on, it indicates the output relay status. Red for a
few seconds, then when the relay is open it turns green. There will be no output
from the F25 until this LED is green. The second function of the dual colour LED in
the volume control knob is to indicate mute status. When you press the mute button
on the remote control the F25 will mute and the LED will change to red. It will
remain this way until you press the mute button again when it turns back to green.
BALANCED/SINGLE ENDED OUTPUT MODE
The F25 can provide a balanced or a single ended out put. Simply plug your
leads into the XLR sockets for balanced operation, or plug your RCA phono leads
into the RCA phono sockets for single ended operation.
MUTE FUNCTION
The F25 remote control has a mute function. This cuts the output from the F25.
If, by mistake, you touch the mute button, there will be no output from the F25 and
you might think it has gone wrong. It hasn’t! Just press the mute button again until
the status LED turns green.

Instructions For Use. Page 8F25
Basic troubleshooting of an amplifier is similar to troubleshooting of any other
electrical or electronic equipment. Always check the most obvious possible
causes first. To give you a few ideas of what to look for, check the following:
TROUBLESHOOTING
Problem Probable Cause Remedy
No power when POWER
is pressed Mains plug not inserted correctly Plug in securely
Hum when listening to
turntable Incorrect earthing of pickup arm cable Either connect or disconnect the pick-up
arm earth wire to the
earth terminal on back
panel
No sound Volume control is set to
minimum Turn up the volume
"Mute" pressed on remote
control Press "mute" again
Power amplifier is not
connected Check cables and power amplifier
Speakers are not connected Check speaker cables
Wrong input is selected Check input selection
Sound is not precise,
lacking in bass and stereo
image
Speakers are connected out
of phase Make sure that both speakers are connected
correctly
Remote control operation
is not possible Amplifier's power switch is set to off Set switch to on
Batteries not inserted in
remote control unit Insert batteries
If none of these actions effect a cure, please contact your dealer, or an author-
ised Musical Fidelity service agent. Remember, never open the case of the F25
yourself, as this will invalidate the guarantee.

Instructions For Use. Page 9F25
SPECIFICATIONS
Improvements may result in specification or feature changes without notice.
Photos and illustrations may differ slightly from production models.
F25 REMOTE CONTROL PREAMPLIFIER
THD < 0.01%
Frequency response 20Hz - 20kHz +/- 1dB
Inputs 4 Line, Tape, Phono (MM/MC)
Input sensitivity Line (for 775mV out) 200mV
Input sensitivity Phono (for 775mV out) MM 3mV, MC 300mV
S/N Ratio : Line >85dB
: Phono MM >75dB
: Phono MC >60dB
Tape output Dependent on input level
Power consumption 10 Watts
Power requirements 100/115/230 Volts, AC 50/60Hz
(Factory Preset for country)
Dimensions 480 x 120 x 340mm (W x H x D)
Height includes feet
Weight 7.4 kgs. (unpacked)
9.5 kgs. (packed)
Standard accessories Remote Control Unit
Battery 2 x (SUM-4, “AA”,
“R03”)