Musical Fidelity A308 CR User manual

A308 CR Power Instructions for Use Page 1of 7
Issue 3: March 2003
A308CR
DUAL MONO POWER AMPLIFIER
INSTRUCTIONS FOR USE
Thank you for purchasing the Musical Fidelity A308 CR Power amplifier.
Used properly and carefully, it should give you many
years of outstanding musical reproduction.
Aesthetically, the A308 CR Power amplifier is a perfect match
for the A308 CR Preamplifier and A308 CR CD player.
Together, they form one of the finest hi-fi systems available today.
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.
MUSICAL FIDELITY A308CR
DUAL MONO POWER AMPLIFIER
POWER INPUT SELECTOR
A B

A308 CR Power Instructions for Use Page 2of 7
Issue 3: March 2003
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 this 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:
The A308 CR is a powerful amplifier and must necessarily supply high voltages
through the loudspeaker terminals. Therefore, to avoid any possibility of an
electric shock DO NOT TOUCH THE SPEAKER TERMINALS when the unit is
being used.
To comply with BSEN60065 safety regulations, the 4mm “banana” plug holes have
been fitted with plastic blanking pieces. Removal of these will invalidate any elec-
trical safety approval of this product.
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.

A308 CR Power Instructions for Use Page 3of 7
Issue 3: March 2003
GENERAL ADVICE
INSTALLATION PRECAUTIONS and USER INFORMATION
Your new A308 CR power amplifier 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 A308 CR amplifier 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 amplifier, for example, flower
vases 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 amplifier is dangerous, and may cause electric shock or fire hazard.
Do not place the unit near heat sources such as radiators, direct sunlight or other equipment.
The case of this amplifier can run at high temperatures - operate the unit in a well ventilated
area, and do not touch the side heatsink fins after periods of use at high output power.
Do not remove covers or try to gain access to the inside. There are no internal user adjust-
ments. Refer all service work to an authorised Musical Fidelity agent.
NOTE: Unauthorised opening of the equipment will invalidate any warranty claims.
There are fuses inside the A308 CR amplifier. In the unlikely event that one blows, refer the unit
to your audio dealer. Do NOT try to replace the fuse yourself as this will invalidate the war-
ranty.
Dust regularly with a soft duster 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 A308 CR 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 interfer-
ence. However, if a problem persists, please contact your Musical Fidelity agent.

A308 CR Power Instructions for Use Page 4of 7
Issue 3: March 2003
CONNECTIONS AND FACILITIES
MUSICAL FIDELITY
A308 DUAL MONO POWER AMPLIFIER
C R
MANUFACTURED IN ENGLAND BY MUSICAL FIDELITY
POWER
CONSUMPTION
1000W
THIS APPLIANCE
MUST BE
EARTHED
IMPORTANT
50/60Hz
MOUNT UNIT ON SOLID SURFACE.
DO NOT REMOVE SCREWS OR COVERS UNDER ANY CIRCUMSTANCES.
NO USER SERVICEABLE COMPONENTS INSIDE.
REFER SERVICING TO QUALIFIED ENGINEER.
SEE OWNERS MANUAL FOR FURTHER INFORMATION. CC
RIGHT CHANNEL LEFT CHANNEL
INPUTA
INPUT B
LOOP OUTPUT LOOP OUTPUT
INPUT B
INPUTA
+
CAUTION
RIGHT SPEAKER
OUTPUT
+
--
LEFT SPEAKER
OUTPUT
++
-
-
6 789 10 11 12 13 14
Front panel layout
1Power on indicator LED
2Power on/off switch
3Input A indicator LED
4Input selector button
5Input B indicator LED
(see page 5)
Back panel layout
6Right speaker output
7Right loop output (see page 5)
8Right input “A”
9Right input “B”
10 Left input “B”
11 Left input “A”
12 Left loop output (see page 5)
13 Left speaker output
14 IEC mains inlet
MUSICAL FIDELITY A308CR
DUAL MONO POWER AMPLIFIER
POWER INPUT SELECTOR
A B
1 2 345

A308 CR Power Instructions for Use Page 5of 7
All input, output and power connections
should be made with the mains power
switched OFF.
INPUT CONNECTIONS
The A308 CR power amplifier can be used
with a preamplifier or any line level source
which has a volume control. We highly
recommend the matching A308 CR pream-
plifier available from Musical Fidelity.
There are two audio inputs on the amplifi-
er, Aand B, which are selected by a push-
push switch located at the right-hand end
of the front panel.
Using good quality co-axial audio leads,
connect the left and right outputs from
your pre-amp or other line level source to
either Aor Bof the two RCA socket input
groups on the back panel marked as LEFT
and RIGHT CHANNEL INPUT.
The LOOP OUTPUT sockets are elec-
tronically routed inside the unit to dupli-
cate whichever of the Aor Bline inputs
has been selected for speaker output by the
A308 CR. This is to enable onward con-
nection to another amplifier, for example
when used for “bi-amplification”.
Issue 3: March 2003
LOUDSPEAKER CONNECTIONS
All connections should be made with the
power OFF.
Connect your loudspeakers to the loud-
speaker terminals situated on the back panel
marked as LEFT and RIGHT SPEAKER
OUTPUT. Two pairs are provided for con-
venience, but note that the combined load
impedance must not be less than 4 ohms
for either channel.
BEFORE SWITCHING ON. . . . .
Plug the accessory IEC mains lead into the
rear panel socket, then the other end into a
convenient wall outlet.
Turn the volume control on your preampli-
fier to minimum, and switch on its power.
OPERATION
Press the POWER switch on the front
panel of the A308 CR - the blue POWER
LED will light to confirm that the unit is
ready for use.
Select either input Aor input Bby pressing
the selector button at the right-hand end of
the front panel. Each press of the button
alternates between Aand Binput.
Select the required audio input source on
your pre-amplifier, and advance the volume
control to obtain the preferred sound level.
CONNECTIONS and OPERATION

A308 CR Power Instructions for Use Page 6of 7
Issue 3: March 2003
PROBLEMS ?
Basic problem solving with an amplifier is similar to troubleshooting 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:
If none of these actions effect a cure, please contact your dealer, or an authorised Musical
Fidelity service agent. Remember, never open the case of the A308 CR Power amplifier your-
self, as this will invalidate the guarantee.
Problem Possible Cause Remedy
No power when MAINS Mains plug not inserted Plug in securely
POWER switch is operated fully into rear socket
No sound Tape monitor function has Switch off tape monitor
been selected on the pre- at the pre-amplifier
amplifier
Wrong connections between Check audio input lead
pre-amplifier and the A308 CR connections
Speakers not connected, or Check speaker cables
incorrectly wired
The sound is not precise, Speakers are connected out of Ensure method of conn-
lacking bass and stereo phase, i.e. connections to one- ection is the same for left
image speaker (+ and -) are reversed and right speakers

A308 CR Power Instructions for Use Page 7of 7
SPECIFICATIONS :
Output voltage, RMS 45 Volts 20Hz to 20kHz
peak 127 Volts
Power output, single or both channels driven 250 Watts per channel into 8 Ohms (24dBW)
450 Watts per channel into 4 Ohms
Peak-to-peak output current 72 Amps
Damping factor 180
Output devices per channel 6
Total Harmonic Distortion + noise 0.003% at 1kHz up to 90% power, into 4 or 8 Ohms
< 0.007% 10Hz to 40kHz at 12.5 Watts into 8 Ohms
Intermodulation distortion 0.002% at 12.5 Watts into 8 Ohms
Frequency response 20Hz to 20kHz ±0dB
10Hz to 100kHz +0 / -1.5dB
Channel separation > 100dB 20Hz to 20kHz
Audio gain 30dB (31.5 times) nominal
Input impedance 31K Ohm
Input sensitivity for full power output into 8 Ohms 1.42 Volts
Signal / noise ratio, reference full power output > 124dB “A”- weighted
Inputs “A” : 1 pair RCA connectors, selectable from the front panel
“B” : 1 pair RCA connectors, selectable from the front panel
Outputs 2 amplifier channels via 2 pairs of speaker binding posts
per channel,
1 pair RCA loop output sockets
Power requirements 100 / 115 / 230V AC, 50 / 60Hz (factory preset)
1000 Watts maximum into 8 Ohms load
70 Watts idle
Dimensions 440 mm, 17.3 inches wide
143 mm, 5.6 inches high including feet
394 mm, 15.5 inches deep including terminals
Weight 23.5 kg, 51.7 lbs unit only, unboxed
26 kg, 57.2 lbs in shipping carton
Standard accessories IEC type mains lead
Issue 3: March 2003
Musical Fidelity reserves the right to make improvements which may result in specification or feature changes without notice.
A308 CR
Dual Mono Power Amplifier