Power Modules Belles 350A Reference User manual

ReferencePower Amplifier
Instruction Manual

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Important Safety Instructions
For your safety please read the following instructions carefully before
installing and connecting this unit to the mains supply. We advise you to
follow all instructions, adhere to all warnings and keep these instructions
for future reference.
WARNING – to reduce the risk of fire or electric shock:
•Do not remove the cover from the unit.
•Do not expose the unit to rain or moisture.
•The unit must not be used near water or exposed to dripping or
splashing water or other liquids.
•Do not place vases or other objects filled with water on the unit. In
the event of any spillage of liquid onto the unit switch off
immediately, disconnect from the mains supply and contact your
dealer for advice.
•Do not use any cleaning fluids on the unit. Do not spray aerosols at
or near the equipment. To clean the unit use a dry, lint-free cloth.
•Do not place naked flame sources, such as lighted candles, on the
unit.
•Ensure that small objects do not fall through any ventilation grills.
If this occurs switch off immediately, disconnect from the mains
supply and contact your dealer for advice.
Safety Precautions
Check that the rear of the unit indicates the correct mains supply voltage
and frequency. If your mains supply voltage or frequency is different
please consult your dealer. The unit is designed to operate only on the
supply voltage and type that is indicated on the rear panel. Connecting
the unit to other power sources may result in damage.
The unit is of Class 1 construction and must be connected to a mains
socket outlet with a protective earth connection. The unit must not be
used unless correctly earthed and must be switched off when not in use.
The power supply cord is intended to serve as the disconnect device, the
mains socket-outlet shall be installed near the equipment and shall be
easily accessible. If you do not intend to use the unit for a long period of
time, unplug it from the mains socket. Unplug the unit during lightning
storms.
Terminals marked with the following symbol are hazardous live and
external wiring connected to these terminals requires installation by a
competent person or the use of ready-made leads or cords.

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The unit must be installed on a sturdy level surface and ensure there is
adequate ventilation (at least 10cm all round). Do not put objects on top
of the unit. Do not situate the unit on a rug or other soft surface or
obstruct any air inlets or outlets. Do not install the unit near any heat
sources such as radiators, stoves or other apparatus that produce heat.
Do not locate the unit in an enclosed area such as a bookcase or in a
cabinet with insufficient ventilation. Do not stack multiple units on top of
each other.
The unit is not user serviceable and no attempts should be made to repair
or disassemble it in the event of a fault. Servicing is required if the unit
becomes damaged in any way, such as the power supply cord or plug
being damaged, liquid been spilt or objects have fallen into it, if the unit
has been exposed to rain or moisture, has been dropped or does not
operate normally.
This product complies with the European Low Voltage
(2006/95/EC) and Electromagnetic Compatibility
(2004/108/EC) Directives when installed and used in
accordance with this instruction manual.
The crossed-out wheeled bin is the European Union symbol
for indicating separate collection for electrical and electronic
equipment. This product contains electrical and electronic
equipment that should be reused, recycled or recovered and
so should not be disposed of with unsorted regular waste.
Please return the unit or contact your authorised dealer from
where the product was purchased for more information.
Plug Fitting Instructions (U.K.)
The power cord supplied with this product is factory fitted with a 13amp
mains plug fitted with a 4.0 amp slo-blo fuse. If it is necessary to change
the fuse it is important that a 4.0 amp slo-blo replacement fuse is used. If
the plug needs to be changed because it is not suitable for your socket, or
becomes damaged, it should be cut off and an appropriate plug fitted
following the wiring instructions below. The unused plug should be
disposed of safely as insertion into a 13amp socket is likely to cause an
electrical hazard. Should it be necessary to fit a 3 pin BS mains plug to
the power cord the wires should be connected as detailed below. The
colours of the wires in the mains lead of this product may not correspond
with the coloured markings identifying the terminals in your plug. Connect
them as follows:
The wire which is coloured BLUE must be connected to the terminal which
is marked with the letter ‘N’ or coloured BLACK.

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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 GREEN/YELLOW must be connected to the
terminal which is marked with the letter ‘E’ or coloured GREEN.
If a 13amp (BS1363) plug is used, a 4.0 amp slo-blo fuse must be fitted
or if any other type of plug is used a 4.0 amp slo-blo or 4.0 amp slo-blo
fuse must be fitted, either in the plug or adapter or on the distribution
board.

Introduction
Congratulations. You have purchased an amplifier that is the culmination of 20 years of
amplifier research experience. David Belles has designed the Belles 350A Reference to
exceed in performance any amplifier in its class.
The Belles 350A Reference had been designed to be a reliable part of your precision
sound system, assuming it is handled and installed properly. We have provided these oper-
ating instructions for you, which, if followed, will insure you years of listening enjoyment.
The Belles 350A Reference is designed for systems using either 2, 4 or 8 ohm speakers.
WARNING: DO NOT move the speaker leads or interconnect cables until the amplifier has
been powered off at least 30 seconds. Failure to follow this waring will cause the line fuse
to blow.
Care
The most important thing you can do for your amplifier is clean it properly. There may be
occasions when dust or dirt my build up on your unit. Polishes, cleaners, solvent or any
ammonia based cleaners will damage the aluminum anodize finish of your unit. Use a
clean cloth and wipe the dirt from the unit. Use greater pressure to clean more persistent
dirt. With proper care, the appearance of the Belles 350A Reference will be preserved for
years.
Unpacking the Unit
When you receive your unit, carefully inspect the carton for any damage. Any obvious
dents or scuff marks should alert you to the possibility of damage to the contents. If any
external damage to the carton is found, note the location in relation to the orientation of the
amplifier as it is removed from the carton.
Open the top flaps of the carton and carefully remove the unit, lifting it straight out of the
carton. Inspect the unit for damage, paying particular attention to those areas that corre-
spond to any damaged areas on the outer carton.
If your unit was damaged (1) Contact your dealer if the unit wa purchased locally. (2)
Contact your common carrier (eg- UPS) if your unit was shipped to you. Do not send the
unit back to the shipper until instructed to do so by the carrier. To do so may void any dam-
age claim you may have.
Do not discard your packing materials or cartons. Should it be necessary to return the
unit, it must arrive undamaged. Using the original packing materials will ensure your unit
arrives safely. Sending your unit back in improper packing could lead to the unit being
damaged, with no possibility of a successful claim against the carrier. The unit must be
placed in the original packing bag to avoid marring the unit.
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Installing the 350A Reference
Amplifier placement requires careful planning. It must be physically located a safe distance
away from the other components in the system that radiate strong signals. Ideally it will be
located near the speakers— preferably between them. This will minimize the effects of
speaker wires interacting with the amplifier. In any case, the amplifier should be located as
close to the speakers as practically feasible.
The Belles 350A Reference is equipped with raised rubber feet for the following reasons:
(a) To raise the unit up sufficiently so that continuous ventilation can be maintained, (b) To
eliminate acoustic feedback, and (c) To provide a measure of protection against scratching
any surface on which the unit is placed.
-DO NOT REMOVE THE FEET OR PLACE THE UNIT ON DEEP PILE CARPET.
-DO NOT PLACE THE UNIT ON TOP OF ANY OTHER PIECE OF ELECTRONIC GEAR.
-DO NOT PLACE ANY OTHER ELECTRONIC GEAR ON TOP OF THE AMPLIFIER.
Ensure that proper ventilation is maintained at all times. Excessive heat buildup can
seriously damage this unit.
Connecting the Belles 350A Reference in a Two Channel System
IMPORTANT: In order to eliminate potential damage to other components, always unplug
the amplifier(s) before unplugging or plugging in the preamplifier or sound processor power
cord or the interconnect cables running from the preamplifier/sound processor to the ampli-
fier.
When plugging in or unplugging interconnect cables running from the source to the pream-
plifier or sound processor, always make sure that the preamplifier or sound processor vol-
ume control is set at zero.
1. Before doing anything, be sure that the power switch on the amplifier’s front panel is in
the off position. Please do not turn the amplifier on until directed to do so.
2. Locate the A.C. power supply cord. Do not connect the power cord to the A.C. power
supply yet.
3. If you are using the amplifier in unbalanced mode, connect the interconnect cables from
the preamplifier or sound processor to the appropriate left and right gold input connectors
on the rear panel.
NOTE: If you are using balanced interconnect cables, read the next section on how to
enable the balanced connectors for operation. Once you have performed the steps in that
section, return to this section and resume at step 4.
4. Connect the cables from your speakers to the appropriate left and right “Audio Out” out-
put connectors. Be sure that the speaker leads plus and minus are not shorting-out at
either the amplifier binding posts or the speakers binding posts, and that the leads are not
connected in reverse polarity.
5. Double check the cable connections for both the interconnects and the speaker cable to
be sure that they are properly connected, and that the connections are tight.
6. Be sure that the preamplifier or sound processor volume control is set at zero. Plug the
amplifier’s power cord into the A.C. power source. Turn the power on by depressing the
amplifier’s power switch. The front panel light should be illuminated.
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Connecting the Belles 350A Reference Monoblock
IMPORTANT: In order to eliminate potential damage to other components, always unplug
the amplifier(s) before unplugging or plugging in the preamplifier or sound processor
power cord or the interconnect cables running from the preamplifier to the amplifier.
When plugging in or unplugging interconnect cables running from the source to the pream-
plifier or sound processor, always make sure that the preamplifier/sound processor volume
control is set at zero.
1. Before doing anything, be sure that the power switch on the amplifier’s front panel is in
the off position. Please do not turn the amplifier on until directed to do so.
2. Assign one monoblock to the left channel, and one to the right channel.
3. Connect the balanced cable to the left monoblock balanced mono input. Repeat the
same for the right monoblock.
4. Connect the left speaker cable positive (red wire) terminal to the left monoblock right red
speaker binding post.
5. Connect the left speaker cable negative (black wire) terminal to the left monoblock left
red speaker binding post. There should be no connections to either black binding post.
6. Connect the right speaker cable positive (red wire) terminal to the right monoblock right
red speaker binding post.
7. Connect the right speaker cable negative (black wire) terminal to the right monoblock
left red speaker binding post. There should be no connections to either black binding post.
8. Connect the power cords to each amplifier.
9. Power on the system using the following order: sources (such as CD player, tuners,
etc), preamplifer, monoblocks. Use the reverse order to power off the system.
NOTE: The balanced mono input connector is wired as follows:
1. The positive phase signal connets to pin 2 of the XLR connector and drives the amplifier
right channel.
2. The negative phase signal connets to pin 3 of the XLR connector and drives the amplifi-
er left channel.
3. The signal common is pin 1of the XLR connector.
Preparation and Checkout
Like any high performance, audiophile quality component, the Belles 350A Reference
requires about 250 hours of circuit forming (burn-in) time before a realistic evaluation of its
capabilities can take place. We recommend that you run the white noise from an FM tuner
into your system, with the speakers connected, at low volume, as one method of ‘forming’
the components and signal pathways of your amplifier. An alternative method involves
playing music from a CD source, with the CD player set on ‘repeat.’
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Specifications
The specifications for the Belles 350A Reference power amplifier are as follows:
Stereo single channel power . . . . . . . . . . .20 to 20,000 Hz (250 watts per channel into
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8 ohms, 500 watts per channel into 4 ohms)
Monoblock power . . . . . . . . . . . . . . . . . . . .20 to 20,000 Hz (1000 watts per channel into
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 ohms)
Distortion . . . . . . . . . . . . . . . . . . . . . . . . . .THD and IM less than 0.1% at rated power
Damping Factor . . . . . . . . . . . . . . . . . . . . .over 2000
Peak Current . . . . . . . . . . . . . . . . . . . . . . .64 amperes
Stereo Inputs . . . . . . . . . . . . . . . . . . . . . . .Unbalanced stereo only
Monoblock Inputs . . . . . . . . . . . . . . . . . . . .Balanced only
Input Sensitivity . . . . . . . . . . . . . . . . . . . . .1.98 for rated power
Input Impedance . . . . . . . . . . . . . . . . . . . .50,000 ohms
Hum & Noise . . . . . . . . . . . . . . . . . . . . . . .over 100 dB
Crosstalk . . . . . . . . . . . . . . . . . . . . . . . . . .over 60 dB
Frequency Response . . . . . . . . . . . . . . . . .0.2 to 100,000 Hz
Dimensions . . . . . . . . . . . . . . . . . . . . . . . .17" W x 5.25" H x 16.5" D
Shipping Weight . . . . . . . . . . . . . . . . . . . . .65 pounds
Power Rating . . . . . . . . . . . . . . . . . . . . . . .120 VAC 10.0 A Fuse (240 VAC available on
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . request)
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Limited Warranty
Power Modules Inc., herein referred to as the “manufacturer”, guarantees
this product to be free from defect in both material and workmanship, and agrees to
remedy any such defect or replace any defective component at no charge for a
period of five years from the date of sale to the first end user. This warranty is void
if the product has been found to be subjected to misuse, abuse, lightning strike,
unauthorized service, damaged in transit, or has been altered or repaired in such a
way so as to detract from its performance, reliability, or its safe operation.
Should such a defect be discovered and it falls within the terms of this guar-
antee, the manufacturer will correct the defect in workmanship and/or replace any
defective component with a new one of similar capability and value. This warranty
does not apply to the cabinet or appearance items such as the faceplate, control
knobs, or meter lenses, nor does it cover any expenses incurred in shipping the
unit to the appropriate service depot.
The foregoing is in lieu of any other warranties expressed, implied, or statu-
tory and the manufacturer neither assumes nor authorizes any person to assume
for it any other obligation or liability in connection with the sale of this product. This
warranty is not transferable except by written authorization from the manufacturer.
In order to qualify under the terms of the above warranty, all items must be
returned to the appropriate factory service depot with all shipping charges prepaid.
In lieu of having previously registered the purchase of the unit by completing and
returning the attached Purchase Registration Card, the unit must be accompanied
by proof of purchase (bill of sale) from an authorized Power Modules dealer.
Power Modules Inc.
Please Note: Defective units must be returned to the selling dealer or to Power
Modules at their service depot within the country of sale.
The shipping address is: Power Modules Inc. 479 East St. Pittsford, N.Y. 14534
Phone Number: [phone]
Warning
TO PREVENT SHOCK OR HAZARD, DO NOT EXPOSE THIS APPLIANCE TO
RAIN OR MOISTURE. TO REDUCE THE RISK OF ELECTRICAL SHOCK, DO
NOT REMOVE COVER OR FACEPLATE. NO USER SERVICEABLE PARTS
INSIDE. REFER SERVICING TO QUALIFIED SERVICE PERSONNEL.
Model No. _________________________ Ser No.______________________
Purchased From _____________________________ On ___________________
(Name of Dealer) (Date)