Viola Systems BRAVO REFERENCE AMPLIFIER Owner's Manual
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OWNER’S MANUAL
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BRAVO
JUNE, 200 2
REFERENCE
AMPLIFIER
TABLE OF CONTENTS
Safety Notices…….……………………………………………………….....03
Introduction……..……………………………………………………………….05
Unpacking…….…………………………………………………………………..05
Placement Considerations………………………………………………..06
Special Design Features…………………………………………………..07
Amp Rear Panel…..……………………………………………………………12
Supply Rear Panel………….…………………………………………………13
Mono Operation…………………………………………………………………16
Bridged Operation…………………………………………………………….17
Biamplification…….…………………………………………………………….18
Care and Maintenance………..…………………………………………….18
Troubleshooting………..……………………………………………………….19
Service………...…………………………………………………………………….19
Warranty…………………………………………………………………………….20
Specifications…………..…………………………………………………………22
Dimensions…………….……………………………………………………………23
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SAFETY
WARNING: TO REDUCE THE RISK OF FIRE OR ELECTRIC SHOCK, DO
NOT EXPOSE THIS APPLIANCE TO RAIN OR MOISTURE
CAUTION: TO REDUCE THE RISK OF ELECTRICAL SHOCK, DO NOT
REMOVE COVER. NO USER-SERVICEABLE PARTS INSIDE. REFER
SERVICING TO QUALIFIED PERSONNEL.
The lightning flash with arrowhead symbol, within an equilateral
triangle, is intended to alert the user to the presence of uninsulated
"dangerous voltage" within the product's enclosure that may be of
sufficient magnitude to constitute a risk of electric shock to persons.
The exclamation point within an equilateral triangle is intended to
alert the user to the presence of important operating and maintenance
(servicing) instructions in the l iterature accompanying the appliance.
Please read all instructions and precautions carefully and completely
before operating your power amplifier.
CAUTION: Changes or modifications to this equipment not expressly
approved by the manufacturer will void the user's warranty.
The information contained in the manual is subject to change without
notice. The most current version of this manual will be posted on our
web site at http://www.violalabs.com.
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Important Safety Instructions
Please read all instructions and precautions carefully and completely
before operating your Viola Audio Labs power amplifier.
1. ALWAYS disconnect your entire system from the AC mains
before connecting or disconnecting any cables, or when cleaning
any component.
2. This product must be terminated with a three-conductor AC
mains power cord which includes an earth ground connection. To
prevent shock hazard, all three connections must ALWAYS be
used.
3. AC extension cords are not recommended for use with this
product.
4. NEVER use flammable or combustible chemicals for cleaning
audio components.
5. NEVER operate this product with any covers removed.
6. NEVER wet the inside of this product with any liquid.
7. NEVER pour or spill liquids directly onto this unit.
8. NEVER block air flow through ventilation slots or heatsinks.
9. NEVER bypass any fuse.
10. NEVER replace any fuse with a value or type other than those
specified.
11. NEVER attempt to repair this product. If a problem occurs,
contact your Viola Audio Labs retailer or factory.
12. NEVER expose this product to extremely high or low
temperatures.
13. NEVER operate this product in an explosive atmosphere.
14. ALWAYS keep electrical equipment out of the reach of children.
15. ALWAYS unplug sensitive electronic equipment during lightning
storms.
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INTRODUCTION
Thank you for choosing the Viola Bravo Reference Amplifier. We
have designed and manufactured this exciting product utilizing the
latest techniques and the be st materials available. Our goal is to
provide you with the highest quality listening pleasure available.
UNPACKING
Under no circumstances should you consider unpacking your
amplifier without adequate assistance as both personal injury and
damage to the product is likely unless you follow the procedures listed
below.
Your new VIOLA Bravo Power Amplifier is heavy—the shipping
weight of the Bravo is about 260 pounds (118 kg). We recommend
you use two or three people to unpack these amplifiers safely.
Do not attempt to lift your power amplifier from its packing carton
alone. Never attempt to lift your power amplifier while bending from
the waist. Always stand as straight as possible and use your leg
muscles to lift your amplifier.
After unpacking your Bravo power amplifier, keep all packing
materials for future transport. In the event that you need to ship your
amplifier, only the original, purpose-designed shipping carton is
acceptable. Any other method of shipping this heavy product will
almost certainly result in damage to the amplifier—damage that would
not be covered by the warranty.
Please inspect your amplifier for any obvious damage due to
shipping. If you discover any problems, contact your VIOLA dealer
immediately so an appropriate freight claim can be made.
Although your VIOLA Bravo power amplifier delivers outstanding
performance straight out of the box, you should expect to hear it
continue to improve as it reaches its normal operating temperatures
and its various components "break-in." It has been our experience that
the greatest changes occur within the first 25-50 hours, but that the
amplifier will continue to improve in sound quality for about 300 hours,
after which time it remains quite constant.
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The only exception to this rule is if power is removed from the unit,
allowing it to cool down. This can occur due to: extended power
outages, unplugging the amplifier from the wall during a vacation; or
by leaving the amplifier in sleep mode rather than in standby. In these
cases you should expect a brief warm-up period before the amplifier's
sound quality is at its best. (Fortunately, you will never have to repeat
the full 300 hour break-in period.)
PLACEMENT CONSIDERATIONS
For your protection, revi ew "Important Safety Instructions" above
before you install your amplifier.
Your VIOLA Bravo power amplifier is specifically designed to
accommodate a wide range of installation options. These amplifiers
may be placed on the floor, near the loudspeakers they drive. They
may also be located on shelves provided the shelves are sturdy
enough to bear the weight of the amplifier and have sufficient room for
proper ventilation. The sophisticated ventilation system employed by
the Bravo power amplifier will maintain optimal operating
temperatures in the output stage of the amplifier even when they are
stacked one above another.
However, if you have a choice in your design, locating each amplifier
near its respective loudspeaker is usually best. This approach
minimizes the length of the speaker wires, and necessitates longer
interconnecting cables from the preamplifier to the power amplifier.
The advantage to this strategy lies in the fact that the interconnecting
cables carry low-current signals that are more readily transmitted over
distances with great accuracy than are the necessarily high current
signals required by loudspeakers.
Note that adequate clearance for the AC cord and connecting signal
cables must be left behind your amplifiers. We suggest leaving at least
six inches (15 cm) of free space behind your amplifier so all cables
have sufficient room to bend without crimping or undue strain.
The Bravo power amplifier was designed to use both active and
passive cooling strategies. This highly efficient system features a
forced air cooling system to maintain optimal operating temperatures
under a wide range of conditions. This combination of passive and
active cooling is accomplished by fans running in conjunction with an
efficient system of hea t sinks. Two ultra low-noise fans provide cooling
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from side to side in the amplifier. If you look closely, you will see
crosscuts in the side plates of the amplifier. These cutouts provide the
air intake and exhaust for the forced-air cooling system. The fans’
superior engineering and ball-bearing construction allow them to run
extremely quietly. Most people will never notice them. The only time
you are likely to hear them is when you first turn the volume off after
a prolonged period of extremely high volume listening.
Regardless of where you choose to locate your amplifier, we advise
locating the amplifier near the floor and well away from sensitive lowlevel components. The Bravo power amplifier dissipates approximately
350 watts of energy as heat when on and at idle (no input signal). It is
therefore normal and perfectly safe for them to run somewhat warm.
Mechanical drawings are included in this manual to facilitate special
installations where necessary (see "Dimensions" at the end of this
manual).
SPECIAL DESIGN FEATURES
Congratulations on your purchase of a BRAVO Reference Amplifier
by Viola Audio Labs. While your new amplifier is straightforward in
everyday use, it includes several design features that are responsible
for its outst anding performance. In particular, your new power
amplifier defies the accepted wisdom that it is impossible to design a
large, powerful amplifier that also has all of the finesse of the finest
smaller amplifiers. A few of the technical highlights that make this
possible are given below.
Power Supply
The Bravo power amplifier used as a two box set is a stereo
amplifier with separate power supply. The separate power supply
assures complete freedom from electro -magnetic interference (EMI)
produced by the electromagnetic power supply components, i.e. the
power transformer and inductor (or choke).
The inductor (choke) input filter power supply design was chosen
because it produces far less EMI than conventional capacitor input
systems. The inductor (choke) input filter system greatly reduces the
electrical stress placed on the power supply components. Therefore,
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