Jas Audio Bravo 3.1 User manual

JAS Bravo 3.1
Vacuum Tube Class A
Integrated / Power Monoblocks Amplifier
OWNER’S MANUAL
NOTE: Before installing your new Bravo 3.1 audio amplifiers, please read
this manual carefully. It will inform you of the product specifications and also
proper installation and operation procedures.
For additional requests
If you have any additional questions regarding the
installation or operation of our products, you are welcome to
contact us directly via email: “[e-mail]“, and please
check frequently our JAS Audio official website: “ http://www.jas-
audio.com “.
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JAS AUDIO HIGH FIDELITY
Class A Monoblocks Amplifier System
Welcome to JAS Audio Family! This JAS Bravo 3.1 Integrated/Power Monoblocks
Amplifier is designed and manufactured to the highest quality standards. The
design exemplifies performance, elegance, and simplicity. You will find this tube
amplifier visually pleasing and easy to use without going through pages of
instructions.
IMPORTANT: before operating the unit, make sure you are familiar with the
safety measures documented below.
Bravo 3.1 OWNER’S MANUAL
Introduction
Thank you for purchasing the JAS Audio Bravo 3.1 Integrated / Power Monoblocks
Amplifier. This pair of monoblocks is of dual mono design fitted with 3 tube rectifiers, 3
chokes and a direct heated 3-pole 2A3 vacuum tube connected to the transformer for
driving the 805 vacuum tube so as to attain a power output of 32W per channel. This
single-ended class A integrated/power amplifier is truly amazing in sound reproduction
that presents a character of clarity, transparency, and dynamic sound reverberating in a
huge sound stage for hours of music enjoyment by audiophiles.
Preliminary
The front panel of Bravo 3.1 features an analog volume control knob and a power switch.
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They are of uniformity with the panel in color and material in production. Lined on both
sides of the front transformer cage with wooden cover are two rows of tubes, including one
row of rectifiers and another row of tubes on the other side for signal amplification, drive
stage and output stage. The
805 output tube is fitted on the antique “holdover–socket”, a
design that requires a gentle push downward and an action to turn in releasing the tube.
All
the transformers are housed in two separate cages mounted on the chassis as a T-joint.
Apart from the IEC power inlet and the taps for 4Ωand 8Ωimpedance matching with
speakers, there is also a by-pass switch located at the back of the chassis. The
operating
mode is selectable by switching the by-pass switch left or right. Please make sure
that switches on both chasses are set to the same side so as to work on the same operating
mode before powering up the amplifier.
This pair of monoblocks is recommended to match with Bravo 1.1 vacuum tube pre-
amplifier of the same series to build a high-end set up for optimal performance.
Power Switch Volume Control Knob
___________________________________________________________
It is important to be careful with tube installation. Please do not force anything, easy
does it! This precaution is mentioned to help you obtain pleasing results and avoid
damage! If you have any trouble replacing or changing tubes, please don’t hesitate to
call your dealer!
___________________________________________________________
Tube Replacement
Caution: Make sure the amplifier has been unplugged for 30 minutes from the AC mains
before replacing the tubes, to avoid any risk of shock or discomfort from high
temperature. Although tube life span varies depending on the nature and degree of use,
under normal home use, the 805 output tube and the 2A3 driver tube should last years in
the Bravo 3.1. The 6J4P input tubes and the 5Z3P rectifier tubes should last longer
though.
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Cautionary Terms
When the following cautionary terms are used in this manual, these
definitions apply:
Electrical hazard! Misuse or failure to follow instructions properly
may result in personal injury or death!
CAUTION: No risk of personal injury; however, misuse or failure
to follow instructions may result in damage to equipment.
NOTE: No risk of personal injury or equipment damage; however,
misuse or failure to follow instructions may prevent proper performance
NOTE: Any current production or New Old
Stock (NOS) types of 805, 2 A3, 6J4P and 5Z3P
tubes will work fine in the JAS Bravo 3.1 Tube
Monoblocks Amplifier. The voltages should work
fine with all compatible types.
IMPORTANT: never wiggle the 805 tube
while pulling it out from the socket. The owner
should hold down the tube, and turn it
anticlockwise until it releases gently. Again,
please do not force anything, easy does it!
On the same principle, do not turn the 805 tube too tightly when replacing it in the socket.
Moreover, the 805 tube has a unique ceramic plate cap, which must remain connected to
the contact on top of the 805 tube all the time except when repairs are needed (see
pictures below). Caution: do not leave the ceramic plate cap in the air, unconnected!
When powering ON, make sure the cap is connected properly.
Caution:
Do not leave the Ceramic –
Plate-Cap in air before
Power ON!
NOTE: LOOK CAREFULLY at the tube pins and socket and make sure that you
insert the pins correctly. In most cases, replacing 2A3, 6J4P and 5Z3P tubes presents
no problem. The tube can be made to release by pulling it out gently (sometimes with
a little back and forth wiggling). However, improper handling may possibly force the
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tube pins into the socket in the wrong way! If you install the tube wrongly, you will damage
the amplifier and the tube as well. This kind of damage will not be covered by the
manufacturer’s warranty. If you have any doubt about this, please call your local dealer for
assistance.
Unpacking before installation
All shipping containers have been specially designed to protect their contents and special
care has been taken to prevent damage under normal shipping conditions. Mishandling
should be evident upon inspection of the shipping container. If shipping damage is found
after visual inspection, take care not to destroy the evidence. If necessary, document the
damage with photographs and contact the carrier immediately.
On receipt of the product, unpack and examine it closely for signs of shipping damage. It
is recommended to save all original packing cartons and crates to protect your amplifier
from damage should you wish to store it or ship it for after-sales service.
Installation and Set Up
8Ω 4Ω 0
Three-way taps provide output to the speaker
system (4Ωor 8Ωconnections).
Power Requirements: The Bravo 3.1 is
designed to operate from the AC mains (house
current). A standard IEC AC power inlet with a
built-in fuse is provided on the back panel of
each chassis. The Bravo 3.1 is factory pre-set
according to current supply of the region for
distribution.
Caution: Turn the power switch on at Power On position for both channels, the output
tubes will light up.
Power-On Operation
Your new amplifier is ready for operation after the
speaker cables, interconnect cables and tubes have been
properly installed. Before powering up the Bravo 3.1,
please make sure to choose the operating mode (either
Integrated or By-pass) by using the selector switch
located between the RCA input connectors on the back
panel. Set the switch to left for by-pass mode, or to the
right for integrated mode. Only change the By-pass switch
setting when the amplifier is powered OFF. We
recommended extreme high quality silver cables or
speaker, interconnect, and power connections. Please ask
your local dealer for additional information.
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Features
ƒ Single-end Pure Class-A circuitry offers harmonic purity and sonic transparency.
ƒ Monoblock configuration reduces crosstalk noise (in which a signal disrupts another
signal in an adjacent circuit; Signal mix partially and confuse one another).
ƒ Selected and matched 2A3, 805 and 6J4P tubes
ƒ Can be switched between Integrated amplifying mode and Power amplifying mode
ƒ Separate wide-band audio power and output transformers, and the application of 3
chokes to regulate current flow at different levels of frequency response.
ƒ Additional internal damping material for added control of mechanical resonance
ƒ 4 and 8-ohm output impedance taps for optimum speaker impedance matching
ƒ Bravo series tube amplifiers are built with point-to-point master handcraft soldering
ƒ Circuit structure inside the chassis is of a combination of different circuit boards
that serve different functions. All separate boards are integral parts of the entire
circuit, and are connected with internal wiring welded with uniform and firm
welding points.
ƒ Factory pre-set voltage operations with fuse protects amplifier circuit in case of
current overload.
Running-In Period
The tubes, capacitors and the output transformers take approximately 100 hours of music playing to
fully settle in for peak performance.
Small imperfections in the tube surfaces will ‘boil off’
during the break in period as well.
The amplifier will sound good right out of the box but it will
improve as break-in occurs. After the first couple of hours you will notice increased depth and tighter
bass. This break-in phenomenon is true of
most high performance audio amplifiers .
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Aftercare
The chassis may be cleaned with a soft towel cleaner. The frequency of cleaning will be governed
by the cleanliness of the operating environment. Spray the cleaner on the towel, not on the
amplifier! Avoid abrasive cleaners! Feather dusters are
good for cleaning the amplifier.
Limited Warranty
This product has been designed and manufactured to the highest quality and standards. However,
if something does go wrong with this product, JAS Audio and its national distributors
warrant,
free of charge,
labor (exclusion may apply) and replacement parts in any country served by an
official JAS Audio distributor.
This limited warranty is valid for a period of 3 years from the date of purchase of an
amplifier or six months for vacuum tubes.
Terms and Conditions
1. The warranty is limited to the repair of the equipment. Neither transportation, nor any other
costs, nor any risk involved in removal, transportation and installation of
products is
covered by this warranty.
2. This warranty will not be applicable other than in case of defects in materials and/ or
workmanship at the time of purchase and will not
be applicable:
a. for damages caused by incorrect installation, connection or packing;
b. for damages caused by any use than described in the user manual, or by
negligence,
or by modifications, or by use of parts that are not
made or authorized by JAS Audio;
c. for damages caused by faulty or unsuitable auxiliary equipments;
d. for damages caused by accident, lighting, water, fire heat, war,
public disturbances or any other cause beyond the reasonable control of JAS Audio
and its appointed distributors;
e. for products whose serial number has been altered, deleted, removed or made illegible;
f. if repairs or modifications have been performed by an unauthorized person.
3. This guarantee complements any national/regional law obligations of dealers
or national distributors and does not affect your statutory rights as a customer.
How to claim repairs under warranty
Should service be required, please follow the procedure listed below:
1. If the equipment is being used in the country of purchase, you should contact
the JAS Audio Authorized dealer from whom the equipment was purchased.
2. If the equipment is being used outside the country of purchase, you should
contact JAS Audio National distributor in the country of
residence who will advise where
the equipment can be serviced.
TO VALIDATE YOUR WARRANTY, YOU WILL NEED THE ORIGINAL
SALES INVOICE OR OTHER PROOF OF
OWNERSHIP AND DATE OF
PURCHASE.
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Technical Specifications
Product Model: JAS Bravo 3.1
Description: Class A Triode Monaural Amplifiers
Technical Features: Single-Ended Class-A Triode Circuit Topology
with Integrated / By-pass function
Power Requirement: AC 115 @ 50-60Hz set
Power Output: 32W X 2
Input Sensitivity: 0.35V for 30W
Input impedance: 47 K
Ω
Frequency Response: 16 Hz – 30 KHz (-3dB)
Total Harmonic Distortion: ≤1% (8W)
S/Nratio: 80dB
Tube Complement: 805 x 2, 5Z3P x 6, 2A3 X 2, 6J4P X 2
Chassis Dimensions: 330 (W) x 240 (H) x 450 (D) (mm)
Packing Box Sizes: 560 (W) x 430 (H) x 380 (D) (mm)
Net Weight: 23 kg /pc x 2 units
Gross/Shipping Weight: 24.5 kg /pc x 2 units
JAS AUDIO is constantly striving new design improvements, we reserve the right
to change or modify product specifications without prior notice or obligation.
Note: The twin units of the Bravo 3.1 are packed individually and sent as a pair to
our dealers. All Bravo 3.1 amplifiers have their own serial numbers (S/N xxxxxA/B),
marked on the back of the chassis, and are written on the exterior of the packing
box.
Happy Listening to all music lovers!
Best Regards,
Set your mind free!
Version 1.0 and Copyright © Jan 2008 JAS AUDIO
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