1.
USER MANUAL
PROJECT TWELVE
MONO POWER AMPLIFIER
SPHINX Project Twelve
1. UNPACKING.......................................................................................................................................3
2. SPHINX WARRANTY CARD ..............................................................................................................3
3. THE POWER AMP AT A GLANCE.....................................................................................................4
Front panel...................................................................................................................................................4
Rear panel ...................................................................................................................................................5
4. INSTALLATION AND CONNECTIONS..............................................................................................6
Installation....................................................................................................................................................6
Connections in general................................................................................................................................6
Connecting loudspeakers............................................................................................................................6
Connecting the input....................................................................................................................................6
Connecting the optical cables......................................................................................................................6
Connecting the mains cable ........................................................................................................................7
5. OPERATION........................................................................................................................................8
Power On.....................................................................................................................................................8
Power off...................................................................................................................................................... 8
Warnings .....................................................................................................................................................8
Encountering problems................................................................................................................................8
6. CARE AND MAINTENANCE.............................................................................................................10
7. TECHNICAL SPECIFICATIONS.......................................................................................................10
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SPHINX Project Twelve
Congratulations on your purchase of the Sphinx
Project Twelve!
You are now part of an ever-increasing group of
quality-conscious audiophiles using Sphinx
products.
We are very proud of the tradition connected with
the SPHINX name, especially concerning audio
quality perfection.
This manual will help you to gain a maximum
amount of pleasure and quality from your new
Sphinx Project Twelve.
The design is based on the long experience of the
Sphinx design team with ultra-wide bandwidth
power FET's.
These have an unique and extremely wide power
bandwidth exceeding 1.5 MHz, a very high slew
rate of over 100 V/µs and an unequalled perfect
phase linearity over the complete frequency
bandwidth.
The extremely low output impedance results in a
damping factor of over 600!
Together with the very 'heavy' power supply and its
large energy buffer of 26,920 µF, this results in an
effortless sound with a very large dynamic range
and an unsurpassed transient response.
Much attention has also been paid to the physical
layout, the positioning of components and the
internal grounding. This results in an equivalent
input noise value of <1 µV (<-120 dBV): remarkable
for a pre-amp, but really astounding for a big power
amp with two transformers.
All of this means that the Project Twelve can work
with all kind of loads from every loudspeaker: even
the most difficult ones like electrostatic and
magnetostatic.
1. UNPACKING
Before leaving the factory every Project Twelve is
subjected to stringent and extensive technical and
exterior quality inspection.
This ensures you will enjoy many years of high
quality audio from a perfect-looking product.
Attention: The power amp weighs over 6.5 kg
(14.33Lb). Never lift it out of the box without
someone helping you.
After unpacking your Project Twelve we therefore
recommend you carefully check it for any transport
damage.
In case of damage: please contact your Sphinx
dealer immediately and retain all packing materials
for possible proof of damage and possible claims.
Even if the component is in perfect condition you
should still keep the packing materials. If you need
to transport your Project Twelve at a later time it will
be best protected by the original packing materials.
2. SPHINX WARRANTY CARD
Please take this opportunity to fill out the enclosed
warranty card now!
Follow the instructions on the card or consult your
dealer.
Please send the card as soon as possible to the
return address (within 14 days after purchase).
To obtain the maximum quality from this power amp
it is necessary to use it with top quality audio
components preferably with other Sphinx
components.
Please read this manual carefully before you
install or use the Project Twelve. It is
important to familiarise yourself with the
special functions, operation and possibilities
of the Sphinx Project Twelve.
Your local dealer will be able to answer any
questions concerning other Sphinx audio
components.
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3. THE POWER AMP AT A GLANCE
Front panel
SPHINX Project Twelve
1. LED: Indicates the selected function:
stand-by red
on green
protection blinking red.
2. STANDBY: To switch the component on and
off.
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Rear panel
SPHINX Project Twelve
1. BALANCED/UNBALANCED: With this switch
you may select the input (4.) to balanced
(switch IN) or unbalanced.
2. CONTROL IN: To connect the optical cable
from another Sphinx component like a pre-amp.
CONTROL OUT: To connect the optical cable
that goes to another Sphinx component.
3. XLR input: To connect the XLR cable from the
pre-amp output.
4. POWER: This is the mains master switch.
MAINS: To connect the power amp to a mains
outlet (230 - 240 VAC).
5. OUTPUT: To connect the cable from the
loudspeaker:
red +
white -
6. Cinch: To connect the cinch cable from the preamp output.
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SPHINX Project Twelve
4. INSTALLATION AND CONNECTIONS
Installation
Make sure you place the Project Twelve on a stable
and sturdy support, it weighs over 6.5 kg.
Never 'stack' two power amps on top of each other.
The Project Twelve will become warm, so correct
placement is critical. Do not position it on top of or
close to other heat-radiating equipment (such as
other power amps) or in direct sunlight.
Please ensure unrestricted ventilation around
the component.
If you need to use the amp in a closed cabinet or on
a bookshelf, you should provide unrestricted
ventilation around the component..
We recommend positioning each Project Twelve as
close as possible to each loudspeaker.
To prevent any possible interference keep power
supply cables away from all audio cables.
If all these conditions are met, the Project Twelve
will perform to the extremely high standards it is
designed for.
Connections in general
Before you start connecting equipment it is always
wise to check whether all the mains cables of all
components are disconnected from the mains
outlets!
This will prevent any damage to the loudspeakers
and amplifiers caused by incorrect wiring or
settings.
Always use loudspeaker and audio cables and
connectors of the highest quality.
Siltech SPO cable is used throughout internally and
we recommend using this same cable for all
external connections.
If you have the choice between longer loudspeaker
cables or longer audio cables, choose the latter
(cables between pre-amp and power amp will cause
the least signal quality loss).
Connecting loudspeakers
We recommend using a double pair of cables, if this
is possible with the loudspeaker (one pair for the
highs and another for the lows).
In most cases you will hear a substantial
improvement in the sound quality (but be careful to
prevent shorted connections).
Your dealer can recommend the best cables and
connection methods.
Connect the red OUTPUT terminal (6.) to the red or
'+' terminal of the loudspeaker.
Connect the black OUTPUT terminal (6.) to the
black or '—' terminal of the right loudspeaker.
When using unterminated cables please check
carefully that there are no 'loose ends' to cause a
short between the '+' and the '—' of the terminals on
amp and loudspeaker!
Connecting the input
The balanced XLR input (5.) can be used to
connect any balanced line level signal (such as
from a pre-amp).
The balanced signal cable is the best and preferred
connection method.
Be sure to connect it properly though.
The unbalanced cinch input (8.) can be used to
connect any unbalanced line level signal (such as
from a pre-amp).
Be sure to connect it properly though.
When making the connections please refer to the
descriptions for parts 2. to 8. on page 5.
Connecting the optical cables
The Project Twelve has an optical jack connector
for CONTROL IN en OUT (3.).
When the CONTROL IN of the Project Twelve is
connected to the CONTROL OUT of another Sphinx
component, you don't have to switch the Project
Twelve with POWER switch (5.). The power amp
will automatically select Stand-by mode as soon as
the other component is set to stand-by.
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SPHINX Project Twelve
If you connect the CONTROL OUT of the Project
Twelve with the CONTROL IN of another Sphinx
component (usually another power amp), this will
also automatically be selected to stand-by as soon
as the Project Twelve is set to stand-by.
In 'stand-by' mode the bias current of the power
amp is set to a lower level, which drastically
decreases the temperature and power
consumption. Additionally it significantly increases
the life span of the component.
The power amp also warms up more quickly so you
will be able to enjoy maximum performance without
significant delay.
Ensure proper connection of the optical cables
(from CONTROL OUT to CONTROL IN), otherwise
the LED on the front panel may remain green even
though the stand-by mode is activated.
If the Project Twelve is placed in strong direct
sunlight and you do not use an optical connection
the stand-by mode may self-activate. In that case
you should place the supplied dummy connector in
the CONTROL IN jack (but only if this is not being
used).
We strongly recommend against placing the
component in direct sunlight.
Connecting the mains cable
Before you connect the cable please check
whether the mains voltage indicated on the
manufacturer's label on the rear panel is the
same as your local mains voltage.
If not: please contact your dealer and do not
connect the component to the mains.
Connect the mains cable after you have connected
all other components in the system and have
double-checked all connections.
If you use more than one Project Twelve you should
connect them all to the same mains outlet and
phase.
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SPHINX Project Twelve
5. OPERATION
Connect the mains cable of the Project Twelve to a
mains outlet.
Once you have connected all other components,
you should check again whether the audio and
optical connections to the pre-amp (if any) are
properly made.
Then you may switch the Project Twelve on with the
POWER switch (5.) on the rear panel.
N.B.: If there is no optical cable connected to the
CONTROL IN jack (3.), you should cover this input
with the supplied dummy connector. Or else strong
light (from sun or lamp) may prevent the Project
Twelve from switching-on.
From now on you should switch the power amp on
and off with the STANDBY button of another Sphinx
component connected to the optical CONTROL IN
jack (usually the pre-amp).
This way all circuits will remain at working
temperature and the audio quality will be 100%
within 30 minutes after activating. Additionally it
considerably increases the life span of the
component.
Only if you will not be using the amp for a long
period (e.g. during holidays) should you switch the
amp off with the POWER switch (5.).
In stand-by mode the Project Twelve's power
consumption is around the 5 W mark.
Warnings
1. Never place two amps on top of each other.
2. The component should not be subjected to
moisture or fluids.
3. Do not touch the component and the
loudspeaker outputs especially not with moist
hands: this powerful amp can output voltages
in excess of 36 volt.
4. Before removing the top panel, you should
disconnect the mains cable and wait at least 30
minutes (because the power supply remains at
the maximum voltage for a long time).
Removing the top panel will void your warranty:
the panel should therefore only be removed by
an official Sphinx service engineer!
5. Before disconnecting a loudspeaker or audio
cable, please switch of the component with the
POWER switch (5.)
6. An AC extension cord should never be used
wholly or partly coiled: this poses a severe fire
risk!
The Project Twelve is in stand-by mode and the
LED (1.) shows a red indication.
Power On
Switch the Project Twelve on with the STANDBY
button of the other Sphinx component: the red LED
slowly blinks and after a short period changes to
green.
If you activate the power amp for the first time or
after a long period of non-use with the power 'off',
the amp will be at maximum performance after one
hour. From stand-by mode it takes only around 30
minutes.
Power off
Switch the Project Twelve off (stand-by) with the
STANDBY button of the other Sphinx component.
The LED changes from green to red.
N.B.: If you need to switch the system on again
immediately, you should wait for at least 60 sec
though.
Because switching on the amp within 30 sec will
activate the protection circuits: the red LED will blink
rapidly.
Encountering problems...
The Project Twelve has extensive protection
circuits. These will activate when:
• the temperature exceeds the limit (>70 °C),
• the output has an Offset voltage (>+/-350 mV),
• the output is shorted (current limit) or
• there is no power supply voltage.
If, after power on, the protection circuits detect
something wrong the Project Twelve will
immediately switch to stand-by: the red LED
indication will blink rapidly.
In almost all cases the problem will be with the
loudspeaker cables.
Check them all and solve the problem.
If you can't find the problem or the cause is
definitely not the cables, please contact your Sphinx
dealer.
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SPHINX Project Twelve
Should for some reason the mains fuse be blown,
you should replace it with a new one of exactly the
same type and rating:
5x20 mm
250 VAC / 3.15 A / slow
The fuse (7.) is located at the rear panel next to the
mains connector (8.).
Never use a fuse of a different rating: this could
lead to serious damage and may cause fire!
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6. CARE AND MAINTENANCE
SPHINX Project Twelve
Clean the exterior with a soft, lint-free, anti-static
cloth. Do not use force while wiping the surface.
To remove difficult stains use a few drops of
Do not use polishing or cleaning agents: they
may damage the sensitive acrylic finish of the
Project Twelve.
detergent on a moist cloth, sweep carefully and
wipe dry afterwards.
Do not use aerosol cleaning agents.
Most contain solvents which might react with and
If some scratching occurs, please consult your
damage the acrylic finish.
Sphinx dealer first. He can give you advice about
possible solutions.
7. TECHNICAL SPECIFICATIONS
Bandwidth 0 - 1.5 MHz (+0/-3 dB)
Phase response error <1° (0 - 20,000 Hz)
Gain
Balanced 29.5 dB max. (x 29.9)
Unbalanced 29.5 dB max. (x 29.9)
Minimum Power Output (1 - 20,000 Hz) >151 W into 8 ohm (21.8 dBW), THD<0.01%
Output voltage / current, max. 36 V / 16 A
THD+N (IHF-A) <0.008% (100 W into 8 ohm, 1 - 20,000 Hz)
IMD <0.010% (70 W into 8 ohm)
S/N ratio (IHF-A) >120 Db
0 - 203,000 Hz after RF input filter
>246 W into 4 ohm (23.9 dBW), THD<0.01%
>340 W into 2 ohm (25.3 dBW), THD<0.01%
Slew rate >100 V/µs
Damping factor >600 (1 - 1,000 Hz)
Input XLR balanced / Cinch unbalanced
Level, nominal 1.25 V (1.9 dBV) / 1.25 V (1.9 dBV)
Impedance 600 ohm / 20 kohm
Supply capacitance 26.920 µF total
Power consumption 600 W max. (5 W standby)
Dimensions (h x w x d) 68 x 250 x 340 mm
Weight 6.5 kg / 14.33Lb
This unit conforms to the EMC interference regulations issued by the EU and to the CE standards.
This unit complies with safety regulation VDE 0860 and therefore with international safety regulation IEC 65.
Technical specifications may be changed by SPHINX without prior notice if technical developments make this
necessary.
©1999 Audioscript BV
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