Constellation Altair II Owner's Manual
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CAUTION
To reduce risk of electric shock, do not remove any of the preamplifier’s cover plates or screws. There are no
user serviceable parts inside. Contact qualified service personnel.
WARNING
To reduce risk of fire or electric shock, do not expose this preamplifier to moisture, rain, or excessive
humidity.
The lightning flash with arrowhead, 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 electrical shock to persons.
The exclamation point within an equilateral triangle is intended to alert the user to the
presence of important operating maintenance (servicing) instructions in the literature
accompanying the appliance.
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Thank you for purchasing the Constellation Audio Altair II preamplifier. This new revised
version of the original Altair II has been engineered to deliver a superbly user-friendly
experience—and to offer a few subtle performance enhancements as well.
The Altair II employs the same revolutionary circuitry pioneered in our Altair preamp. The
biggest difference is that the user can now control all functions from the front panel. As
with the original, the advanced design necessarily demands a somewhat different setup
process compared with typical stereo preamps. By reading this manual before you operate
the Altair II, you assure that you get maximum performance from your system.
Contents
Page Topic
4 Before you install the Altair II
Unpacking
Power supply setup
Installation notes
In the event of malfunction
6 Source device and amplifier connections
XLR inputs
RCA inputs
XLR outputs
RCA outputs
8 Other connections on the Altair II
Power inputs
DC power
USB / control
RS-232
11 Controls / displays / indicators
Front panel knobs and buttons
13 Remote control
14 Control screens
16 Step-by-step operating procedure
17 Maintenance
17 Troubleshooting
19 For more information
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Before you install the Altair II
Unpacking
Because of its machined aluminum top chassis, the Altair II is heavier than the average preamp. Have an
extra person nearby to help if you need it. You may wish to use gloves to protect your fingers.
NOTE: Prior to plugging in the Altair II, loosen the inner black 5/32" hex shipping set screws near the feet by
four turns.
Power supply setup
The Altair II's separate power supply (bottom component in the picture above) must be connected to the
Altair II main chassis (top component in the picture above) as shown above before you plug the unit into a
wall. Make sure the power switch on the power supply is in the off (O) position.
The supplied cables are spiral-wrapped, gold-plated copper designed for aerospace use, and can handle up to
30 amps. Only these cables should be used between the power supply and the Altair II.
Connect one of the supplied cables to the Right Analog Power socket on the Altair II, then into the Right
Analog Power socket on the power supply as shown above. Repeat with the Left Analog Power and Control
Power connections. At this point you can plug the Altair II power supply into the wall socket. Leave the master
power switch off until you connect your other equipment to the Altair II.
DO NOT remove the power cables while the unit is powered on. If you do happen to accidently pull one of
them out, DO NOT plug it back in. Turn off the power supply using the hard switch on the rear panel, unplug
the unit, then replace the cable. Failure to power down the unit before replacing a power cable can result in
substantial damage to your Altair II.
If you will be using the Constellation Audio Centaur or Hercules amplifiers (or any other high-powered
amplifier), do not plug the Altair II into the same AC socket or into any other outlet connected on that circuit.
Constellation Audio amplifiers draw a great deal of power and could affect the Altair II’s performance if the
amplifier(s) and preamp are plugged into the same electrical circuit or AC outlet.
When you connect or disconnect the AC cord, always grasp it by the plug, not by the cord itself. Pulling the
plug out by the cord can damage the cord, the AC socket, and/or the Altair II.
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Installation notes
The Altair II preamplifier uses passive cooling; there are no internal fans. While the Altair II does not generate
as much heat as an amplifier, it should still be located in an area with adequate ventilation.
There should be at least 6 in/15 cm of clearance between the sides and top of the preamp and the nearest
wall or cabinet. If the Altair II is installed in a cabinet or an equipment closet, ensure the cabinet/closet has
adequate ventilation. Installation in an unventilated cabinet or closet may cause the Altair II to overheat,
significantly reducing its lifespan.
The Altair II requires a room-temperature environment to operation properly. Ambient temperature should be
about 70°F/21°C, plus or minus 10°F/5°C. Never install the Altair II in a place where it may be exposed to
direct sunlight, and do not install it next to a room heater, radiator, air conditioner, etc.
Make sure that the Altair II will not be exposed to moisture. Do not locate it in an area where it might be
spilled on, and do not place it in a humid location (such as an unfinished basement).
The light-dependent resistors used in the Altair II’s volume control need 8 hours of continuous operation to
reach maximum linearity. We recommend leaving the Altair II on all the time to ensure maximum
performance. If the Altair II has not warmed up for 15 to 30 minutes from a cold start, you may notice a
slight left-to-right channel imbalance. This may be corrected temporarily using the balance control.
Installing the Altair II in a place where it will be exposed to direct sunlight or moisture, or where it will not
have adequate ventilation, will void your warranty.
Amplifier
The Altair II preamp is designed to be paired with any high-quality audio amplifier; ideally Constellation's own
Centaur or Hercules amps. Both balanced (XLR) and unbalanced (RCA) connections are available. XLR will
provide the highest quality/lowest noise signals, and should be used when possible.
Before making or changing any connection to the Altair II, first turn off the master power switch on the
preamp’s power supply and turn off the power amplifier.
Source components
The Altair II preamp has eight analog audio inputs, four balanced (XLR) and four unbalanced (RCA), and can
be used with any audio component with line-level analog outputs. As with the outputs mentioned above, an
XLR connection will provide the highest quality signal, and should be used when possible. If you are using a
record turntable, you will need to connect a high-quality phono preamplifier, such as the Constellation Audio
Perseus or Orion, between the turntable and the Altair II preamp.
In the event of malfunction
Do not under any circumstances open the chassis of the Altair II. There are no user-serviceable parts inside.
Opening the chassis can present a shock hazard even if the AC power is disconnected. Any alteration or
modification of the Altair II’s internal parts or circuit will immediately void your warranty. If your Altair II does
not function correctly, refer to the Troubleshooting section at the end of this manual. If you are still unable to
resolve the problem, contact your Constellation Audio dealer. If any liquid is spilled on the preamp, or if any
metal object (such as a staple or a paper clip) is inadvertently forced inside, immediately disconnect the AC
power and contact your Constellation Audio dealer.
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Source device and amplifier connections
1. XLR inputs
On the rear of the Altair II preamp there are eight XLR inputs, four on each side. As you are looking at the rear
panel, the left four XLR inputs are for the right channel, the right four inputs are for the left channel.
Underneath each jack is the corresponding input number. Use of XLR connections is recommended for the
best possible audio quality. To remove an XLR plug, push on the tab above the jack and pull the plug out.
IMPORTANT NOTE: To preserve true dual-mono operation, the Altair II uses a symmetrical circuit layout. This
configuration requires that the Altair II’s back panel connections be laid out a little differently from those on
most preamps. For example, the left-channel connection for Input 1 is at the far right side of the back panel,
and the right-channel connection is at the far left side. Connecting the cables in the usual side-by-side fashion
will result in an incorrect installation and the mixing of sounds from different source devices.
The input numbers from left to right, looking at the back of the Altair II are:
1
, 2
, 3
, 4
——4
, 3
, 2
, 1
right
right
right
right
left
left
left
left
.
2. RCA inputs
These unbalanced inputs are provided as a convenience for use with unbalanced signal sources. Whenever
possible, we recommend using XLR connections instead. Connecting to an unbalanced source is handled in
the same way an XLR balanced source.
The input numbers from left to right, looking at the back of the Altair II are:
5
, 6
, 7
, 8
——8
, 7
, 6
, 5
right
right
right
right
left
left
left
left
.
IMPORTANT NOTE: To preserve true dual-mono operation, the Altair II uses a symmetrical circuit layout. This
configuration requires that the Altair II’s back panel connections be laid out a little differently from those on
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