Constellation Audio Altair II Line Stage User 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 user­friendly 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
RS-232
USB / control
DC power

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.

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.

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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.

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

right

right

right

right

——4

left

, 3

left

, 2

left

, 1

left

.

2. RCA inputs