Classe Audio OMICRON User manual

OMICRON ISSUE 2 DEC ‘98
CLASSÉ AUDIO
OMICRON
POWER AMPLIFIER
OMICRON
OWNER'S MANUAL

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CLASSÉ DESIGN PHILOSOPHY
1. REPEATED LISTENING DESIGN SESSIONS:
Fine tuning of sound by exchanging and mixing of parts (transistors, capacitors, wiring, PCB
boards etc.), and adjusting many specific operating voltages within proper engineering ranges,
producing an overall sonic recipe giving the most natural harmonic realism of music typical of
instruments in a live performance.
2. CIRCUIT DESIGN:
The OMICRON is based on Classé’s whole history of designing and building High End
amplifiers.The OMICRON is an Ultra- High performance amplifier of incredible sonic realism
capable of transmitting to the listener the emotional essence of the music. The OMICRON is
actually two completely separate amplifiers with two massive toroidal transformers totalling 3.6
KVA, each with their own power cords and a huge storage capacity which totals over 80000 uF
per channel. The OMICRON has fourteen high voltage/current Bi-Polar output devices per
channel. Discrete high voltage/current voltage regulation for the pre-driver and input sections.
Also featured are heavily gold plated bars connecting supplies of the output devices. Gold plated
input and output connectors. Oxygen free copper wiring. All signal carrying cables are shielded
and have Litz type configuration. The OMICRON is symmetrical from input to output
3. EXTREME LONG LIFE IN REAL WORLD CONDITIONS:
Choosing the best attainable quality parts and materials combined with the advantages of the two
above-mentioned areas provides Classé owners with years of proven trouble free reliability and
musical enjoyment.

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OMICRON
OWNER'S MANUAL
TABLE OF CONTENTS
UNPACKING & SET-UP.......................................................................... 4
GENERAL CONNECTIONS..................................................................... 5
CONNECTIONS FOR REGULAR AND BALANCED INPUTS…….... 8
PROTECTION CIRCUIT.....................................................….….…….... 10
IR IN AND OUT………………………………………………………… 11
SPECIFICATIONS.................................................…..........….………..... 14

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UNPACKING & SET-UP
Your CLASSÉ OMICRON power amplifier is packed in high density, semi-rigid foam
placed in a special Fiberglas case. To remove the unit, put the fibreglass case with the Classé
lettering right side up. Unlock the four (4) case locking devices by first lifting the tabs, and turning
them fully counter clockwise. Then, pull the tabs; the locking devices will pivot downwards. You
can now remove the large top portion of the case. Take the unit out of the base of the case and
remove the plastic bag and inspect the unit for any concealed damage. Apart from the owner's
manual, please ensure the following has also been included:
1) Two (2) detachable A.C. linecord
2) Nut driver for output connectors
Please report any damage or missing parts to your dealer immediately.
Place the OMICRON at or near its final set-up position, allowing 8 inches at the rear for
tightening the speaker output connectors.
The power transformers in the OMICRON are located at the front-center of the unit.
Ideally, a few feet should separate this area from components which potentially could pick up hum.
These include preamplifiers, turntables, and interconnect cables. In terms of providing adequate
airspace for cooling, a good rule of thumb is to allow 6 inches above and 3 inches on each side of the
unit.
Check the Serial Number sticker on the back of the unit for the correct operating voltage.
The OMICRON has two external AC fuses, the rating of which should be as follows:
LINE VOLTAGE FUSE RATING
100 or 120 V.A.C. 2X 15 AMP SLOW BLOW, 125 or 250 volts
220 or 240 V.A.C 2X 12 AMP SLOW BLOW, 250 volts

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GENERAL CONNECTIONS
A.C. LINE
Insert the 2 linecords into the A.C. receptacle on the rear of the unit. PLEASE MAKE
SURE YOU HAVE PREVIOUSLY HOOKED UP THE SPEAKERS AND PREAMPLIFIER
TO YOUR AMPLIFIER BEFORE CONNECTING THE AC POWER CORD TO THE
AMPLIFIER.
IMPORTANT NOTE
CAUTION: SAFETY INSTRUCTIONS
DISCONNECT THE 2 AC LINE CABLES BEFORE MAKING ANY OTHER
CONNECTIONS. "FLOATING THE GROUND” OR DEFEATING THE GROUND ON A
3-PRONG LINECORD MAY CREATE A SHOCK HAZARD. CONNECT ALL INTERCON-
NECT CABLES BETWEEN THE ELECTRONICS BEFORE CONNECTING THE A.C.
LINECORDS TO THE WALL OUTLETS. THIS WILL REDUCE THE POTENTIAL SHOCK
HAZARD.
STEREO
Input and output connectors are clearly marked on the back of the amplifier. Left/Right
connections are oriented from the front of the unit. Stereo output connections are marked above the
connectors. Switch stereo/mono switch to STEREO position. (The OMICRON is preset at the
factory for STEREO.)
Use only high quality interconnect and loudspeaker cables, and make all connections tight. If
the RCA input plugs are loose, remove them and pinch down the ground leaves slightly with pliers.
Observe correct phasing of the loudspeaker connections, and tighten.

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STEREO (CONTINUED)
DO NOT OVERTIGHTEN the output connectors. When powering up the OMICRON in stereo
mode, the left channel LED will blink for approximately 20 seconds, when the sequence is
completed, the LED will turn SOLID RED. Then, the right channel LED will also blink for
approximately 20 seconds and will also turn solid red once it has completed its turn on sequence.
MONO
Please read through the previous Stereo section for general notes on securing good
connections, and safety tips. If the unit has been previously used in stereo, make sure it is OFF, and
remove all connections, including the AC line cable. Make sure the STEREO/MONO switch is
switched to the MONO position. NOTE: The Stereo-Mono switch will not operate if the amplifier is
turned on, you will NOT be able to change from one mode to the other, as the mode is “locked”
while the amplifier is on.
When the turn on sequence has been completed with the unit set for MONO operation, only
the CENTER LED will light up.
The MONO "Input" is the "left channel input", as marked. The unused right channel input is
automatically disconnected. Correct output phase MONO connections are marked below the
connectors.
Repeat the above MONO settings and connections on the second OMICRON to be used for
the other channel.
Please remember that the negative output connection of a bridged amplifier is NOT a
ground. Do not use a "common ground” switch-box set-up. Do not use with electronic crossovers
which have a common ground. Connecting two bridged amplifiers to a common ground device of
any sort will cause the amplifiers to fail.

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MONO OPERATION
As stated above, either the regular or balanced inputs can be used in stereo or mono.
Connect a single interconnect, either regular or balanced, to the left channel input of each amplifier.
See the "Mono" section above for complete details. NOTE: Neither the Stereo-Mono switch nor the
REGULAR/ BALANCED switch will operate while the amplifier is turned on. You will NOT be able to
change from one mode to the other, as these modes are “locked” while the amplifier is on. To
activate the circuit, turn off the unit and engage the STEREO/MONO switch to REGULAR. If the unit has
not been turned off before engaging the switch, turn off the unit, wait for about 10 seconds, and turn
the unit on again, the circuit will then engage.

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CONNECTIONS FOR REGULAR OR BALANCED INPUTS:
The CLASSÉ OMICRON power amplifier is equipped with both regular and balanced
inputs. Either one may be used SEPARATELY, BUT NOT SIMULTANEOUSLY. The balanced inputs
must be connected to a preamplifier which has balanced main outputs. Balanced interconnects with
"XLR" connectors are also required. Regardless of the amplifier inputs used, stereo or mono
operation is possible on the OMICRON.
REGULAR INPUTS
Engage the REGULAR/BALANCED switch to the position marked "REGULAR". (The amplifier is
factory set for “REGULAR”.) NOTE: The REGULAR/ BALANCED switch will not operate if the
amplifier is turned on; you will NOT be able to change from one mode to the other, as the mode is
“locked” while the amplifier is on. To activate the circuit, turn off the unit and engage the
REGULAR/BALANCED switch to REGULAR. If the unit has not been turned off before engaging the
switch, turn off the unit, wait for about 10 seconds, and turn the unit on again, the circuit will then
engage. Connect the regular interconnects to the RCA input jacks on the rear panels of the
OMICRON. The balanced connectors are automatically disabled.
BALANCED INPUTS
Switch the
REGULAR/BALANCED switch to the position marked "BALANCED". A balanced
preamplifier and balanced interconnects are also required. NOTE: The REGULAR/ BALANCED switch
will not operate if the amplifier is turned on; you will NOT be able to change from one mode to the
other, as the mode is “locked” while the amplifier is on. If the unit has not been turned off before
engaging the switch, turn off the unit, wait for about 10 seconds, and turn the unit on

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BALANCED INPUTS (CONTINUED)
again, the circuit will then engage. For use with balanced preamplifiers other than Classé, the
wiring of the 3-pin XLR connectors must be matched to that of the CLASSÉ OMICRON which is
wired as follows:
PIN 1: GROUND
PIN 2: POSITIVE (NON-INVERTED) SIGNAL, “HOT”
PIN 3: NEGATIVE (INVERTED) SIGNAL
All Classé preamplifiers and amplifiers are configured as above. Some preamplifiers from other
manufacturers have PIN-3 set as the positive or “HOT” side. If this is true of your preamplifier, and
you wish to maintain absolute phase throughout your system, the interconnects must have the wire
which is connected to PIN-3 at the preamplifier output end switched to PIN-2 at the amplifier input
end and the wire which is connected to PIN-2 at the preamplifier output switched to PIN-3 at the
amplifier input end.
Having confirmed the correct connections, plug the XLR connectors of the balanced
interconnects into the locking XLR connectors on the rear panel of the OMICRON. Push the
connectors in until the locking mechanism clicks. (To remove the connectors, press the tab above the
connector while pulling gently on the connector body.)

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PROTECTION CIRCUIT
A special circuit in the Classé OMICRON continuously monitors the output audio signal to
detect output overload, clipping or DC content. In addition, each channel has two front end supply
voltage fuses, located on the front end voltage regulation board, to protect the input circuitry from
damage due to overload. There is a green LED for the negative voltage supply and a red for the
positive. If a fuse fails, the corresponding LED goes out, alerting you of the fact. (These fuses are 1
amp fast blow).
There are also line AC fuses, located at the rear of the amplifier immediately above each IEC
receptacle. There are no LEDs monitoring the condition of these fuses.
If the protection circuit of the unit is triggered or any of the fuses has blown, the FRONT
PANEL POWER LED(S) will go to BLINKING GREEN, indicating a “fault” condition. If the left
LED is BLINKING GREEN, the fault condition should be located at the left channel, if the right
channel LED is BLINKING GREEN, the fault will be located to the right channel regardless if the
unit is used in mono or stereo.
IF THE PROTECTION CIRCUIT HAS BEEN TRIGGERED, TURN THE OMICRON
OFF. .After the situation which has triggered the protection circuit has been clearly identified and
corrected, attempt to re-start the unit. IF THE UNIT STILL GOES INTO PROTECTION MODE,
OR IF IT APPEARS THAT PROTECTION FUSES DID BLOW, CONTACT YOUR LOCAL
DEALER. DO NOT TRY TO CHANGE A BLOWN FUSE. REPLACING A FUSE WITHOUT
CHECKING FOR COMPONENT FAILURE COULD RESULT IN FURTHER, SERIOUS
DAMAGE TO VITAL COMPONENTS IN YOUR AMPLIFIER. CONTACT YOUR LOCAL
DEALER or Customer Service at the Classé Audio, Inc --- (514) 636-63 84.