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CARVIN ENGINEERING DATA CX672 6CH, CX872 8CH & CX1272 12CH STEREO MIXER OPERATING MANU-
AL
THREE BAND
CHANNEL TONE
CONTROLS
PAD
-20dBPAD SWITCH
HIMID LOW
MICPRE
CHANNEL
LEVEL CHANNEL
EFF SND
CHANNEL
MONITOR
LEVEL
LRMONEFF
EFFECTSSUMMING AMP EFFECTS
SEND 2
LEVEL
MAIN RIGHTSUMMING AMPAND LEVEL
MAIN LEFTSUMMING AMPAND LEVEL
EFFECTS
SEND 2
GAIN STAGE
NINE BAND
GRAPHIC
EQUILIZER
LEFT
LINE OUT
RIGHT
LINE OUT
NINE BAND
GRAPHIC
EQUILIZER
EFFECTS
SEND 2
INTERNAL
DSP SEND GAIN
REDUCTION
FOR DSP
MONITORSUMMING AMP
MONITOR
LINE OUT
LEFT
AMP PATCH
RIGHT
AMP PATCH
DSP RETURN LEFT
DSP RETURN RIGHT
EFFECTS RETURN LEFT
EFFECTS RETURN RIGHT
EFF INPUT LEFT
TAPE RTN RIGHT
TAPE RTN LEFT
STEREO RETURN
FOR INTERNAL
STEREO DSP
RIGHT
TAPE OUT
LEFT
TAPE OUT
TO INTERNAL
POWER AMP
PAN
DSP TO
MONITOR
EFF INPUT RIGHT CX 1BLOPart No.
CHANNEL
line pad
(-26dB)
12340 World Trade Drive, San Diego, CA 92128
(619) 487-1600 (800) 854-2235
www.carvin.com
Congratulations on the purchase of your CX mixer. Your new CX series
mixer demonstrates CARVINÕs commitment to producing the highest
quality and most sophisticated engineering in the audio industry today.
The CX series mixers were designed to be professional mixers in com-
pact units. The CX includes a full function stereo mixer, with two nine
band graphic equalizers, a digital signal effects processor and a powerful
stereo amplifier. A rack mount version is also available without power
amps. Each CX series mixer is surrounded by a strong, lightweight 3/4Ó
poplar plywood cabinet covered with Duratuff IIª carpeting making the
CX mixer road worthy.
CX OVERVIEWThe MIC/LINE input channels feature XLR and 1/4Ó LINE inputs with phantom power for
condenser mics. There are 3 bands of EQ, a post fader effect send, and a monitor pre-
fader send on each channel. The master section features two 9 band graphic EQs, master
stereo main and monitor mix controls, a complete 16 program effects processor with send
and return controls, and a stereo external effects return.
ÒSHELVINGÓ EQ WITH ACTIVE TONE CIRCUITSThe CX series incorporates 3 bands of EQ per channel. They offer smooth tone curves so
your adjustments will sound natural and yet be effective. The high (treble) and low (bass)
ÒshelvingÓ type controls cover the complete upper and bottom portions of the audio range.
The MID EQ controls are a Òband passÓ type which peak at 2.2k Hz for added presence to
your mid range tones. Because CARVIN uses ÒactiveÓ tone circuits, you are able to boost
or cut your tones without any signal loss to your sound.
RECEIVING INSPECTIONÑread before getting startedINSPECT YOUR MIXER FOR ANY DAMAGE which may have occurred during shipping.
If any damage is found, please notify the shipping company and CARVIN immediately.
SAVE THE CARTON & ALL PACKING MATERIALS. In the event you have to re-ship your
unit, always use the original carton and packing material. This will provide the best pos-
sible protection during shipment. CARVIN and the shipping company are not liable for
any damage caused by improper packing.
SAVE YOUR INVOICE. It will be required for warranty service if needed in the future.
SHIPMENT SHORTAGE. If you find items missing, they may have been shipped sepa-
rately. Please allow several days for the rest of your order to arrive before inquiring.
RECORD THE SERIAL NUMBER on the enclosed warranty card or below on this man-
ual for your records. Keep your portion of the card and return the portion with your
name and comments to us.
INTERNAL SIGNAL ROUTINGYour balanced mic or instrument plugs directly into the high quality XLR Neurtricª
connectors and is then routed into the differential circuits for excellent hum and noise
cancellation. As your signal continues within the console, a double-sided printed circuit
board (FR-4 fire rated) carefully guards the circuit traces with a copper shield running
over the traces. This eliminates RF interference and reduces crosstalk substantially. The
printed circuit board has plated-through holes which means that every component is
soldered securely in three places (bottom, in the hole and on top). This offers unsur-
passed component security while reducing circuit resistance for pure dynamic sound.
HEADROOMHeadroom is very important when designing a mixerÑespecially for recording. Lack of
headroom will cause your sound to become distorted and muddy. This can happen when you
turn the volume too high, if the input signal is too hot or if excess bass or treble is added.
With most mixers, you have to reduce the input gain to fight headroom problems, but this
just increases noise. ThatÕs why we have taken great care in the CX series to make sure that
each gain stage is properly designed and balanced for more headroom along the entire audio
path.
TOROID SUPPLYA big feature in the CX power supply is the precision wound Toroid transformer (not
available from our competitors) that offers lighter weight with massive current capabil-
ity for the power amp. The toroid based power supply also offers unsurpassed rejection
of noise and hum while providing precision voltage for all preamp stages. Now you can
go anywhere and never worry about inconsistent sound due to fluctuating voltages.
CARVIN has spared no expense to achieve the best possible quality & performance.
For your records, you may wish to record the following information.
Serial No._____________________ Invoice Date_______________
CX672 / CX872 / CX1272 / CX1272R
76-01272 0798
CX672, CX872 & CX1272 SPECIFICATIONS:
Frequency Response:Mic or Line Inputs: 20Hz-20KHz ±2dB
Total Harmonic Distortion:Less than .1%
Equivalent Input Noise:150 ohm source: -110dBu
Output Noise:-90dBu Master Line Out
(all levels minimum)
Output Power:(Power Mixers Only)
CX872 & CX1272 :8½: 175/175 w, 4½: 250/250 w
2½: 375/375 w, less than 1% THD
Output Headroom:+20dB 1/4Ó unbalanced
Maximum Gain:Mic in to Master Line Out: 70dB
Crosstalk:Adjacent chÕs: -60db at 1KHz
Common Mode Rejection:-80db at 1KHz
Phantom Power:All XLR Mic in channels
Channel EQ.:3 band active, LOW: 80Hz
±12dB
MID: 2.2KHz ±12dB
HI: 11.5KHz ±12dB
Graphic EQ.:9 Band Oct. Intervals ±12dB
Mic Input:Balanced XLR input
Line Input:Unbalanced 1/4Ó Phone Jack
Power Consumption:700VA
Size:11ÓH x 19.5ÓW x9ÓD
Rack Model: 8.75ÓH x 19ÓW x 7.75ÓD CX672, CX872, CX1272 BLOCK DIAGRAM
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QUICK START UPIf youÕre like most new owners, youÕre probably in a hurry to plug
your CX mixer in and use it. Here are some brief instructions to get
you going quickly. With the mixer unplugged and the unit turned off,
complete the following procedures:
1.CONNECTING AC POWER TO YOUR MIXER
¥ Check the rear panel to make sure the mixer has the correct AC
Line Voltage. (120VAC or 240 VAC)
¥ Use only a grounded (3 prong) power outlet to prevent a shock
hazard. This gives the quietest grounding for your mixer.
2.CONNECTING SPEAKERS (Powered Models Only)
¥ Use the 1/4Ó speaker jacks on the rear panel to connect up to four
8½speaker systems per jack (daisy chain). The speaker cables
are to be non-shielded with a minimum size of 16 gauge.
NOTE: Do not run your speakers through microphone wire, gui-
tar cables, or multi-conductor microphone junction boxes
or ÒsnakesÓ as they are sometimes referred to. This wire is nor-
mally shielded and of a very light gauge causing a sub-
stantial loss of power.
3.SpeakerGuardª and the ÒPROTECTÓ LED
¥ The protect LED comes on along with the output relays in three
diff erent protection modes: Shorted speaker outputs,
Speaker Impedance below minimum rating, and when the
amplifier exceeds maximum operating temperature.
¥ In event the LED comes on, turn off the amplifier and Identify and
correct any speaker cable or speaker jack shorts and make sure
the total speaker Impedance for each output is 2 ohms or
greater. Also make sure the fan is not blocked and
check that cool air can circu late around the
rear of the mixer.
4.CONNECTING INPUTS TO YOUR MIXER
¥ For low level balanced devices such as microphones, plug into the
balanced MIC inputs using a shielded microphone cable with XLR
ends.
¥ For high level unbalanced devices such as instruments &
Keyboards plug into the LINE input jacks using a shielded cable
with 1/4Ó phone ends. Set the GAIN switch so the level con-
trol is not over sensitive.
5.TURNING YOUR MIXER ON
¥ Adjust all channel and master level controls to their off positions
¥ Adjust all ÒEQÓ tone controlsÑ the channelÕs Hi, Mid, and Bass
and the two master 9 Band Graphic EQÕs to their center position.
¥ Adjust all the Channel ÒPANÓ controls to their center position.
¥ Set the power amp switch (located next to main volume) out for stereo
mode
¥ Turn the mixer on by the rear panel power switch and watch for
the power LED to come on. Your mixer is now ready to operate.
MIC CHANNEL FEATURES
1. LINE INPUT JACKThe Line input is a 1/4Ó phone jack designed for unbalanced line and
instrument level inputs. Examples of these inputs would be instru-
ments such as a guitar, a keyboard, an unbalanced mic, or a pre-amp
output. The line input can be used at the same time the mic input is
being used.
2. XLR MICROPHONE INPUTThe XLR Mic input is designed for balanced low impedance (micro-
phone) input signals. The differential balanced input amplifier
reduces the common noise picked up on the microphone cables.
The XLR connector is wired as per the industry standard, pin 1 is
ground, pin 2 is non-inverting (positive), and pin 3 is inverting (neg-
ative). Phantom power is available on every XLR input jack when the
phantom power switch in the master section is pressed. This feature
allows condenser microphones to be run directly from the mixer.
Note: When using phantom power, make sure the phantom power is
switched off before connecting or disconnecting microphones to the
mixer. It is recommended to allow 5 seconds for the phantom power
to discharge before making any microphone connections. Also, to
avoid hearing a pop, turn down the master volume when turning on
the phantom power.
3. +20DB GAIN SWITCHThe gain switch increases the input sensitivity on both the line and
mic input jacks by 20dB. After determining the input is too low for
mixing with the level control, turn down the level control, press in
the gain switch, and adjust the level again. If distortion is heard
regardless of the channel level controlÕs setting, disengage this
switch to eliminate over-driving of the input amplifier.
4. CHANNEL LEVEL CONTROLThe Level control adjusts the final volume of the channel beforegoing to the Pan control. Here is where the individual channel vol-
umes are adjusted to make up the desired mix heard at the main
outputs. A general rule to prevent distortion with in the mixer is to
always keep the MAIN master level the same or higher than the
channel LEVEL.
5. MONITOR LEVEL CONTROLThe Mon level control adjusts the volume of the channel going to the
monitor mix. Here is where the individual channel monitor volumes
are adjusted to make up the desired mix heard at the monitor out-
put. The monitor level control is pre-channel level and pre-channel
tone controls. This means it is unaffected by adjustments in channel
level and tone controls. The purpose for this is so the main mix
adjustments for tone and level can be made without disturbing the
monitor mix.
6. CHANNEL PAN CONTROL
The Pan control adjusts where the channel is heard in the stereo
field of the stereo main outputs. If it is turned to the extreme left,
then the channel will only be heard in the left main output and sim-
ilarly only in the right main output if turned to the extreme right. In
the center position the channel is heard equally in both the left and
right main outputs. A good starting point for the pan is in the cen-
ter position. Then if stereo placement is needed, a quarter turn to
the desired side from the center position gives a smooth placement
in the stereo field, or if desired a full turn to one side gives a hard
placement.
7. CHANNEL EFFECTS 1&2 LEVEL CONTROLThe EFF 1&2 control adjusts the volume of the channel going to the
internal effects Send 1 master control, and directly to the EFF SND
2 output. The effects control is post-channel level and automatical-
ly tracks the channelÕs level & tone controls.
8-10. CHANNEL TONE CONTROLSEach channel features active tone controls LO, MID, and HI. Allthree function as boost (clockwise) & cut (counter-clockwise) con-
trols where the center 0 position is neutral. The LO and HI controls
are shelving type tone controls with corner frequencies at 80Hz and
11.5k Hz respectively. The MID control is a band pass type centered
around 2.2kHz. It is suggested the channel tone controls start out
in their center 0 positions. A good setting for added dynamics is to
set the LO & HI at +3, and the MID at -3.
MASTER SECTION FEATURES
11. MAIN MASTER LEVEL CONTROLThe Main control is the master volume control for all channels receiving
the signals from the channel pan controls. The Main feeds the Graphic
EQ, the main line out jacks and the internal power amplifier(s). If the
power amp switch is out, then the Main control sends a stereo mix from
all channels to both power amps. If the power amp switch is pushed in,
then the Main controls sends a mono mix from all channels to the left
power amp only, and the master MONITOR level sends the channel MON
to the right power amp only.
12. POWER AMP INPUT SELECTORThe Power Amp selector selects the inputs to the two graphic EQÕs and
the power amplifiers. The out position is the normal stereo power mixer
mode. The inputs to the two EQÕs are the main left and right signals.
In the push in position the main left/right signals are combined to pro-
duce one mono signal (still controlled by the MAIN control). This mono
signal becomes the input signal to the left EQ (top EQ) and the left
power amp. Also, in the in position the output of the monitor jack and
control knob becomes the input signal for the right EQ and right power
amp.
13. MONITOR MASTER LEVEL CONTROLThe Monitor master level control is the master volume for the mon-
itor mix heard in the monitor output. This volume receives its sig-
nals from the channel monitor level controls. If the power amp
CX672, CX872 & CX1272 CONTROLS
1
2
3
6
5
4
7
8-10
CX672, CX872 & CX1272
