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8
Frequency Response
Input Impedance
All Inputs
Maximum Input Level
All Inputs
Output Impedance
All Inputs
Maximum Output Level
Rise Time
Stereo Separation
Minimum Headphone Impedance
Noise
One Channel Unity Gain
All Channel Unity Gain
T.H.D. + n
Range of Gain Controls
Mute Attenuation
Total Gain
Power Consumption
AC Dropout Voltage
Size
Weight
Shipping Weight
Unit Weight
+ .5 dBm 20 Hz to 20 kHz
+3 dBm 7 Hz to 58 kHz
20 k ohm Unbalanced
+21 dBm
100 ohm
+22 dBm
6 uS
>60 dBm
30 ohms
-81 dBm
-78 dBm
<.01% 20-20kHz
-60 to +18 dBm
60 dBm
36 dBm
.15 Amps Max. A.C. At 120 VAC
.15 Amps Max. A.C. At 230 VAC
+105 VAC at 120 V nominal
+205 VAC at 230 V nominal
Single Space Standard E.I.A Spec
19.0“(482.6mm) Width
6.0“(152.4mm) Depth
1.75“(44.45mm) Height
7.5 lbs (3.40 kg)
6.0 lbs (2.72 kg)
SPECIFICATIONS SUBJECT TO CHANGE WITHOUT NOTICE
SPECIFICATIONS
U.S.Audio
BLOCK DIAGRAM
BUSS
CHANNEL
VOLUME
LEFT
BUSS
RIGHT
LEFT
TOP
RIGHT
MONO
BOTTOM
+
_
+
_
JUMPERS
FOR
120/230
VOLTS
POWER
CHASSIS GROUND
¼ AMP
SLOW
BLOW
HOT
NEG
POWER LED
+18 VOLTS DC
-18 VOLTS DC
BUSS
LEFT
BUSS
RIGHT
MASTER
VOLUME
PHONE
VOLUME
HEAD
+
_
+
_
HEAD
PHONES
SUM AMPS
LEFT
OUT
RIGHT
OUT
The U.S. Audio Mix 8S is a stereo line level eight channel mixer with
separate left and right signal paths. Each of the 8 inputs has left and right
balanced 1/4“ input jacks. For mono input, the right jack can be used
alone and it will ”Y” the signal to both left and right busses. The signal is
actively balanced through differential buffer amps and sent to gain
circuits. Each channel has a dual element level control with a gain range
of -60 to +18 dBm, allowing user control over a wide range of input audio
levels. Unity gain is at the 12 o’clock position for both channel volume
and the master volume.
Signals from individual channels are summed together and delivered to
both master gain stages and to the headphone driver circuit. The left and
right master outputs are controlled by a stereo volume pot which has a
gain range of -60 to +18 dBm. The 60 dBm of attenuation turns off the
audio signal at the main outputs if necessary.
The Mix 8S headphone circuit monitors the left and right busses and will
drive stereo headphones with impedances greater than 30 ohms. The
front panel stereo 1/4“ headphone jack has a volume control with a
range of -60 to +18 dB. The signal going into the headphone circuit is a
pre master fader.
Careful layout of the circuit board and a star grounding scheme ensure
no internal ground loops between channels and / or sections of circuitry.
Using low noise components, noise is 81 dB below 0 dB at unity gain,
with one channel up and 78 dB below 0 dB will all channels up at unity.
The Mix 8s utilizes a dual transformer power supply which is configured
with internal jumpers for 120 VAC 60 Hz or 230 VAC 50 Hz operation.
There is an internal fuse on the hot side of the AC cord, and the power
switch makes and breaks both the hot and neutral legs of the AC cord.
U.S. Audio has made every effort to ensure that your equipment is
received in the same perfect condition it was when it left the factory.
Please inspect your product for any signs of damage during shipping
and report them to your dealer so that a claim can be made to the
shipper. We recommend that you save your packing material for use in
the unlikely event that you need to return your equipment for service.
Thank you for selecting the U.S. Audio Mix 8S stereo line mixer. This
mixer represents an excellent value for monitoring and mixing multiple
stereo feeds, delivering the highest quality audio performance in a
compact one rack space package. The U.S Audio Mix 8 is a true stereo 8
channel line level mixer, designed for use in broadcast production, as a
studio mixdown / monitor mixer for multitrack recorders or in countless
other applications. Features include stereo channel level controls, and a
headphone monitor circuit with individual volume control. The Mix 8S
can provide up to 36 dB of gain, with a professional quality signal to noise
ratio and full frequency response. All connections are made through
balanced 1/4“ tip-ring-sleeve jacks.
INTRODUCTION
UNPACKING
THEORY OF OPERATION
8
99 Ling Road . Rochester, NY 14612 . Phone 716 663-8820 . Fax 716 865-8930 . Email: Sales@whirlwindusa.com . http://www.whirlwindusa.com
1. INPUT LEVEL CONTROL varies the amount of signal sent to the
master left and right busses through a range of 60 dBm attenuation at full
off to +18 dBm of gain full on.
2. MASTER VOLUME CONTROL determines the amount of signal from
the summing amps that is fed to the left and right outputs. This also has a
gain range of -60 to +18 dBm.
3. HEADPHONE VOLUME CONTROL varies the signal at the
headphone jack. The signal going into the headphone circuit is pre
master fader and independent of the master volume pot.
4. POWER LED indicates that the unit is turned on.
5. HEADPHONE JACK drives stereo headphones with impedances
greater than 30 ohms and is wired with left to tip and right to ring.
6. LEFT AND RIGHT INPUT JACKS for each of the 8 channels are
balanced 1/4“ TRS. For mono input, the right jack can be used alone and
it will ”Y” the signal to both inputs.
7. LEFT AND RIGHT MAIN OUT JACKS controlled by the front master
volume pot are balanced 1/4“ TRS and will drive balanced or
unbalanced inputs.
8. POWER SWITCH connects AC to the transformer primary and the
front panel LED indicates that the unit is working. Both sides of the AC
line are switched and the main fuse is located on the circuit board inside
the unit.
9. POWER CORD has a standard 15 amp plug for 120 VAC and has no
plug on the Mix 8S 230 VAC model. Black is line, white is neutral and
green is earth.
CONTROLS AND FUNCTIONS
U.S.Audio
0
1
2
3
4
5
6
7
9
10
8
0
1
2
3
4
5
6
7
9
10
8
0
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2
3
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10
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0
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9
10
8
0
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2
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10
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0
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3
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10
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0
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3
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10
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0
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10
0
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3
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10
8
0
1
2
3
4
5
6
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10
8
PWR
8
CHANNEL 81 2 3
4
5 6
7
MASTER PHONES
CHANNEL CHANNEL CHANNEL CHANNEL CHANNEL CHANNEL CHANNEL
VOLUME VOLUME VOLUME VOLUME VOLUME VOLUME VOLUME VOLUME VOLUME VOLUME
PHONES
PHONES
S
POWER
R
L
8 7 6 5 4 3 2
1
INPUTS
120 Vac at 60 Hz
230 Vac at 50 Hz
25 watts MAX
U.S. AUDIO
A DIVISION OF WHIRLWIND INC
ROCHESTER, NY USA
RIGHT/
LEFT
MONO
MAIN OUT STEREO
ALL CONNECTORS BALANCED
TIP+, RING-, SLEEVE GND
1 2 3 54
678
TM
: TO PREVENT ELECTRIC SHOCK DO NOT
REMOVE COVER. NO USER SERVICEABLE PARTS INSIDE.
REFER SERVICING TO QUALIFIED SERVICE PERSONNEL.
: TO REDUCE THE RISK OF FIRE AND
ELECTRIC SHOCK DO NOT EXPOSE THIS EQUIPMENT TO
ANY TYPE OF RAIN OR MOISTURE.
: DEBRANCHER AVANT D'OUVRIR
WARNING
CAUTION
ATTENTION
TYPICAL OF 8
U.S. AUDIO MIX 8 &16 MANUAL
S
9