whirlwind / U.S. Audio
Operations Manual
MIX-5/MIX-5s
INTRODUCTION
Thank you for sel ecting the US Aud io Mix 5. Both
the Mix 5 Stereo and the Mix 5 Mono offer excellent
value, delivering the highest quality audio
performance at a low cost. Either unit provides up to
55dB of gain, with signal to noise ratios that
approach digital quality and still have 10 to 15dB of
headroom. With a full complement of hook-up
hardware, both mixers are capable of handling any
configuration of line or mic level signals as well as
any combination of balanced or unbalanced XLR and
1/4” connectors.
UNPACKING
US Audio has made every effort to ensure that your
equipment is received in the same perfect condition it
was in when it left the factory. Please inspect your
product for any signs of damage during shipping and
report them to your dealer so that he can present a
claim to the shipper. We recommend that you save
your packaging material for use in the unlikely event
that you will need to return your equipment for
service.
Block Diagram:
Right channel sections and pan pots apply only to the Mix 5 Stereo.
THEORY OF OPERATION
All of the XLR and 1/4” input and output jacks are
active, electronically balanced circuits. The input
section and all critical gain sections of the Mix 5 use
the same IC for gain as top professional mixing
boards. This IC, along with careful component
selection and PC board layout, enables the Mix 5 to
achieve professional quality signal reproduction. All
the gain controls on the Mix 5 (Channel Gain, Aux
and Master) have a range of -60 to +20dBm. With the
input and output switches in the Line position and
both the channel and master volume controls at the
same settings, unity gain is approximately at the 9
O’clock knob position, 10dB gain at 12 O’clock, and
15dB gain at 3 O’clock. At the 5 O’clock position the
unit provides 35dB of gain. The Mic position of the
input switch provides another 20dB for a total of
55dB of gain. This feature allows the Mix 5 to
adequately mix equipment with a wide range of audio
level outputs. 60dB of attenuation in the Off position
allows the Mix 5 to adequately “turn off” line level
signals at the Mix 5 inputs.
The output section of the Mix 5 was designed to
accommodate any configuration – line or mic level;
XLR or ¼”; balanced or unbalanced. Each channel’s
output jacks are individually buffered so that using
any combination of the outputs at any impedance will
not affect the other outputs. With the Mic/Line switch
in the Mic position, the XLR output is reduced 20dB
(this switch does not affect the 1/4” jacks). The Mix 5
uses an H-Pad resister network at the XLR to
maintain the signal to noise ratio, regardless of the
position of the Mic/Line switch. For the XLR
outputs, if ground lifting of pin 1 is desired, jumpers
JMP 84 and JMP 85 inside the unit can be clipped.
Then, in Line mode pin 1 of the XLR is completely
lifted and in Mic mode the XLR’s pin 1 is ground
isolated and referenced to pins 2 and 3. If unbalanced
operation is desired from the XLR outputs, pin 2 is
hot, pin 1 is ground, and pin 3 should be left
UNCONNECTED.
The Mix 5 utilizes a dual primary power transformer
that is configured with internal jumpers for 120 VAC
60Hz or 230 VAC 50Hz 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.
CONTROLS AND CONNECTIONS
1. Channel Volumes control input signals over a range of
60dBm attenuation at full off to 20dBm of gain at full on.
2. Pan Pots (Mix 5 Stereo only) are dual pots with center
detent, providing over 65dB of stereo isolation from left to
right channel. The center detent allows convenient and
accurate setup, feeding signal equally to both channels.
3. Aux Input Pot controls the rear panel RCA input jacks.
Input signals are actively summed in the Mix 5 Mono, and
maintain stereo separation in the Mix 5 Stereo. Again, with
a range of -60 to +20dB of gain, the Mix 5 Aux input will
interface easily with most types of gear.
4. Master Volume Pots (one for Mix 5 Mono) determine
the amount of signal from the summing amps that is fed to
the output drivers and the meters. These also have a gain
range of -60 to +20dBm.
5. LED dB Indicators are precisely calibrated in 3dB
increments and span a range of -15 to + l2dBm, measured
unbalanced with the input switch in Line mode, at either
the 1/4” output or the XLR output. (Add 6 dB for balanced
output).
6. Phantom Power for each of the four input XLR jacks
is activated by the rear panel pushbutton switch. Status is
indicated by the front panel LED. Each channel is
individually filtered to eliminate crosstalk through the
supply rail. The Mix 5 supplies l8VDC with current
limiting resistors chosen to ensure that the phantom supply
will not fall below the AES minimum specification of
l2VDC at a 5.2mA current draw. Most condenser type
microphones draw between 1 and 3mA and will operate
from 12 to 48VDC.
7. Power Switch connects AC to the transformer primary
and the LED indicates that the unit is receiving power.
Both sides of the AC line are switched and a mains fuse is
located on the circuit board inside the unit.
8. Input 1/4” TRS and XLR Jacks are AC-coupled
through phantom blocking capacitors with pin 2 positive,
wired to tip, pin 3 negative, wired to ring, and pin 1
common, wired to sleeve. Audio ground is not connected to
chassis ground.
9. Input Mic/Line Switch is engages an active circuit that
applies 20dB of gain when in the Mic position. This gain is
applied to both input jacks. For most input signals the Out
or Line position will be appropriate.
10. Output Male XLR Jack (left for stereo) is balanced
with pin 2 positive, pin 3 negative and pin 1 audio ground.
For unbalanced operation use pins 1 and 2 leaving pin 3
UNCONNECTED. To internally lift pin 1 from common,
open the unit and cut jumper JMP84.
11. Output Mic/Line Switches affect only the XLR output
jack(s) by inserting a 20dB pad across pins 2 and 3 when in
the Mic position.
12. Output 1/4” TRS Jack delivers the same signal as the
XLR but has a separate driver circuit providing complete
isolation from the XLR output. May be used either
balanced with a TRS plug or unbalanced with a TS plug.
Tip is positive, ring is negative and sleeve is audio ground.
This jack can drive high impedance headphones directly,
although one side is out of phase. A properly wired adapter
cable can provide monitoring capabilities.
13. Output 1/4” TRS Jack is connected to the right output
and is identical to #12 above for the Mix 5 Stereo. It
provides a second active isolated TRS output in the Mix 5
Mono.
14. Output Male XLR Jack and Mic/Line Switch appear
only on the Mix 5 Stereo and operate identically to #10 and
#11 above, providing the right channel output. To internally
lift pin 1 from common, open the unit and cut jumper
JMP85.
15. Power Cord has a standard 15 amp plug for l20VAC
and has no plug on the Mix 5MX or Mix 5sX 230VAC
export models. Black is line, white is neutral and green is
earth.
SPECIFICATIONS
Frequency Response
Line mode ± 3dB, 6Hz to 36kHz
-0.4dB @ 20Hz
-1dB @ 20kHz
Mic mode ± 3dB, 18Hz to 36kHz
-2.5dB @ 20Hz
-1dB @20kHz
Maximum Input Level
Line mode +22 dBm unbalanced
+28 dBm balanced
Mic mode - 2 dBm unbalanced
+4 dBm balanced
Input Impedance
Line mode 2k Ohm balanced or unbalanced
Mic mode 600 Ohm balanced
2k Ohm unbalanced
Maximum Output Level
Balanced +28dBm
Unbalanced +22dBm
Output Impedance XLRs
Line mode 100 Ohms
Mic mode 200 Ohms
Output Impedance TRS
Unbalanced 60 Ohms
Balanced 120 Ohms
Rise Time 8uSec
Stereo Separation >65dBm
C.M.R. (Common Mode Rejection) of Input
> 55dBm @ 60Hz
Attenuation Of Llne/Mic Output Switch
20dBm
Isolation Between 1/4” and XLR Outputs
>l00dBm
Aux Input Impedance 10k Ohms
Maximum Level Aux Input
+22dBm
THD+N (Total Harmonic Distortion + Noise)
Line Mode @ l4dBm of Gain .005%
Line Mode @ Unity Gain .012%
Equivalent Input Noise
Input Level
(dBm)
Input Mic/Line
Switch Position
Gain
(dBm)
Headroom
(dBm)
S/N Ratio
(dBm)
E.I.N.
(dBm)
+ 10
Line 0 13.8 88.3 -88.3
0 Line 0 13.4 87 -87
0 Line 10 12.3 85 -75.3
-10 Line 10 12.2 79.2 -69.2
-20 Mic 30 28 86 -76
-30 Mic 40 12.5 79.7 -69.7
-40 Mic 50 12.7 72.3 -62.3
-10 Line 14 18.4 75.8 -71.8
-10 Mic 14 7.8 84 -80
whirlwind
99 Ling Road
Rochester NY 14612
800 733-9473
www.whirlwindusa.com
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