Samson Musical Instrument MIXPAD User Guide

Produced by On The Right Wavelength for Samson Technologies Corp.  
Copyright 1996, 1997, Samson Technologies Corp.  
Printed February, 1997  
Samson Technologies Corp.  
575 Underhill Blvd.  
P.O. Box 9031  
Syosset, NY 11791-9031  
Phone: 1-800-3-SAMSON (1-800-372-6766)  
Fax: 516-364-3888  
 
Introduction  
Congratulations on your purchase of the Samson MIXPAD! One of the  
smallest mixers ever made, the MIXPAD provides excellent sound  
quality and a wealth of features normally found only in full-size units.  
Although it has been designed for easy operation, we suggest you take  
some time to go through these pages so you can fully understand how  
we’ve implemented a number of unique functions.  
This manual covers three models: the MIXPAD 12, MIXPAD 9, and  
MIXPAD 4. The first two of these are identical apart from the fact that  
the MIXPAD 12 provides six monophonic and three stereo input  
channels (for a total of twelve channels), while the MIXPAD 9 provides  
three monophonic and three stereo input channels (for a total of nine  
channels). The MIXPAD 4 provides two monophonic input channels  
and one stereo input channel (for a total of four channels) and offers a  
slightly different feature set (such as three-band equalization and  
independent channel phantom power switches). Because of their  
unusually small size and portability, all three models are well-suited for  
specialized applications such as videography, remote site recording,  
ENG (Electronic News Gathering), or audio coverage of fast-paced  
outdoor events such as sports shows.  
In these pages, we’ll provide you with an overview of the unit’s features,  
followed by a guided tour of the MIXPAD channels, main section and  
jackfield. Then we’ll describe how to set up your MIXPAD, including  
instructions on how to set the optimum gain structure. Next, we’ll cover  
a number of specific MIXPAD functions (such as panning, equalization,  
and auxiliary sends and returns) in detail. Finally, we’ll wrap things up  
with full specifications. You’ll also find a warranty card enclosed—  
please don’t forget to fill it out and mail it so that you can receive online  
technical support and so we can send you updated information about  
these and other Samson products in the future.  
SPECIAL NOTE: Should your MIXPAD ever require servicing, a Return  
Authorization (RA) number is necessary. Without this number, the unit  
will not be accepted. Please call Samson at 1-800-372-6766 for a  
Return Authorization number prior to shipping your unit. Please retain  
the original packing materials and, if possible, return the unit in its  
original carton and packing materials.  
1
 
MIXPAD Fe ature s  
The compact design of the MIXPAD belies an extraordinary versatility.  
Add excellent sound quality to the equation, and you’ve got a product  
which is equally useful as a live performance mixer and for field  
recording applications. Here are some of the MIXPAD’s main features:  
• In the MIXPAD 12, a total of twelve input channels (including three  
stereo channels); in the MIXPAD 9, a total of nine input channels  
(including three stereo channels); in the MIXPAD 4, a total of four  
input channels (including one stereo channel). Monophonic  
channels provide electronically balanced inputs that can be used for  
microphone or line-level input, while stereo channels are ideal for  
line-level sources such as outboard signal processors; CD players;  
tape or cassette recorders; stereo drum machines; and keyboards  
and MIDI tone modules.  
• An electronically balanced main stereo output for connection to a  
power amplifier or tape recorder.  
• A dedicated Tape/CD input for playback of prerecorded material.  
• In the MIXPAD 12 and MIXPAD 9, two auxiliary sends and two  
stereo auxiliary returns (which can be used as four monophonic  
returns). Aux send 1 is pre-fader (but post-equalizer), making it ideal  
for use as a headphone or monitor cue mix, while Aux send 2 is  
post-fader and post-equalizer.  
• In the MIXPAD 4, one auxiliary send and one stereo auxiliary return  
(which can be used as two monophonic returns), with the aux send  
post-fader and post-equalizer.  
• In the MIXPAD 12 and MIXPAD 9, independent 2-band equalization  
for each channel, with 15 dB of cut or boost for low (100 Hz) and  
high (10 kHz) frequencies.  
• In the MIXPAD 4, independent 3-band equalization for each channel,  
with 15 dB of cut or boost for low (80 Hz) and high (12 kHz)  
frequencies, and 12 dB of cut or boost for the mid (2.5 kHz)  
frequency.  
2
 
MIXPAD Fe ature s  
• Constant level pan controls for placing each monophonic channel in  
the left-right stereo spectrum, as well as balance controls that allow  
you to blend the relative levels of stereo inputs.  
• Mic input trims that are continuously adjustable from +4 to -50 dB,  
making it possible to use the MIXPAD with a wide variety of  
microphones.  
• The MIXPAD 12 and MIXPAD 9 provide 36 volts of phantom power  
to all mic inputs, while the MIXPAD 4 provides 18 volts of phantom  
power (with independent switches for each of its two mic input  
channels), making it possible to use most condenser and dynamic  
mics, as well as active DI (Direct Injection) boxes.  
• Peak LEDs for the left and right main outputs, showing you when  
signal is overloading or near overloading.  
• Center detents for all pan, balance, and EQ controls, making it  
easy to access them in low-light situations such as live performance.  
• Convenient front-panel Power switch, Power LED and dedicated  
headphone jack.  
• The MIXPAD 4 runs on either AC or battery power (requiring just two  
standard 9 volt batteries—three if you need phantom power), with  
optional battery power available for the MIXPAD 12 and MIXPAD 9  
(see Appendix A on page 34), enabling the unit to be used for  
ENG (Electronic News Gathering), field broadcast and recording  
purposes. In the MIXPAD 4, the front-panel Power LED also  
indicates battery strength.  
• The MIXPAD 4 includes a handy carrying strap for easy portability.  
• Last but certainly not least, affordability. The Samson MIXPAD  
has been designed from the ground up to provide versatility and  
excellent sound quality at a cost-conscious price.  
3
 
Guide d Tour -  
MIXPAD 12 / MIXPAD 9 Channe ls  
1
M IC  
-1  
0
0
2
3
T R IM  
+4  
-5  
0
L
M
O
N
O
R
L IN E  
O
O
-1  
5
+1 5  
-1  
5
+1 5  
H IG H  
H IG H  
4
5
O
O
-1  
5
+1  
O
5
-1  
5
+1  
O
5
L O W  
L O W  
+1  
0
+1  
0
A U X 1  
P
R
O
E
A U X 1  
P
R
O
E
+1  
0
+1  
0
A U X  
2
A U X  
2
6
L
R
L
R
7
P A N  
B A L A N C E  
O
O
8
+1  
0
+1  
0
L E V E L  
L E V E L  
Mono Channel  
Stereo Channel  
4
 
Guide d Tour -  
MIXPAD 12 / MIXPAD 9 Channe ls  
1: Mic inputs - Provided in monophonic channels only (channels 1 - 6  
in the MIXPAD 12 and channels 1 - 3 in the MIXPAD 9). Use these  
electronically balanced XLR jacks to connect microphones to any of the  
MIXPAD’s monophonic channels. These are intended to accept signal  
from low-level, low-impedance mics but can also be used for signal from  
other sources (such as direct injection boxes) if the channel’s Trim  
control is turned down (see #2 below). All MIXPAD 12 and MIXPAD 9  
XLR mic connectors are 36 volt phantom powered, enabling you to  
connect a wide variety of condenser or dynamic microphones.  
WARNING: Do not connect a channel’s microphone input if you  
already have something connected to its line input; each channel is  
designed to accept only one source or the other.  
2: Trim - Provided in monophonic channels only (channels 1 - 6 in the  
MIXPAD 12 and channels 1 - 3 in the MIXPAD 9). This knob  
determines the input level of the connected mic or line signal.  
Continuously adjustable from +4 dB to -50 dB, the input trim is at unity  
gain (no boost or cut) when set to the “0” (9 o’clock) position. The input  
signal is boosted when the trim is turned to the right of “0” and  
attenuated when turned to the left of “0.” For information on how to  
properly set this for each channel, see the section on page 23 entitled  
“Setting The Correct Gain Structure.”  
3: Line inputs - Use these standard 1/4" jacks to connect line-level  
sources such as synthesizers, drum machines, CD players, tape decks,  
or effects processors to any of the MIXPAD’s mono or stereo channels.  
The line input jacks for monophonic channels (channels 1 - 6 in the  
MIXPAD 12 and channels 1 - 3 in the MIXPAD 9) are electronically  
balanced, so you should use balanced three-conductor cabling and  
Tip/Ring/Sleeve (TRS) plugs wherever possible (unbalanced two-  
conductor plugs can also be inserted into these inputs, but you’ll get  
better signal quality and less outside noise and hum if you use balanced  
lines). WARNING: Do not connect a channel’s line input if you already  
have something connected to its microphone input; each channel is  
designed to accept only one source or the other.  
The line input jacks for stereo channels (channels 7 - 12 in the  
MIXPAD 12 and channels 4 - 9 in the MIXPAD 9) are unbalanced.  
When connecting only one monophonic signal to stereo channels, use  
the left (even-numbered) input; the MIXPAD will then treat that channel  
as if it is a mono channel, allowing the signal to be panned (using the  
5
 
Guide d Tour -  
MIXPAD 12 / MIXPAD 9 Channe ls  
Balance control)—see the “Using Pan/Balance” section on page 28 for  
more information. See the “Connecting The MIXPAD” section on page  
19 for additional information on how best to use channel inputs.  
4: Equalizer (violet) - These knobs determine the amount of boost or  
attenuation in each of two frequency areas. The high and low frequency  
knobs provide 15 dB of cut or boost at 10 kHz and 100 Hz, respectively.  
Both frequency controls utilize a shelving curve. In stereo channels, EQ  
settings affect both the left and right inputs, although the signals remain  
separate. A center detent in each knob (at the “0” position) indicates no  
boost or attenuation (that is, flat response). As each knob is turned  
clockwise from the “0” position, the frequency area is boosted; as it is  
turned counterclockwise from the “0” position, the frequency area is  
attenuated. For more information on the application of EQ, see the  
“Using Equalization” section on page 30.  
5: Auxiliary sends (blue) - These knobs allow you to route signal to  
either or both of the MIXPAD’s two monophonic Auxiliary outputs.  
These are typically used to create submixes (for example, a headphone  
cue mix) and to feed signal from single or multiple channels to outboard  
effects devices. At the “0” (2 o’clock) position, the signal is routed with  
unity gain (that is, no boost or attenuation). As each knob is turned  
clockwise from the “0” position, the signal is boosted; as it is turned  
counterclockwise from the “0” position, it is attenuated. Aux send 1 is  
post-eq but pre-fade; that is, the level of the signal is determined solely  
by its EQ settings and by its Trim control; see #2 on the previous page.  
Aux send 2 is post-eq and post-fade; that is, the level of the signal is  
determined by the channel’s Trim control, its EQ settings, and the  
position of its Level control. See the “Using Aux Sends and Returns”  
section on page 32 for more information.  
6: Pan (green) - Provided in monophonic channels only. This knob  
allows you to place the input signal anywhere in the left-right stereo  
spectrum, while keeping the overall signal level constant. When the  
knob is placed at its center (detented) position, the signal is sent equally  
to both left and right outputs. When moved left of center, less signal is  
sent to the right output and more signal is sent to the left output (making  
the sound appear left of center) and when moved right of center, less  
signal is sent to the left output and more signal is sent to the right output  
(making the sound appear right of center). To route a signal hard left or  
right, place the pan knob either fully counterclockwise or fully clockwise.  
6
 
Guide d Tour -  
MIXPAD 12 / MIXPAD 9 Channe ls  
7: Balance (brown) - Provided in stereo channels only. When both  
inputs are connected to a stereo channel, the upper input signal  
(channels 7, 9, and 11 in the MIXPAD 12 and channels 4, 6, and 8 in  
the MIXPAD 9) is automatically panned hard left and the lower input  
signal (channels 8, 10, and 12 in the MIXPAD 12 and channels 5, 7, and  
9 in the MIXPAD 9) is automatically panned hard right. In this case, the  
“Balance” knob controls the relative levels of the paired input signals.  
When the knob is placed at its center (detented) position, both signals  
are at equal strength. When moved left of center, the upper input  
remains at the same strength but the lower input is attenuated; when  
the knob is moved right of center, the lower input remains at the same  
strength but the upper input is attenuated. When placed fully  
counter-clockwise, only the upper input is heard (panned hard left);  
when placed fully clockwise, only the lower input is heard (panned  
hard right). In stereo channels where only the upper input is connected,  
the Balance knob works like a mono channel Pan control; see #6 on the  
previous page for details. For more information, see the “Using  
Pan/Balance” section on page 28 in this manual.  
8: Level (white) - In mono channels (or in stereo channels where only  
the upper input is connected), this knob determines the signal level  
being sent to the main output as well as affecting the signal level being  
sent to Aux send 2. In stereo channels, this knob simultaneously  
controls the level of both the upper and lower inputs (the relative levels  
of the two can be adjusted with the Balance knob, as described above)  
as well as the signal level being sent to Aux send 2. In practice, you will  
use the channel Level controls to continuously adjust the levels of the  
various signals being blended together by the MIXPAD. The “0”  
position of the knob indicates unity gain (no level attenuation or boost).  
Moving the knob counterclockwise from the “0” position causes the  
signal to be attenuated (at the very bottom, it is attenuated infinitely—  
in other words, there is no sound); moving it clockwise from the “0”  
position causes the signal to be boosted by as much as 10 dB.  
For best signal-to-noise ratio, all Level controls for channels  
carrying signal should generally be kept at or near the “0” position.  
Channels that are unused should have their gain controls kept fully  
counterclockwise at their (minimum) level. See the “Setting the  
Correct Gain Structure” section on page 23 in this manual for more  
information.  
7
 
Guide d Tour - MIXPAD 12 /  
MIXPAD 9 Main Se ction  
T A P E /C D  
1
L E F T  
L E F T  
R IG H T  
R IG H T  
2
4
3
P O W E R  
O
+1  
0
A U X R E T . 1 /2  
5
O
+1  
0
A U X R E T .  
3
/4  
6
7
O
+1  
0
M A IN L E V E L  
1: Tape/CD inputs (L, R) - Use this set of dual RCA jacks to connect  
the outputs of a tape or CD player to the MIXPAD. In the MIXPAD 12,  
signal connected here appears at stereo channel 11/12 and is mixed at  
unity gain with any line input signal connected to channel 11/12. In the  
MIXPAD 9, signal connected here appears at stereo channel 8/9 and is  
mixed at unity gain with any line input signal connected to channel 8/9.  
8
 
Guide d Tour - MIXPAD 12 /  
MIXPAD 9 Main Se ction  
2: Left/Right Peak LEDs (red) - These warning lights indicate an  
overload situation. They light whenever the main left or right output  
signal is 5 dB short of clipping. To stop them from lighting (and to  
eliminate the accompanying sonic distortion), turn down the Main Level  
control (see #7 below). See the “Setting the Correct Gain Structure”  
section on page 23 in this manual for more information.  
3: Power LED - This LED lights steadily red whenever the MIXPAD is  
powered on.  
4: Power on-off switch - As you may have guessed, this is what you  
use to turn the MIXPAD on and off. To avoid potential damage to your  
speakers, turn the unit on before you turn on any connected power  
amps—and turn it off after the power amps are turned off.  
5: Stereo Auxiliary Return Level (tan) - These knobs determine the  
input level of signal arriving via the MIXPAD’s two stereo Auxiliary  
returns (1/2 and 3/4). Each return is at unity gain (no boost or attenua-  
tion) when set to the “0” (2 o’clock) position. The input signal is boosted  
when the knob is turned to the right of “0” and attenuated when turned  
to the left of “0.” For information on how to properly set these, see the  
sections in this manual entitled “Setting the Correct Gain Structure” and  
“Using the Aux Sends and Returns” (pages 23 and 32). Auxiliary return  
signal is automatically routed to the Main L/R output.  
6: Headphone jack - Connect any standard stereo headphones to this  
jack (via a standard 1/4" TRS plug) for private monitoring of the main  
stereo output. The built-in MIXPAD headphone preamp delivers  
100 mw at 600 ohms.  
7: Main Level (white) - This knob determines the final output signal  
level—you can think of this as being the “master fader.” Signals from all  
channels and Auxiliary returns, as well as the Tape/CD input are routed  
here just before leaving the MIXPAD via its left and right main output  
jacks. The “0” position of the knob indicates unity gain (no level attenu-  
ation or boost). Moving the knob counterclockwise from the “0” position  
causes the signal to be attenuated (at the very bottom, it is attenuated  
infinitely—in other words, there is no sound). Moving it clockwise from  
the “0” position causes the signal to be boosted by as much as 10 dB.  
For more information, see the “Setting The Correct Gain Structure”  
section on page 23 in this manual.  
9
 
Guide d Tour -  
MIXPAD 12 / MIXPAD 9 Jackfie ld  
2
1
O
A
U
L A  
+4 d B  
T P  
N
U
C
u
T
E D  
A U X  
S E N D  
A U X  
S E N D  
R IG H T  
L E F T  
B
1
2
A
U
X
R
E T U  
R
N
1
/2  
A
U
X
R
E T U  
R
N
3
3
/4  
1: Aux Sends (1, 2) - These unbalanced 1/4" outputs allow you to route  
signal from each of the two discrete Aux Sends to external devices such  
as effects processors. Aux send 1 is pre-fade but post-EQ, while Aux  
send 2 is both post-fade and post-EQ. See the “Using the Aux Sends  
and Returns” section on page 32 in this manual for more information.  
2: Main out (L, R) - These are the MIXPAD’s main outputs. You’ll  
usually use these to connect the MIXPAD to a tape recorder or to a  
power amp and loudspeakers. The Main out jacks are electronically  
balanced, so you should use balanced three-conductor cabling and TRS  
plugs wherever possible (unbalanced two-conductor plugs can also be  
inserted into these outputs, but you’ll get better signal quality and less  
outside noise and hum if you use balanced lines). See the “Connecting  
the MIXPAD” section on page 19 in this manual for more information.  
3: Aux Returns (1/2, 3/4) - These inputs allow you to route signal from  
external devices such as effects processors to either of the MIXPAD's  
two stereo Aux Returns. These jacks accept unbalanced 1/4" TRS  
plugs, with the tip carrying the left signal and the ring carrying the right  
signal (sleeve is common ground). See the “Using the Aux Sends and  
Returns” section on page 32 in this manual for more information.  
10  
 
Conne cting the MIXPAD 4  
Carrying Strap  
X
L
R
/
L
I
N
E
I
N
P
U
D
T
M IX P A D  
4
2
/
/
T
I
P
N
+
-
1
5
A V I S ;  
3
R
I
G
R I S Q U E D E C H O C E L E C T R I Q U E  
N E P A S O U V R I R  
D O N O T E X P O S E T H I S E Q U I P M E N T  
T O R A I N O R M O I S T U R E  
1
/
S
L
E
E
V
D
E
G
E
N
2
4
A
U
X
S
I
E
N
/
R
T
+
U
R
N
3
T
L
P
S
E
E
V
E
G
N
D
.
D . C . I N P U T  
P I N  
P I N  
P I N  
1
+ 1 5 V  
- 1 5 V  
G N D  
P I N  
P I N  
4
+ 3 2 V  
G N D  
S / N  
2
3
5
D C I N P U T  
A
The MIXPAD 4 is supplied with a handy carrying strap for easy  
portability. As shown in the illustration above, attach the strap to the  
MIXPAD 4 by placing the buckles in the connector slots and pressing  
them in firmly until they snap in place. Remove the carrying strap by  
gently squeezing together the outside buckle clips in order to extract  
them from the connector slots.  
11  
 
Guide d Tour -  
MIXPAD 4 Channe ls  
1
MIC  
-20  
-10  
0
2
3
-50  
TRIM -6  
4R  
3L  
LINE  
LINE  
O
O
-15  
+15  
-15  
+15  
HIGH  
HIGH  
O
O
4
5
-12  
+12  
-12  
+12  
MID  
MID  
O
O
-15  
+15  
O
-15  
+15  
LOW  
LOW  
O
+10  
+10  
AUX  
AUX  
6
7
L
R
L
R
PAN  
BALANCE  
O
O
8
+10  
+10  
LEVEL  
LEVEL  
12  
 
Guide d Tour -  
MIXPAD 4 Channe ls  
1: Mic inputs - Provided in monophonic channels only (channels 1 and  
2). Use these electronically balanced XLR jacks to connect microphones  
to either of the MIXPAD 4’s two monophonic channels. These are  
intended to accept signal from low-level, low-impedance mics but can  
also be used for signal from other sources (such as direct injection  
boxes) if the channel’s Trim control is turned down (see #2 below).  
When the channel’s Phantom Power switch is pressed in (see #2 on  
page 16), 18 volts of phantom power is delivered to pins 2 and 3 of that  
channel’s XLR mic input, enabling you to connect most condenser  
microphones. WARNING: Do not connect a channel’s microphone  
input if you already have something connected to its line input; each  
channel is designed to accept only one source or the other.  
2: Trim - Provided in monophonic channels only (channels 1 and 2).  
This knob determines the input level of the connected mic or line signal.  
Continuously adjustable from -6 dB to -50 dB, the input trim is at unity  
gain (no boost or cut) when set to the “0” (9 o’clock) position. The input  
signal is boosted when the trim is turned to the right of “0” and  
attenuated when turned to the left of “0.” For information on how to  
properly set this for each channel, see the section on page 23 in this  
manual entitled “Setting The Correct Gain Structure.”  
3: Line inputs - Use these 1/4" jacks to connect line-level sources such  
as synthesizers, drum machines, CD players, tape decks, or effects  
processors to any of the MIXPAD’s mono or stereo channels. The line  
input jacks for monophonic channels (channels 1 - 2) are electronically  
balanced, so you should use balanced three-conductor cabling and  
Tip/Ring/Sleeve (TRS) plugs wherever possible (unbalanced two-  
conductor plugs can also be inserted into these inputs, but you’ll get  
better signal quality and less outside noise and hum if you use balanced  
lines). WARNING: Do not connect a channel’s line input if you already  
have something connected to its microphone input; each channel is  
designed to accept only one source or the other.  
The line input jack for the stereo channel (channels 3 - 4) accepts a  
single unbalanced 1/4" TRS plug, with the tip carrying the left signal and  
the ring carrying the right signal (sleeve is common ground). See the  
“Connecting The MIXPAD” section on page 19 in this manual for  
additional information on how best to use channel inputs.  
13  
 
Guide d Tour -  
MIXPAD 4 Channe ls  
4: Equalizer (violet) - These knobs determine the amount of boost or  
attenuation in each of three frequency areas. Each knob provides  
15 dB of cut or boost at 12 kHz (High) and 80 Hz (Low) frequencies,  
and 12 dB of cut or boost at the Mid (2.5 kHz) frequency. The High and  
Low frequencies utilize shelving curves and the Mid frequency utilizes a  
bell (peaking) curve. In the stereo channel (channels 3 - 4), the EQ  
settings affect both inputs, although the signals remain separate.  
A center detent in each knob (at the “0” position) indicates no boost or  
attenuation (that is, flat response). As each knob is turned clockwise  
from the “0” position, the frequency area is boosted; as it is turned  
counterclockwise from the “0” position, the frequency area is  
attenuated. For more information on the application of EQ, see the  
“Using Equalization” section on page 30 in this manual.  
5: Auxiliary send (blue) - This knob allows you to route signal from  
any or all channels to the MIXPAD 4’s monophonic Auxiliary output.  
This is typically used to create a submix (for example, a headphone cue  
mix) or to feed signal from single or multiple channels to outboard  
effects devices. At the “0” (2 o’clock) position, the signal is routed with  
unity gain (that is, no boost or attenuation). As each knob is turned  
clockwise from the “0” position, the signal is boosted; as it is turned  
counterclockwise from the “0” position, it is attenuated. The MIXPAD 4  
Aux send is post-eq and post-fade; that is, the level of the signal is  
determined by the channel’s EQ settings and the position of its Level  
control (plus, in mono channels, the position of its Trim control).  
See the “Using Aux Sends and Returns” section on page 32 for more  
information.  
6: Pan (green) - Provided in monophonic channels (channels 1 - 2)  
only. This knob allows you to place the input signal anywhere in the  
left-right stereo spectrum, while keeping the overall signal level  
constant. When the knob is placed at its center (detented) position, the  
signal is sent equally to both left and right outputs. When moved left of  
center, less signal is sent to the right output and more signal is sent to  
the left output (making the sound appear left of center) and when moved  
right of center, less signal is sent to the left output and more signal is  
sent to the right output (making the sound appear right of center).  
To route a signal hard left or right, place the pan knob either fully  
counterclockwise or fully clockwise.  
14  
 
Guide d Tour -  
MIXPAD 4 Channe ls  
7: Balance (brown) - Provided in the stereo channel (channels 3 - 4)  
only. When both inputs are connected to the stereo channel, the  
channel 3 input signal is automatically panned hard left and the channel  
4 input signal is automatically panned hard right. In this case, the  
“Balance” knob controls the relative levels of the paired input signals.  
When the knob is placed at its center (detented) position, both signals  
are at equal strength. When moved left of center, the channel 3 input  
remains at the same strength but the channel 4 input is attenuated; when  
the knob is moved right of center, the channel 4 input remains at the  
same strength but the channel 3 input is attenuated. When placed fully  
counter-clockwise, only the channel 3 input is heard (panned hard left);  
when placed fully clockwise, only the channel 4 input is heard (panned  
hard right). For more information, see the “Using Pan/Balance” section  
on page 28 in this manual.  
8: Level (white) - This knob determines the signal level being sent to the  
main output. When both channels are connected in the stereo channel ,  
this knob simultaneously controls the level of both inputs (the relative  
levels of the two can be adjusted with the Balance knob, as described  
above). In practice, you will use the channel Level controls to  
continuously adjust the levels of the various signals being blended  
together by the MIXPAD 4. The “0” position of the knob indicates unity  
gain (no level attenuation or boost). Moving the knob counterclockwise  
from the “0” position causes the signal to be attenuated (at the very  
bottom, it is attenuated infinitely—in other words, there is no sound);  
moving it clockwise from the “0” position causes the signal to be boosted  
by as much as 10 dB.  
For best signal-to-noise ratio, all Level controls for channels  
carrying signal should generally be kept at or near the “0” position.  
Channels that are unused should have their gain controls kept fully  
counterclockwise at their (minimum) level. See the “Setting the  
Correct Gain Structure” section on page 23 in this manual for more  
information.  
15  
 
Guide d Tour -  
MIXPAD 4 Main Se ction  
TAPE/CD INPUT  
1
3L  
4R  
PHANTOM POWER  
2
CH1  
L
CH2  
R
3
5
PEAK  
4
POWER  
O
6
7
+10  
AUX RET 1/2  
O
8
+10  
MAIN LEVEL  
1: Tape/CD inputs (L, R) - Use this set of dual RCA jacks to connect  
the outputs of a tape or CD player to the MIXPAD 4. Signal connected  
here appears at the stereo channel (channels 3 and 4) and is mixed at  
unity gain with any line input signal connected to channel 3/4.  
2: Phantom Power switches (Ch 1, Ch 2) - When pressed in, 18 volts  
of phantom power is delivered to pins 2 and 3 of the XLR mic connector  
of the selected channel. WARNING: Only use this switch with the  
MIXPAD 4 powered down. Before turning phantom power on, be sure  
to disconnect all non-microphone signal sources (such as passive direct  
injection boxes) from the XLR mic jacks. Although phantom power will  
have no adverse affect on connected dynamic microphones, it should  
be used only when one or more condenser microphones are connected  
to the MIXPAD 4. Refer to the owners manual of your microphone  
or active direct injection (DI) box to determine whether or not it  
requires 18 volts of phantom power—Samson cannot assume  
responsibility if you damage a mic or DI box by incorrectly  
applying phantom power from the MIXPAD 4. If you’re not  
completely certain that one or more connected mics or active DI boxes  
require 18 volts phantom power, leave this switch off (its out position).  
16  
 
Guide d Tour -  
MIXPAD 4 Main Se ction  
3: Left/Right Peak LEDs (red) - These warning lights indicate an  
overload situation. They light whenever the main left or right output  
signal is 5 dB short of clipping. To stop them from lighting (and to  
eliminate the accompanying sonic distortion), turn down the Main Level  
control (see #8 below). See the “Setting the Correct Gain Structure”  
section on page 23 in this manual for more information.  
4: Power LED (green) - This LED indicates battery strength. It flashes  
briefly whenever the MIXPAD 4 is powered on and lights steadily when  
the batteries are low and need replacing.  
5: Power on-off switch - As you may have guessed, this is what you  
use to turn the MIXPAD 4 on and off. To avoid potential damage to your  
speakers, turn the unit on before you turn on any connected power  
amps—and turn it off after the power amps are turned off.  
6: Stereo Auxiliary Return Level (tan) - This knob determines the input  
level of signal arriving via the MIXPAD 4’s stereo Auxiliary return. The  
Aux return is at unity gain (no boost or attenuation) when set to the “0”  
(2 o’clock) position; the signal is boosted when the knob is turned to the  
right of “0” and attenuated when turned to the left of “0.” For information  
on how to properly set this, see the sections in this manual entitled  
“Setting the Correct Gain Structure” and “Using Aux Sends and Returns”  
(pages 23 and 32). Note that signal applied to the Aux return is  
automatically routed to the Main L/R output.  
7: Headphone jack - Connect any standard stereo headphones to this  
jack (via a standard 1/4" TRS plug) for private monitoring of the main  
stereo output (pre-Main Level). The built-in MIXPAD 4 headphone  
preamp delivers 38 mw at 600 ohms.  
8: Main Level (white) - This knob determines the final output signal  
level—you can think of this as being the “master fader.” Signals from all  
channels and the Aux return, as well as the Tape/CD input are routed  
here just before leaving the MIXPAD 4 via its left and right main output  
jacks. The “0” position of the knob indicates unity gain (no level  
attenuation or boost). Moving the knob counterclockwise from the “0”  
position causes the signal to be attenuated (at the fully counterclockwise  
position, it is attenuated infinitely—in other words, there is no sound).  
Moving it clockwise from the “0” position causes the signal to be boosted  
by as much as 10 dB. Note that the Main Level control has no effect on  
the headphone level. For more information, see the “Setting The Correct  
Gain Structure” section on page 23 of this manual.  
17  
 
Guide d Tour -  
MIXPAD 4 Jackfie ld  
1
MAIN OUTPUT  
BALANCED +4dBu  
LEFT  
RIGHT  
AUX SEND  
AUX RET 1/MONO  
3
2
AUX RET 2  
1: Main out (L, R) - These are the MIXPAD 4’s main outputs. You’ll  
usually use these to connect the MIXPAD 4 to a tape recorder or to a  
power amp and loudspeakers. The Main out jacks are electronically  
balanced, so you should use balanced three-conductor cabling and  
TRS plugs wherever possible (unbalanced two-conductor plugs can also  
be inserted into these outputs, but you’ll get better signal quality and  
less outside noise and hum if you use balanced lines). See the  
“Connecting the MIXPAD” section on page 19 for more information.  
2: Aux Send - This unbalanced 1/4" output allows you to route signal  
from any or all channels to external devices such as effects processors.  
The MIXPAD 4 Aux send is post-fade and post-EQ. See the “Using Aux  
Sends and Returns” section on page 32 for more information.  
3: Aux Return (1/Mono / 2) - These unbalanced 1/4" inputs allow you  
to route signal from external devices such as effects processors to the  
MIXPAD 4’s stereo Aux Return. When connecting only a single mono  
signal to the Aux Return, use the “ Aux Ret. 1/Mono” input; the signal  
will then be automatically panned dead center. When connecting stereo  
signals, use both jacks; the signal connected to the “Aux Ret. 1/Mono”  
jack will be automatically panned hard left and the signal connected to  
the “Aux Ret 2” jack will be automatically panned hard right. See  
“Using Aux Sends and Returns” on page 32 for more information.  
18  
 
Conne cting the MIXPAD -  
Ge ne ral Sugge s tions  
The actual connections you’ll make to and from the MIXPAD will vary  
according to the environment you use it in and the particular equipment  
you have, but here are a few basic rules concerning MIXPAD  
connections that will apply in most situations:  
• In general, it’s best to make all connections with the MIXPAD and  
any connected power amplifiers turned off. If you must make  
connections with the power on, make sure that the Main Level  
control is completely down (turn the knob fully counterclockwise).  
Whenever powering down, turn the Main Level control completely  
down and turn off the main power amps first. Wait a few seconds  
for their power supplies to discharge and then turn off all connected  
equipment, turning the MIXPAD off last.  
• Try to use balanced connectors and cabling wherever possible.  
These kind of connections do a better job of rejecting extraneous  
noise and hum and generally provide a cleaner signal. Although  
the MIXPAD will accept unbalanced connectors throughout, it  
specifically provides electronically balanced inputs for all mono line  
inputs (channels 1 - 6 in the MIXPAD 12; channels 1 - 3 in the  
MIXPAD 9; and channels 1 - 2 in the MIXPAD 4) and for its main  
outputs. The wiring diagram below shows how 1/4" TRS  
(Tip/Ring/Sleeve) connectors should be wired for use with these  
inputs and outputs:  
SLEEVE  
RING  
TIP +  
TIP  
GROUND  
RING -  
Unbalanced cables use standard 1/4" phone connectors, wired as  
follows:  
+ SIGNAL  
GROUND  
+ SIGNAL  
GROUND  
19  
 
Conne cting the MIXPAD -  
Ge ne ral Sugge s tions  
• Make one connection at a time and then monitor the incoming signal.  
If you hear a distinct hum or buzz, you may have a grounding  
problem with that particular device. See the section in this manual  
entitled “Grounding Techniques” (on page 26) for more information.  
• NEVER connect a microphone and line level input to the same  
channel simultaneously—use one or the other. You can have some  
channels connected to microphones and others to line level signals  
(for example, you might want to plug mics into channels 1 - 2 and  
line level signals into the remaining channels)—just don’t have both  
kinds of inputs connected to the same channel. The diagram below  
shows how your mic connectors should be wired:  
3 - SIGNAL  
1 GROUND  
2 + SIGNAL  
T
TO MIC  
• For easy control over a pair of matched signals (i.e. the left-right  
outputs of a stereo effects processor, keyboard, drum machine, tone  
generator, CD player, or tape recorder), use the MIXPAD’s stereo  
input channels. The Balance control in these channels will allow you  
to adjust the relative levels of the two inputs, and you can also  
equalize the stereo signal, with the same EQ settings applied to both  
inputs.  
• There are additional “hidden” (or at least not so obvious) stereo  
inputs to the MIXPAD; these are the Aux returns. Use these  
whenever you want to bring in a stereo signal that will not need to  
be equalized. Bear in mind that the two stereo Aux returns in the  
MIXPAD 12 / MIXPAD 9 can also be used as four monophonic  
returns and that the single stereo Aux return in the MIXPAD 4 can  
also be used as two monophonic returns (when connecting only  
one monophonic signal, use the “Aux Ret. 1/Mono” jack so that the  
returning signal is automatically panned dead center).  
20  
 
Conne cting the MIXPAD -  
Ge ne ral Sugge s tions  
• In the MIXPAD 12 and MIXPAD 9, when connecting only one  
monophonic signal to a stereo channel, always use the upper input.  
When only the upper input is connected in a stereo channel, the  
MIXPAD 12/9 treats that channel as if it is a mono channel and the  
signal can then be panned (using the Balance control). See the  
“Using Pan/Balance” and “Using Aux Sends And Returns” sections  
in this manual (pages 28 and 32) for more information.  
• In the MIXPAD 12 and MIXPAD 9, the Aux return jacks are  
unbalanced stereo inputs, with the tip carrying the left input signal  
and the ring carrying the right input signal (with the sleeve carrying  
common ground), as shown below (the MIXPAD 4 stereo channel  
line input is wired the same way). Insertion of a monophonic 1/4"  
jack into an Aux return will result in the incoming signal being  
automatically routed to the left input only (and therefore panned  
hard left).  
TIP (LEFT SIGNAL)  
RING (RIGHT SIGNAL)  
SLEEVE (COMMON GROUND)  
21  
 
Se tting Up and Us ing the  
MIXPAD  
Setting up your MIXPAD is a simple procedure which takes only a few  
minutes:  
1. Remove all packing materials (save them in case of need for future  
service) and decide where the unit is to be physically placed.  
2. Begin by connecting the MIXPAD main left/right outputs to a tape  
recorder or power amp (and the amp into loudspeakers). It is never  
a good idea to power up any amplifier that is not connected to  
loudspeakers.  
3. Next, make the signal input connections to the mic or line inputs of  
the various channels. WARNING: Because the MIXPAD 12 and  
MIXPAD 9 XLR mic connectors are always phantom powered (the  
MIXPAD 4 XLR mic connectors are powered only when the  
corresponding phantom power switch is pressed in), be sure to connect  
and disconnect microphones only with the MIXPAD powered off.  
Also, do not connect a channel’s line input if you already have  
something connected to its microphone input, or vice versa; each  
channel is designed to accept only one source or the other.  
4. Turn all channel Level and Trim controls as well as the Main Level  
control fully counterclockwise.  
5. If you running the MIXPAD off mains power, plug the included power  
supply into the rear panel AC connector and then into any standard AC  
socket. If you are running a MIXPAD 12 or MIXPAD 9 off battery power,  
plug the battery connector into the rear panel AC connector (for more  
information on operating the MIXPAD 12 / MIXPAD 9 off battery power,  
see Appendix A on page 34); if you are running a MIXPAD 4 off battery  
power, place two or three fresh 9 volt alkaline batteries in the rear panel  
battery compartment (three are required only if you need to apply  
phantom power to one or both mic inputs), being careful to observe the  
indicated polarity.  
6. Finally, press the Power switch in the main section to turn the  
MIXPAD on. In the MIXPAD 12 / MIXPAD 9, the “Power” LED will light  
steadily; in the MIXPAD 4, it will flash briefly to indicate good battery  
strength (the MIXPAD 4 “Power” LED lights steadily only when its  
batteries are weak and need replacing).  
22  
 
Se tting the Corre ct Gain  
Structure  
You’re now ready to establish the correct gain structure—the key to  
getting the best performance from the MIXPAD, or from any mixer, for  
that matter. This is a simple procedure that ensures optimum input and  
output levels so that no unnecessary noise (caused by too low a signal)  
or overload distortion (caused by too high a signal) is created. Here’s a  
step-by-step description of how to do so:  
a. With all connections made (as described above) but with the power  
amplifier and MIXPAD powered off, set the power amplifier volume to  
minimum. On the MIXPAD, turn all channel Trim and Level controls fully  
counterclockwise, and set the Main Level control to its “0” position.  
b. If you are using a MIXPAD 4 and either or both connected  
microphones require 18 volts phantom power, press in the corresponding  
phantom power switch.  
c. Set all channel equalizer and pan/balance knobs to their center  
detented “0” positions.  
d. Set all channel Aux send knobs and all Aux return level knobs fully  
counterclockwise.  
e. Turn on all devices connected to channel line inputs and Aux returns  
and set their level controls to unity gain or, if there is no unity gain indi-  
cated on their output control, to maximum. If you’ve got effects proces-  
sors connected to Aux returns, make sure they are sending completely  
“wet” (processed) signal, with no “dry” (unprocessed) signal mixed in.  
f. Press the MIXPAD Power switch in order to turn the unit on. Finally,  
turn on the power amplifier and set it to a moderate listening level.  
g. Play an instrument connected to one of the MIXPAD’s line inputs*  
and, while doing so, slowly raise the corresponding channel Level control  
to the 2 o’clock “0” position (for most line-level signals, the Trim control  
should remain fully counterclockwise). Listen for signs of any distortion.  
If you hear any, you may need to lower the output level of the instrument,  
though this will rarely occur. Conversely, if the signal is too low,  
something’s wrong: in all likelihood, the connecting audio cable is faulty.  
* If you’re using an instrument such as electric guitar or bass, we  
recommend that you connect it to the MIXPAD with a direct injection box  
to ensure correct impedance.  
23  
 
Se tting the Corre ct Gain  
Structure  
h. Once you’ve set the optimum level in step (g) above, continue  
playing the instrument and slowly raise the power amplifier volume until  
you reach the level you want to hear.  
i. Repeat step (g) above for each instrument connected to the  
MIXPAD channel line inputs.  
j. The procedure for setting optimum microphone levels is virtually  
identical; sing or speak into the mic at the level you expect to use in  
performance while slowly raising the Level control for that channel to its  
2 o’clock “0” position. Then carefully raise the Trim control for that  
channel until the main Left/Right peak LEDs in the main section just  
begin to light occasionally during the loudest signals. Again, listen  
carefully for any signs of audible distortion or unusually weak signal  
(indicating a likely fault in cabling).  
k. If you have any outboard signal processors connected to the Aux  
send and return jacks on the rear panel, follow this step. Because  
outboard effects processors can sometimes be quite noisy, it’s  
particularly important to maximize the amount of signal being sent to  
them via the MIXPAD Aux sends. The idea is to drive these devices as  
hot as possible (short of overloading them) and then to use the  
corresponding Aux return level to carefully adjust the amount of  
processed signal being blended with the dry signal. To set optimum  
Aux send levels, use a channel that has already had its gain structure  
adjusted in step (g) or (j) above. Turn the Aux send knob(s) for that  
channel to the “0” (unity gain) position and then play the instrument  
(or sing into the microphone) connected to that channel. Adjust the  
input levels of connected outboard effects processors so that their meter  
shows incoming signal normally in the 0 vu range (with only occasional  
higher excursions). Then it’s time to optimize the Aux return levels.  
While continuing to play your instrument (or continuing to sing into the  
microphone), slowly raise the Aux return level control(s) until you hear  
the desired amount of processed signal added to the dry signal.  
For more information, see the “Using the Aux Sends and Returns”  
section on page 32 in this manual.  
24  
 
Se tting the Corre ct Gain  
Structure  
l. The gain structure is now correctly set—you’ve optimized the level of  
all signals coming into and out of the MIXPAD, and the end result will be  
minimum noise and distortion and maximum clean sound. You’ll now  
find that the majority of your mixes can be accomplished with most  
channel Level controls at or near their 2 o’clock “0” (unity gain) position  
and that the main Left/Right peak LEDs rarely if ever light (remember, if  
they do light, it means that something is distorting!). If you need to make  
adjustments to the overall level, alter the level control of your power  
amplifier.  
If you encounter difficulty with any aspect of setting up or using your  
MIXPAD, you can call Samson Technical Support (1-800-372-6766)  
between 9 AM and 5 PM EST.  
25  
 
Grounding Te chnique s  
Hum and buzz are the biggest enemies you face when interconnecting  
a large number of different pieces of equipment to a central audio mixer.  
This is because each piece of equipment may operate at a marginally  
different voltage (this difference is called potential) and, when two  
devices at slightly different potential are physically connected with  
audio cabling, the end result can be nasty, extraneous noise (mind you,  
connecting two devices at very different potential can result in a major  
electrical shock!).  
However, there are several steps you can take to avoid grounding  
problems. First, assuming you have an isolated electrical circuit that  
can handle the electrical demands of your mixer and all connected  
audio equipment (these needs will usually be modest), you should  
always plug your mixer and all connected equipment into the same  
circuit. If possible, nothing else but this equipment should be connected  
to that circuit. If you can’t do this, at least avoid plugging your mixer and  
audio equipment into the same circuit that is already powering things  
like heavy machinery, air conditioners, heaters, refrigerators, washing  
machines, neon signs or fluorescent light fixtures. One particular culprit  
that will almost certainly create problems is the standard light dimmer  
(the kind that uses silicon controlled rectifiers). Where low-level lighting  
is desired, use incandescent fixtures with autotransformer-type dimmers  
(sometimes called Variacs) instead—these cost considerably more than  
the standard dimmer you’ll find at your local hardware store, but are well  
worth the extra expense.  
If you hear hum or buzz from a device that uses an external two-prong  
AC/DC adapter (such as the MIXPAD), you can try reversing the plug in  
the socket. If that doesn’t work, you may need to physically ground that  
device’s chassis by connecting a wire (called a strap) from it to a  
grounded piece of metal. Some pieces of equipment have a screw-type  
ground post to which the strap can be connected; if not, you can attach  
some kind of metallic binding post to the case itself. If you are using  
rack-mounted audio devices and are experiencing hum or buzz, there’s  
a simple test to determine the source of the problem: while keeping all  
devices powered on and connected with audio cabling, physically  
remove each device, one by one, from the rack. If the hum disappears  
when a particular device is removed, you’ll know that device is probably  
the culprit.  
26  
 
Grounding Te chnique s  
We also recommend that you use balanced audio cabling and  
connectors wherever possible. The MIXPAD provides electronically  
balanced inputs for mono line channel inputs and for its main outputs.  
The wiring diagram in the “Connecting The MIXPAD” section of this  
manual (on page 19) shows how 1/4" TRS (Tip/Ring/Sleeve) connectors  
should be wired for use with these inputs and outputs.  
In addition, you can minimize possible interference by planning your  
audio, electrical, and computer cable runs so that they are as far apart  
from one another as possible and so they don’t run parallel to one  
another. If they have to cross, try to ensure that they do so at a 90°  
angle (that is, perpendicular to one another). In particular, try to keep  
audio cabling away from external AC/DC adapters.  
Another, less common problem you may encounter is that of oscillation  
(a ringing tone), which, apart from being annoying, is potentially  
dangerous to your speakers. This is generally caused either by poor  
outside wiring or by returning a signal out of phase (most commonly from  
an outboard signal processor). If audible oscillation occurs, try isolating  
each input signal by turning down all other inputs. If one signal alone is  
causing the problem, you should be able to eliminate the oscillation by  
reversing that signal’s phase (many signal processors have a switch that  
allows you to do this).  
27  
 
Us ing Pan/ Balance  
The final Main output of the  
MIXPAD is stereo—that is, there  
are two discrete output jacks,  
labeled “left” and “right,” which  
will normally be routed to a  
O U T P U T  
B A L A N C E D  
+4 d B u  
L E F T  
R IG H T  
stereo power amplifier and two  
discrete speakers.* Because of  
this, you will usually be working  
with a stereo field that ranges from hard left to  
hard right. The Pan control in monophonic  
channels (and the Balance control in MIXPAD 12  
and MIXPAD 9 stereo channels, when only the  
upper input is connected) allows you to place  
each individual sound at any point within this  
left-right field, while keeping the overall level  
constant.  
L
R
P A N  
You can use stereo panning creatively in a variety  
of ways: For example, you might want to have  
guitars coming from one speaker and keyboards  
L
R
B A L A N C E  
from another, or you might use panning to “spread” the signal from a  
piano miked with two microphones—one over the bass notes (panned  
left) and the other over the treble notes (panned right). By turning a Pan  
knob while a signal is present, the sound appears to move in space (a  
process known as dynamic panning)—this can be particularly effective  
when applied to sound effects.  
In live performance, you may want to resist the temptation to pan  
anything completely hard left or right, since some members of the  
audience not seated in the center of the venue may miss some signal  
altogether. In these circumstances, you’re best to use modest panning,  
with signals routed no further than the 9 o’clock and 3 o’clock positions.  
* You can, of course, also use the MIXPAD monophonically—simply  
route the same signal to both the left and right outputs.  
28  
 
Us ing Pan/ Balance  
In the MIXPAD 4 stereo channel (channels 3/4) and in MIXPAD 12 and  
MIXPAD 9 stereo channels (channels 7/8, 9/10, and 11/12 in the  
MIXPAD 12; channels 4/5, 6/7, and 8/9 in the MIXPAD 9) where both  
inputs are connected, the upper input signal is automatically panned  
hard left and the lower input signal is automatically panned hard right.  
The Balance knob in these channels controls the relative levels of the  
two input signals. When the knob is placed at its center (detented)  
position, both the upper and lower inputs are at equal strength. When  
moved left of center, the signal of the upper channel remains the same  
but the signal of the lower channel is attenuated; when the knob is  
moved right of center, the reverse occurs: the signal of the lower channel  
remains the same but the signal of the upper channel is attenuated.  
When placed fully counter-clockwise, only the upper channel is heard;  
when placed fully clockwise, only the lower channel is heard.  
29  
 
Us ing Equalization  
One of the most exciting aspects of using a mixer  
O
such as the MIXPAD is the ability to shape a  
sound, using a process called equalization. But  
there are few areas of sound engineering more  
misunderstood than equalization, and, just as  
good EQ can really help a sound, bad EQ can  
really hurt it, so read on...  
-1  
5
+1 5  
H IG H  
O
-1  
5
+1 5  
Every naturally occurring sound consists of a  
broad range of pitches, or frequencies, combined  
together in a unique way. This blend is what  
gives every sound its distinctive tonal color.  
The EQ section in a mixer allows you to alter a  
sound by boosting or attenuating specific  
L O W  
MIXPAD 12/9 EQ  
O
frequency areas. The MIXPAD 12 and MIXPAD 9  
both provide independent two-band equalization  
controls for each of their input channels, while the  
MIXPAD 4 provides independent three-band  
equalization controls for each input channel.  
In all models, the EQ controls in stereo channels  
affect both input signals identically.  
-15  
+15  
HIGH  
O
-12  
+12  
MID  
O
Each EQ knob is labeled with the maximum  
amount of cut or boost provided (± 15 dB in the  
case of the High and Low frequencies, and, in  
the MIXPAD 4, ±12 dB in the case of the Mid  
frequency). In the MIXPAD 12 and MIXPAD 9, the  
-15  
+15  
LOW  
MIXPAD 4 EQ  
High EQ knob affects frequencies above 10 kHz, while the Low EQ  
knob affects frequencies below 100 Hz (with both using a shelving  
curve). In the MIXPAD 4, the High EQ knob affects frequencies above  
12 kHz, while the Low EQ knob affects frequencies below 80 Hz (with  
both again using a shelving curve). The MIXPAD 4 also provides an  
additional Mid EQ knob, affecting frequencies around 2.5 kHz (using a  
bell, or peaking curve). We provided these particular frequency areas  
because they have maximum impact on musical signals—that’s why  
they are sometimes known as “sweet spots.” When an EQ knob is in its  
center detented position (at “0”), it is having no effect. When it is moved  
right of center, the particular frequency area is being boosted; when it is  
moved left of center, the frequency area is being attenuated.  
30  
 
Us ing Equalization  
In most instances, the best way to approach equalization is to think in  
terms of which frequency areas you need to attenuate, as opposed to  
which ones you need to boost (boosting a frequency area also has the  
effect of boosting the overall signal; too much EQ boost can actually  
cause overload—with the accompanying Left/Right Peak LED warning!).  
Be aware of the phenomenon of masking, where loud sounds in one  
frequency range obscure softer sounds in the same range; by cutting EQ  
“notches” in a loud signal, you can actually make room for a softer one to  
shine through. And try not to think of EQ as a miracle worker—no  
amount of equalization can put a singer in tune or remove the distortion  
from an overloaded input signal! The key is to get the signal right in the  
first place, by using correct gain structure and mic placement.  
Although the specific EQ you will apply to a signal is very much a matter  
of personal taste, here are a few general suggestions: Boosting the low  
frequency of instruments such as bass drums or bass guitar will add  
warmth and make the sound “fatter”; conversely, you may want to  
attenuate the low frequency component of instruments such as cymbals,  
high-hats, and shakers so as to “thin” them out. Be careful not to boost  
high frequencies too much or you risk adding hiss to the signal, though  
just a touch can help add “shimmer” to an acoustic guitar, ride cymbal,  
or high-hat. If you are using a MIXPAD 4, you’ll find the mid-range EQ  
control to be particularly effective for vocals—attenuating it can give a  
vocal performance more of an “FM-radio” feel and boosting it can help a  
vocal cut through dense instrumentation. Finally, because the MIXPAD’s  
High and Low EQ controls both utilize shelving curves, attenuated High  
EQ settings can be used to reduce hiss (which is composed almost  
exclusively of high frequencies) and attenuated Low EQ settings can be  
used to reduce rumble (which is composed almost exclusively of low  
frequencies).  
31  
 
Us ing Aux Se nds and Re turns  
The purpose of Auxiliary sends are to allow you  
to combine the signal from multiple channels  
O
and send the resulting mix to external devices  
such as effects processors. The MIXPAD 12  
and MIXPAD 9 provide two such sends, while  
the MIXPAD 4 provides one.  
+1  
0
A U X 1  
P
R E  
O
When a channel’s Aux send knob is at its  
“0” position, the signal is routed with unity gain  
(that is, no boost or attenuation). As it is turned  
clockwise from the 0 position, the signal is  
boosted; as it is turned counterclockwise from  
+1  
0
2
A U X  
MIXPAD 12/9 Aux sends  
the 0 position, it is attenuated. In the MIXPAD 12 and MIXPAD 9, Aux  
send 1 is post-eq but pre-fader; that is, the level of the signal sent  
through this knob is determined by the EQ settings and (in mono  
channels) the position of the Trim control. It is, however, unaffected by  
the channel Level setting; for this reason, it is optimum for applications  
like headphone cueing or sending a feed to onstage monitors—both  
situations where you want the performer’s mix to be independent of the  
main mix. You can also use Aux 1 to route signal to a reverb processor  
in order to create a distancing kind of effect where the “wet” reverb  
signal remains constant even as the “dry” source signal fades away.  
In contrast, Aux send 2 is post-eq and post-fader; that is, the level of the  
signal is determined by EQ settings and the channel Level setting, as  
well as (in mono channels) the position of the Trim control. This is the  
condition of the single Aux send provided by the MIXPAD 4. Here, rais-  
ing or lowering the Level of the channel will affect the send level as well.  
The MIXPAD 12 and MIXPAD 9 also provide  
two stereo Aux returns (the MIXPAD 4  
provides one stereo Aux return). These allow  
O
you to return signal from outboard devices,  
either in stereo pairs or monophonically (many  
+1  
0
A U X R E T . 1 /2  
popular effects processors provide a single  
mono input but have two stereo outputs).  
You can think of the MIXPAD’s stereo Auxiliary  
returns as being somewhat similar to a stereo  
channel, except that a signal being brought into  
to a stereo channel can be equalized if  
O
+1  
0
A U X R E T .  
3
/4  
MIXPAD 12/9 Aux returns  
necessary and optionally sent on to other  
32  
 
Us ing Aux Se nds and Re turns  
outboard devices (via Aux sends). In  
A U X  
R E T U R N  
practice, you’ll probably want to use the  
1
/2  
Aux returns to bring in signal from  
connected effects processors. If the effects  
processors have stereo outputs, they  
should be connected to both the left and  
right Auxiliary return inputs so that their  
stereo integrity is retained. If they have  
mono outputs, you can route them to either  
the left or right inputs. In this way, you can  
actually connect up to four monophonic  
devices to the MIXPAD 12 or MIXPAD 9’s  
Aux return section (or two monophonic  
devices to the MIXPAD 4’s Aux return).  
Signal arriving at the left input is  
A U X  
R E T U R N  
3
/4  
MIXPAD 12/9 Aux return jacks  
AUX RET 1/MONO  
automatically panned hard left and signal  
arriving at the right input is automatically  
panned hard right.  
AUX RET 2  
In the MIXPAD 12 and MIXPAD 9, the Aux  
return jacks are unbalanced stereo inputs,  
with the tip carrying the left input signal and  
the ring carrying the right input signal (the  
sleeve carries common ground), as shown in  
the wiring diagram on page 21 of this  
MIXPAD 4 Aux return jacks  
manual. Insertion of a monophonic 1/4"  
jack into an Aux return will result in the  
incoming signal being automatically routed to the left input only (and  
therefore panned hard left). The MIXPAD 4 provides independent  
unbalanced 1/4" inputs for each Aux return “side.” When connecting  
only a single mono signal to the MIXPAD 4 Aux Return, use the  
“Aux Ret. 1/Mono” input; the signal will then be automatically panned  
dead center. When connecting stereo signals, use both jacks; the signal  
connected to the “Aux Ret. 1/Mono” jack will be automatically panned  
hard left and the signal connected to the “Aux Ret 2” jack will be  
automatically panned hard right.  
33  
 
Appe ndix A: Ope rating the  
MIXPAD 12/ 9 off Batte ry Powe r  
The MIXPAD 12 and MIXPAD 9 can optionally be battery powered.  
This requires the use of two 12 Volt rechargeable Lead-Acid (Gelcell)  
batteries, connected to the rear panel AC connector, wired as shown in  
the illustration below. These batteries will provide the necessary bi-polar  
voltages needed to operate and maintain excellent audio quality.  
1 m  
1 piece  
20cm  
Phant om Power  
+12V  
M9/M12 Connect or  
St andard 5 Pin DIN (MIDI) Connect or  
-12V  
Ground  
Male  
Male  
Ground  
"T" Connect or  
(2 pieces)  
All Quick Disconnect s are Female except  
where not ed. All Male and Female Quick  
Disconnect s are fully insulat ed and .187"  
20cm  
Female .187" Quick Disconnect  
Male .187" Quick Disconnect  
Jumper  
(2 pieces)  
Rear View of Connect or for soldering  
Pin 1 = +15V  
Pin 2 = Ground  
Pin 3 = Ground  
Pin 4 = -15V  
1
3
45º  
4
5
2
Pin 5 = Phant om Power  
-12V  
Ground  
Ground  
+12V  
Phant om Power  
"T" Connect or  
Jumper  
All Bat t eries .187" Male Quick Disconnect  
34  
 
Appe ndix A: Ope rating the  
MIXPAD 12/ 9 off Batte ry Powe r  
The current draw of the two models (without phantom power) are:  
MIXPAD9:  
MIXPAD12:  
125mA (.125A)  
160mA (.160A)  
Typical usage times for the two models:  
MIXPAD9  
MIXPAD12  
10 hours  
8 hours  
If you are using dynamic microphones, no phantom power is necessary.  
To power a condenser microphone, we recommend the use of one  
additional 12 Volt rechargeable battery. (Note: Batteries come with  
many connector options. We recommend the type with .187" quick  
disconnects for ease of connection.) Optional battery connect kits for  
both the MIXPAD9 and MIXPAD12 are also available; contact your local  
authorized Samson Audio dealer for more information.  
Recommended batteries:  
PowerSonic  
Eagle Picher  
Panasonic  
Yuasa  
PS-1212  
CF12V1.5  
LCR12V1.3P  
NP1.2-12  
MX12012  
Union  
Batteries and rechargers are available through the following national  
electronic parts distributors:  
For PowerSonic and Eagle-Picher Batteries and accessories:  
MOUSER Electronics (800-346-6873)  
RS Electronics (800-555-5312) (PowerSonic only)  
For Panasonic batteries and accessories:  
Digi-Key (800-344-4539)  
For Yuasa batteries and accessories:  
Newark Electronics (800-367-3573)  
For Union batteries and accessories:  
Plainview Batteries (516-249-2873)  
If you require any assistance regarding use and/or purchase of  
batteries, please feel free to contact the Samson Technologies  
Customer Service Dept. at 516-364-2244 between 9AM and 5PM EST.  
35  
 
MIXPAD 12 / 9 Spe cifications  
Normal  
Frequency Response (Trim @ Min, unity gain ± 3 dB)  
Limit  
Mic to Main  
Line to Main  
Aux Return to Main  
Line to Aux Send 1/2  
5 Hz - 65 kHz  
5 Hz - 65 kHz  
5 Hz - 75 kHz  
5 Hz - 75 kHz  
10 Hz - 50 kHz  
T.H.D. (Trim @ Min, +4dBu output, unity gain, 1 kHz w/30 Hz LPF)  
Mic/Line to Main (Mono Ch)  
Line to Main (Stereo Ch)  
Line to Aux Send  
0.002%  
0.002%  
0.002%  
0.01%  
0.01%  
0.01%  
Equivalent Input Noise (“A” filter on, input shorted)  
Mic  
Line  
-128 dB  
-111 dB  
-128 dB  
-111 dB  
Maximum Voltage Gain  
Mic to Main  
Line to Main (Mono Ch)  
74 dB  
54 dB  
34 dB  
20 dB  
64 dB  
74 dB  
24 dB  
34 dB  
Line/Tape to Main (Stereo Ch)  
Aux Return to Main  
Mic to Aux Send 1 (Mono Ch)  
Mic to Aux Send 2 (Mono Ch)  
Line to Aux Send 1 (Stereo Ch)  
Line to Aux Send 2 (Stereo Ch)  
Residual Noise (30 kHz LPF, all control Min)  
L/R Main  
Aux Send 1/2  
100 dB  
92 dB/91 dB  
95 dB  
85 dB  
Crosstalk (@ 1 kHz w/ 30 kHz LPF)  
Ch vs. Ch  
77 dB  
82 dB  
70 dB  
75 dB  
Input vs. Output  
Peak LED Sensitivity (before clipping)  
Headphone output (600 ohm load)  
3 dB  
3 ± 2dB  
100 mW  
112 mW  
Maximum Input Level (1 kHz, ± 3dB)  
Mic Input (Mono Ch)  
+22 dBu  
+7 dBu  
Line Input (Stereo Ch)  
Input Channel Equalizer (± 2dB)  
High (shelving)  
10 kHz ±15 dB  
100 Hz ±15 dB  
Low (shelving)  
Dimensions (W x D x H)  
MIXPAD 9: 239 x 228 x 58 mm  
(9.4 x 9 x 2.3 in.)  
MIXPAD 12: 324 x 228 x 58 mm  
(12.75 x 9 x 2.3 in.)  
36  
 
MIXPAD 4 Spe cifications  
Normal  
Frequency Response (Trim @ Min, unity gain ± 3 dB)  
Limit  
Mic to Main  
Line to Main  
Aux Return to Main  
Line to Aux Send  
5 Hz - 54 kHz  
5 Hz - 54 kHz  
5 Hz - 98 kHz  
5 Hz - 57 kHz  
10 Hz - 50 kHz  
T.H.D. (Trim @ Min, +4dBu output, unity gain, 1 kHz w/30 Hz LPF)  
Mic/Line to Main (Mono Ch)  
Line to Main (Stereo Ch)  
Line to Aux Send  
0.02%  
0.02%  
0.02%  
0.05%  
0.05%  
0.05%  
Equivalent Input Noise (“A” filter on, input shorted)  
Mic  
-128 dB  
-128 dB  
Line  
-104 dB  
Maximum Voltage Gain  
Mic to Main  
Line to Main (Mono Ch)  
Line/Tape to Main (Stereo Ch)  
Aux Return to Main  
Mic to Aux Send  
74 dB  
56 dB  
34 dB  
20 dB  
74 dB  
34 dB  
Line to Aux Send (Stereo Ch)  
Residual Noise (30 kHz LPF, all control Min)  
Main  
Aux Send  
-89 dBu  
-86 dBu  
-85 dBu  
-82 dBu  
Crosstalk (@ 1 kHz w/ 30 kHz LPF)  
Ch vs. Ch  
75 dB  
87.5 dB  
70 dB  
80 dB  
Input vs. Output  
Peak LED Sensitivity (before clipping)  
Headphone output (600 ohm load)  
5 dB  
5 ± 2dB  
30 mW  
38 mW  
Maximum Input Level (1 kHz, ± 3dB)  
Mic Input (Mono Ch)  
10.5 dBu  
7.6 dBu  
Line Input (Stereo Ch)  
Input Channel Equalizer (± 2dB)  
High (shelving)  
12 kHz ±15 dB  
2.5 kHz ± 12 dB  
80 Hz ±15 dB  
Mid (peaking)  
Low (shelving)  
Dimensions (W x D x H)  
163 x 228 x 69 mm  
(6.4 x 9 x 2.7 in.)  
Weight  
900 g. • 2 lbs.  
37  
 
Note s  
 

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