Samson TM300 User manual

®
OWNERS MANUAL
POWERED
MIXER
TM300

Produced by On The Right Wavelength for Samson Technologies Corp.
Copyright 1999, Samson Technologies Corp.
Printed April 1999
Samson Technologies Corp.
575 Underhill Blvd.
P.O. Box 9031
Syosset, NY 11791-9031
Phone: 1-800-3-SAMSON (1-800-372-6766)
Fax: [phone]
Table of Contents
ENGLISH
Introduction 3
TM300 Features 3
Guided Tour 5
Overview 5
Channels 6
Main Section 8
Rear Panel 11
Connecting the TM300 12
TM300 Interconnections - Stereo Configuration 13
TM300 Interconnections - Split Mono Configuration 14
Setting Up and Using the TM300 15
Setting the Correct Gain Structure 16
Grounding Techniques 18
Using Equalization 19
Using Pan 21
Using Aux Sends and Returns 22
Using Inserts 23
Using the Internal Effects Processor (DSP) 24
Specifications 58
FRANÇAIS
Introduction 25
Caractéristiques Techniques du TM300 25
Visite guidée 27
Les voies 27
Section principale 29
Face arrière 32
Installation et utilisation du TM300 33
Réglages de gain 34
Spécifications 58
DEUTSCHE
Einleitung 36
TM300 Merkmale 36
Übersicht 38die Kanäle 38
Hauptabschnitt 40
Rückseite 43
Einstellung und Bedienung des TM300 44
Einstellung der Gain-Struktur 45
Technische Daten 58
ESPAÑOL
Introducción 47
Características de la TM300 47
Recorrido guiado 49
Canales 49
Sección principal 51
Panel trasero 54
Ajuste y uso de la TM300 55
Ajuste de la estructura de ganancia correcta 56
Especificaciones 58

Introduction / TM300 Features
We know you don’t like reading owners manuals, but you’ve just purchased one of the
finest powered mixers around, and we want to tell you about it! So, before you plug in
and start making music, we’d like to suggest you take just a few moments out to scan
these pages. We’ll make it as painless as possible, we promise—and, who knows, you
might just pick up a tip or two.
The Samson TM300 is a practical, full-featured 6-channel stereo powered mixer—
complete with built-in signal processing—all in a compact tabletop design. It’s ideal for
use in rehearsal studios, small club venues, lounges and other sound reinforcement
applications—in fact, it can be used wherever there are a number of microphone or
line-level sources that need to be mixed down to a stereo output. Simply hook it up to a
set of PA speakers and you’re ready to go!
In these pages, you’ll find an overview of TM300 features, followed by a guided tour of
its front and rear panels. Then we’ll describe how the TM300 should be connected to
your existing equipment (including a wiring diagram) and talk about the important topics
of gain structure and grounding techniques. Next, we’ll cover a number of specific
TM300 features (such as panning, equalization, auxiliary sends and returns, inserts and
using the onboard effects) 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 other Samson products in the future. Also, be sure to check out our
website (http://www.samsontech.com) for complete information about our full product
line.
SPECIAL NOTE: Should your TM300 ever require servicing, a Return Authorization
number (RA) 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 TM300 in its
original carton and packing materials.
TM300 Features
The compact design of the TM300 belies its extraordinary versatility and excellent sound
quality. Here are some of its main features:
•Six independent channels, each with mic and line inputs. These allow you to blend
together a variety of source signals, including dynamic or condenser microphones,
keyboards, CD/tape players, etc. Standard XLR mic connectors (for microphone
inputs) and electronically balanced 1/4" jacks (for line-level inputs) are provided for
each channel. In addition, there is a dedicated stereo Tape input that provides dual
phono (RCA) jacks.
•Flexible switching allows the TM300 to be used either in standard stereo
configuration or in a unique “split mono”mode, where it can drive both main PA
speakers and onstage monitors simultaneously.
•Built-in stereo power amplifier delivers 150 watts per side into 4 ohms. Any standard
speaker cabinets (four, eight, or sixteen ohms) can be connected to the four
rear-panel 1/4" speaker output jacks.
•Power amp utilizes a variable-speed fan and bipolar design for maximum reliability
and long life.
•Onboard digital signal processor (DSP) with three high-quality effects.
3
ENGLISH

TM300 Features
•Phantom power switch enables you to use the TM300 with high-quality condenser
microphones. When turned on, 48 volts of phantom power is provided to the mic
connectors of all channels.
•Two Aux sends per channel (one pre-fader and the other post-fader) allow you to
route multiple signals to the internal DSP or to external signal processors.
•Dual stereo aux returns—with dedicated front-panel level controls—give you the
ability to blend in the return signal from the internal DSP and/or external signal
processors or other line-level devices without having to utilize input channels.
•Extensive equalization includes independent 3-band eq for each channel, with 15 dB
of cut or boost for low (100 Hz) and high (10 kHz) frequencies, and 12 dB of cut or
boost for the mid (1.8 kHz) frequency. In addition, a dual seven-band graphic master
equalizer allows you to “tune”the output of the TM300 to the particular room
environment you are in—particularly useful for eliminating ringing or feedback
problems. This graphic equalizer can be used in stereo or can be “split”so that one
side affects the main PA and the other side affects stage monitors.
•Constant level Pan controls for each channel that allow you to precisely place each
input signal in the left-right plane.
•Center detents for all Pan and EQ controls, making it easy to use the TM300 even in
low-light live performance situations.
•Continuously adjustable wide-range input Trim controls for each channel allow you
to precisely set the correct input and output gain structure.
•Independent 65 mm faders for each channel and for the stereo bus.
•Pre Fader Listen (PFL) soloing for each channel, allowing headphone monitoring of
individual channels, pre-fader (but post-EQ) without affecting the signal being output
either by the speaker or various line-level outputs.
•Front panel metering system includes a ten-segment level meter and allows you to
view at a glance the continuous levels of the main stereo output and/or Aux sends.
•Peak LEDs for each channel show you at a glance when an input signal is on the
verge of overloading.
•Dedicated status LEDs show main power and phantom power on/off.
•Separate Record out jacks (with dedicated level control) allow you to directly connect
the TM300 to any tape recorder. In addition, a handy Mono output jack provides a
line-level signal for connection to external monitor power amplifiers.
•An independent front-panel headphone output with dedicated volume control for
private monitoring of the main stereo output, Aux sends, or soloed channels.
•Main inserts and four channel inserts allow you to use outboard signal processors
such as equalizers, compressor/ limiters, or noise gates in a standard “effect loop.”
•Last but certainly not least, affordability. The TM300 has been designed from the
ground up to provide versatility and excellent sound quality at a cost-conscious price.
4
ENGLISH

Guided Tour - Overview
The following illustration shows an overview of the front panel of the TM300:
5
INSERT
LINE
MIC
1
INSERT
LINE
MIC
2
INSERT
LINE
MIC
3
INSERT
LINE
MIC
4
MIC
5
MIC
6
123456 L–STEREO– R
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TRIM
–6 –50
+14 –30
TRIM
–6 –50
+14 –30
TRIM
–6 –50
+14 –30
TRIM
–6 –50
+14 –30
TRIM
–6 –50
+14 –30
TRIM
–6 –50
+14 –30
PEAK PEAK PEAK PEAK PEAK PEAK
HIGH
–15 +15
0
MID
–12 +12
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LOW
–15 +15
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LOW
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LOW
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LOW
–15 +15
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MID
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MID
–12 +12
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MID
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MID
–12 +12
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MID
–12 +12
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HIGH
–15 +15
0
HIGH
–15 +15
0
HIGH
–15 +15
0
HIGH
–15 +15
0
HIGH
–15 +15
0
AUX 1 PRE
+10
AUX 2
+10
00
0
00
0
00
0
0
0
0
0
0 0
L R
PAN
AUX 1 PRE
+10
AUX 2
+10
L R
PAN
AUX 1 PRE
+10
AUX 2
+10
L R
PAN
AUX 1 PRE
+10
AUX 2
+10
L R
PAN
AUX 1 PRE
+10
AUX 2
+10
L R
PAN
AUX 1 PRE
+10
0
LEVEL
HEADPHONE
+10
0
REV TO AUX 1
+10
0
AUX SEND 1
+10
0
AUX RET 1
+10
0
TAPE IN
VOCAL
L HALL
S HALL
ON
METER HEADPHONE
SOURCE
AUX 1 / 2
RIGHTLEFT
L / R
PHANTOM
+10
0
AUX SEND 2
+10
0
AUX RET2/REV
+10
REC OUT
+4
L R
PAN
+12dB
0dB
-12dB
6.4KHz2.5KHz1KHz400Hz160Hz63Hz 15KHz
+12dB
0dB
L
R
-12dB
6.4KHz2.5KHz1KHz400Hz160Hz63Hz 15KHz
RIGHT
AUX2
+2
+4
0
–2
–4
–9
–12
–15
–20
–25
ON
OFF
EQ ON/OFFAUX 1/MONITOR
6 CHANNEL 150 WATT STEREO MIXER
REC OUT
+4dBu
TAPE IN
–10dB
LR LR
AUX SEND 1
MONO OUT+4dB
AUX SEND 2
+4dB
R
L
L/MONO
AUX RET1
+4dB
AUX RET 2 POST EQ
INSERT
R
DSP
SAMSON
AUX 2
+10
PFL
PFL PFL PFL PFL PFL
LINE LINE MAIN
6.4KHz2.5KHz1KHz400Hz160Hz63Hz 15KHz
+2
+4
0
–2
–4
–9
–12
–15
–20
–25
LEFT
AUX1 POWER
Channels Main Section
40
0
OO
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ENGLISH

Guided Tour - Channels
1: Mic inputs - Use these electronically balanced XLR jacks to connect microphones to
the TM300. 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 (see #5 below) is turned down. WARNING: Do not connect a
channel’s microphone input if you already have something connected to its line input (see
#2 below); all channels are designed to accept only one source or the other.
2: Line inputs - Use these electronically balanced 1/4" jacks to connect line-level sources
such as synthesizers, drum machines, CD players, tape decks, or effects processors to
any of the TM300’s channels. We recommend the use of 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). The “Connecting the TM300”section on
page 10 in this manual provides more information on how best to use channel inputs.
WARNING: Do not connect a channel’s line input if you already have something connected
to its microphone input (see #1 above); all channels are designed to accept only one
source or the other.
3: Channel Inserts - Provided in channels 1 - 4 only. Use these to insert an external
effects processor (such as outboard equalizer, compressor/limiter or noise gate) in an
“effects loop”configuration. These jacks accept 1/4" TRS plugs, with the ring carrying the
send signal and the tip carrying the return signal. Normally, this will be connected to a
Y-cord; see the “Connecting The TM300”section on page 10 in this manual for more
information and a wiring diagram.
4: Peak LED - This warning light indicates an overload situation. It lights whenever a
channel’s signal is 3 dB short of clipping. To stop it from lighting (and to eliminate the
accompanying sonic distortion), turn down the channel’s input Trim (see #5 below) or
reduce the amount of equalization boost (see #6 below).
5: Trim - Determines the input level of the connected signal. This knob is continuously
adjustable from +14 dB to -30 dB (in the case of line-level inputs) or from -6 to -50 dB (in
the case of mic-level inputs). The input signal is boosted when the Trim control is turned
clockwise and is lowered (attenuated) when turned counterclockwise. For information on
how to properly set this for each channel, see the section on page 14 entitled “Setting The
Correct Gain Structure.”
6: Equalizer - These knobs determine the amount of boost or attenuation in each
frequency band (up to 15 dB for low and high frequencies, and up to 12 dB for the mid
frequency). The mid frequency control (centered at 1.8 kHz) utilizes a resonant (“bell”)
peaking curve, while the high and low frequency controls (centered at 10 kHz and 100 Hz,
respectively) utilize shelving curves. 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 17 in this manual.
7: Auxiliary sends - These knobs allow you to route signal to either or both of the
TM300’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
the internal DSP or 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 pre-eq and pre-fader; that is, the level of the signal
is determined solely by its Trim control (see #5 on the previous page). In contrast, Aux
6
1
1
2
3
4
5
7
6
8
9
10
INSERT
LINE
MIC
1
0
L
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M
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TRIM
–6 –50
+14 –30
PEAK
HIGH
–15 +15
0
MID
–12 +12
0
LOW
–15 +15
0
AUX 1 PRE
+10
AUX 2
+10
0
0
00
L R
PAN
PFL
40
0
OO
OO
35
30
25
20
15
10
ENGLISH

Guided Tour - Channels
send 2 is post-eq and post-fader; that is, the level of the signal is determined by
the channel’s Trim control, its EQ settings, and the position of its fader. Aux
send 2 is used for routing signal to the TM300’s internal DSP For more
information, see the “Using Aux Sends and Returns”and “Using the DSP”
sections on pages 20 and 22 in this manual.
8: Pan - 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 the
left and right speaker 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. For more information, see the “Using
Pan”section on page 19 in this manual.
9: PFL (“Pre Fader Listen”) switch - When pressed in, the channel is soloed
in connected headphones (see #24 on page 8). Soloing is non-destructive; that
is, it has no effect on the main stereo output.
10: Channel Fader - This linear slider determines the signal level being sent to
the main output as well as affecting the signal level being routed to Aux send 2
(which is post-fader; Aux 1 is always pre-fader). In practice, you will use the
channel faders to continuously adjust the levels of the various signals being
blended together by the TM300. The “0”position of the fader indicates unity
gain (no level attenuation or boost). Moving the fader down from the “0”position
(towards “∞”) causes the signal to be attenuated (at the very bottom, it is
attenuated infinitely—in other words, there is no sound).
For best signal-to-noise ratio, all faders for channels carrying signal should
generally be kept at or near their “0”position. Channels that are unused should
have their faders kept all the way down at their “∞”(minimum) level. See the
“Setting the Correct Gain Structure”section on page 14 in this manual for more
information.
7
ENGLISH

8
Guided Tour - Main Section
1: Tape input (L, R) - Connect the outputs of a
tape or CD player to this set of dual phono jacks.
The volume of the incoming signal is controlled
by the Tape In level control (see #7 on the next
page).
2: Aux Returns (1, 2) - Connect signal from
external stereo devices such as effects proces-
sors to these unbalanced 1/4" jacks. See the
“Connecting the TM300”section on page 10 and
the “Using Aux Sends and Returns”section on
page 20 in this manual for more information.
3: Record outputs (L, R) - This set of dual
phono jacks allow you to connect the output of
the TM300 to the inputs of a two-track recorder.
The volume of the incoming signal is controlled
by the Record Out level control (see #8 on the
next page). See the “Connecting the TM300”
section on page 10 in this manual for more
information.
4: Main Inserts (L, R) - Use these to insert an
external effects processor (such as outboard
equalizer, compressor/limiter or noise gate)
across the TM300’s main stereo output in an
“effects loop”configuration. This enables you to
process the entire mix simultaneously at unity
gain. The “Post EQ”pair of Main Inserts is
affected by both the seven-band graphic master
equalizer and stereo faders, while the “Pre EQ”
pair is not. These jacks accept 1/4" TRS plugs,
with the ring carrying the send signal and the tip
carrying the return signal. Normally, this will be
connected to a Y-cord; see the “Connecting The
TM300”section on page 10 in this manual for
more information and a wiring diagram. The Main
Inserts can also be used to link multiple TM300s
or to bring the output from another mixer into the
TM300 without taking up channel line inputs.
See the “Using Inserts”section on page 21 in
this manual for more information.
5: Mono Out - This unbalanced 1/4" jack pro-
vides a monophonic line-level output, unaffected
by the Stereo faders (see #22 on page 8). It can
be used to connect the TM300 to an external
monitor mixer/amplifier/speaker system so that
performers can receive an onstage monitor mix.
See the “Connecting the TM300”section on page
10 in this manual for more information.
6: Aux Sends (1, 2) - These unbalanced 1/4" jacks allow you to route signal from either
of the TM300’s two discrete Aux Sends to external devices such as effects processors.
Aux send1 is pre-fader, while Aux Send 2 is post-fader. See the “Using Aux Sends and
Returns”section on page 20 in this manual for more information.
L–STEREO–R
0
LEVEL
HEADPHONE
+10
0
REV TO AUX 1
+10
0
AUX SEND 1
+10
0
AUX RET 1
+10
0
TAPE IN
VOCAL
L HALL
S HALL
ON
METER HEADPHONE
SOURCE
AUX 1/2
RIGHTLEFT
L/R
PHANTOM
+10
0
AUX SEND 2
+10
0
AUX RET2/REV
+10
REC OUT
+4
+12dB
0dB
-12dB
6.4KHz2.5KHz1KHz400Hz160Hz63Hz 15KHz
+12dB
0dB
L
R
-12dB
6.4KHz2.5KHz1KHz400Hz160Hz63Hz 15KHz
RIGHT
AUX2
ON
OFF
EQ ON/OFFAUX 1/MONITOR
6 CHANNEL 150 WATT STEREO MIXER
REC OUT
+4dB
TAPE IN
–10dB
LR LR
AUX SEND 1
MONO OUT+4dB
AUX SEND 2
+4dB
RL
L/MONO
AUX RET1
AUX RET 2 POST EQ
INSERT
R
DSP
SAMSON
1
2
7
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POWER
6.4KHz2.5KHz1KHz400Hz160Hz63Hz 15KHz
MAIN
+4dB
LEFT
AUX1
+4
+2
0
-2
-4
-9
-12
-20
-25
-15
+4
+2
0
-2
-4
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-12
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-25
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8
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ENGLISH

9
Guided Tour - Main Section
7: Tape In Level - Controls the level of signal arriving at the Tape Input jacks (see #1 on the preceding page).
8: Record Out Level - Controls the level of signal being output by the Record Out jacks (see #3 on the preceding page).
9: Auxiliary Return Level (1,2) - These knobs determine the input level of signal arriving via the TM300’s two stereo
Auxiliary return jacks (see #2 on the previous page). The “0”(2 o’clock) position of each knob indicates unity gain
(no level attenuation or boost). Moving each knob counterclockwise from the “0”position (towards “∞”) causes the signal
to be attenuated (at the fully counterclockwise position, it is attenuated infinitely—in other words, there is no sound).
Moving each knob clockwise from the “0”position (towards “+10”) causes the signal to be boosted by as much as 10 dB.
Note that, when the DSP On/Off switch (see #19 on the next page) is pressed in, the internal DSP signal is instead
routed to Aux Return 2, with the Aux Return Level 2 knob controlling the amount of “wet,”processed signal. For
information on how to properly set these, see the sections in this manual entitled “Setting the Correct Gain Structure,”
“Using the Aux Sends and Returns”and “Using DSP”(pages 14, 20 and 22).
10: Auxiliary Send Level (1,2) - These knobs determine the output level of signal being routed to the TM300’s two
stereo Auxiliary Send jacks (see #6 on the preceding page) and, in the case of Aux Send 2, to the internal DSP (see the
“Using DSP”section on page 22 in this manual). The “0”(2 o’clock) position of each knob indicates unity gain (no level
attenuation or boost). Moving each knob counterclockwise from the “0”position (towards “∞”) causes the send signal to
be attenuated (at the fully counterclockwise position, it is attenuated infinitely—in other words, there is no signal being
sent). Moving each knob clockwise from the “0”position (towards “+10”) causes the send signal to be boosted by as
much as 10 dB. 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 14 and 20).
11: Meter - This ten-segment bar meter shows either the Left/Right output level or the Aux 1/2 Send level, depending
upon the setting of the Meter Headphone Source switch (see #15 below). For optimum signal-to-noise ratio, try to adjust
all left/right and Aux send levels so that program material is usually at or around 0 dB, with occasional but not steady
excursions to the red “+”segments. For more information, see the sections in this manual entitled “Setting the Correct
Gain Structure”and “Using the Aux Sends and Returns”(pages 14 and 20).
12: Power LED - Lights steadily green whenever the TM300 is powered on.
13: Phantom LED - Lights steadily red when the Phantom Power switch (see #14 below) is engaged.
14: Phantom Power switch - When this switch is pressed in, the TM300 delivers 48 volts of phantom power to pins
2 and 3 of all XLR microphone connectors in all channels. WARNING: Only use this switch with the TM300 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 TM300.
Refer to the owners manual of your microphone to determine whether or not it requires 48 volts phantom
power—we cannot assume responsibility if you damage a mic by incorrectly applying phantom power. If you’re
not completely certain that one or more connected mics require 48 volts phantom power, leave this switch off (its out
position).
15: Meter / Headphone Source switch - When out (the “up”position), the Left/Right stereo output signal is routed to
the headphones jack (see #24 on the next page) and to the ten-segment meter (see #11 on the previous page).
When pressed in, the Aux send 1 and 2 output signals are routed to the headphones jack and to the ten-segment meter.
Note that, whenever any channel PFL switches are depressed (see #9 on page 5), the soloed channel(s) are instead
routed to the headphones jack (though not to the meter).
16: Rev To Aux 1 Level - This knob determines the level of signal being routed from the internal DSP to Aux Send 1.
It allows you to add reverb or other signal processing to the sound in onstage monitors or headphones connected to the
TM300 Aux Send 1 jack (when operating the TM300 in standard stereo configuration) or the right speaker outputs (when
operating the TM300 in “split mono”configuration; that is, when the Aux 1 / Monitor switch [see #19 on the next page] is
pressed in). For more information, refer to the wiring interconnection diagrams on pages 11 and 12 and to the sections
in this manual entitled “Using the Aux Sends and Returns”and “Using DSP”on pages 20 and 22.
ENGLISH

Guided Tour - Main Section
17: DSP select switches - Allows you to select any of three preset reverb effects for the onboard DSP: Vocal, Long Hall
(“L HALL”) or Short Hall (“S HALL”). For more information, see the “Using DSP”section on page 22 of this manual.
18: DSP On/Off switch - When pressed in (“On”), output signal from the internal DSP is routed to Aux Return 2. When
up (“Off”), Aux Return 2 instead receives signal from any device connected to the Aux Return 2 jacks. For more
information, see the “Using the Aux Sends and Returns”and “Using DSP”sections on pages 20 and 22 in this manual.
19: Aux 1 / Monitor switch - When pressed in, Aux send 1 is routed to the right side of the TM300’s power amplifier and
the stereo mix is automatically combined to mono and routed to the left side of the TM300’s power amplifier. This allows
the TM300 to be used in a “split mono”configuration, so that it can drive both main “Front Of House”PA speakers (from
the left speaker output ) and onstage monitors (from the right speaker output) without the need for any external power
amplifier. When used in a “split mono”configuration, the Rev To Aux 1 Level knob allows you to route signal from the
internal DSP to your onstage monitors (the signal can also be routed to Aux Return 2 for simultaneous use in the main PA
signal. For more information, see the “Using the Aux Sends and Returns”and “Using DSP”sections on pages 20 and 22
in this manual.
20: EQ On/ Off switches (L, R)- When pressed in (“On”), the equivalent side of the master seven-band graphic
equalizer is active; when out (“Off”), the equivalent side of the master seven-band graphic equalizer is inactive regardless
of the settings of the EQ sliders (see #21 below). Note that, when using the TM300 in a “split mono”configuration (that is,
when the Aux 1 / Monitor switch [see #19 above] is pressed in), the left side of the graphic equalizer affects the main
“Front Of House”PA speakers and the right side affects the onstage monitors, saving you the expense of having to use a
separate outboard graphic equalizer for your onstage monitors.
21: Graphic EQ sliders - These sliders allow you to add 12 dB of boost or attenuation to seven different frequency
areas. When a slider is at its center detented (“0 dB”) position, the selected frequency area is unaffected (it is said to be
flat). When a slider is moved up (above the “0 dB”position, towards the “+12 dB”position), the selected frequency area
is boosted, and when it is moved down (below the “0 dB”position, towards the “-12 dB”position), the selected frequency
area is attenuated. For more information, see the “Using Equalization”section on page 17 in this manual.
22: Stereo Faders - These linear sliders determine the relative level of the main left/right stereo outputs. The “0”
position of each fader indicates unity gain (no level boost or attenuation). Moving each fader below this position (towards
the “∞”position) causes the signal to be attenuated (at the very bottom, it is attenuated infinitely—in other words, there is
no sound). For best signal-to-noise ratio, both Stereo faders should generally be kept at or near the 0 level. For more
information, see the “Setting The Correct Gain Structure”section on page 14 in this manual.
23: Headphone Level - This knob sets the level of the signal sent to the headphone jack (see #24 below).
WARNING: To avoid possible damage to connected headphones (or, worse yet, to your ears!), always turn this all the
way off (to the fully counterclockwise “0”position) before plugging in a pair of headphones—then raise the level slowly
while listening. The Headphone Level has no effect on any other TM300 outputs.
24: Headphone jack - Connect any standard stereo headphones to this jack (via a 1/4" TRS plug) for private monitoring
of the stereo output, Aux sends, or soloed channels (depending upon the setting of the Meter Headphone Source switch
[see #15 on the preceding page] and whether or not any channel PFL switches have been pressed in). The built-in
TM300 headphone preamp delivers approximately 100 mw of power.
10
ENGLISH

Guided Tour - Rear Panel
1: Vent - To ensure proper cooling of the TM300 power amplifier, make sure this vent is
unobstructed at all times.
2: Fuse holder - Holds an 8 A / 250 V fuse for 115 volt operation or a 4 A / 250 V fuse
for 230 volt operation
3: AC input - Connect the supplied heavy gauge 3-pin “IEC”power cable here.
4: Speaker Outputs - These are the TM300’s main outputs; use these four unbalanced
jacks (two of which carry the left signal and two of which carry the right) to connect the
TM300 to loudspeakers rated at 4 ohms or greater (that is, 4, 8, or 16 ohms). The
lower the ohm rating, the greater the power output. We recommend the use of 4 ohm
speakers for long-term usage. The TM300 delivers 150 watts of power per channel into
4 ohms at less than 1% THD (Total Harmonic Distortion). In order to ensure correct
phase correlation, the tip of the TM300 speaker jack should be connected to the “+”(hot)
input of your loudspeaker, and the sleeve of the TM300 speaker jack should be
connected to the “-”(ground) input of your loudspeaker. Note that, when the Aux 1 /
Monitor switch (see # 19 on page 8) is pressed in, the TM300 operates in a “split mono”
configuration, where the left speaker output carries the main stereo output (internally
mixed to mono) and the right speaker output carries Aux send 1.
5: Power on-off switch - As you may have guessed, this is what you use to turn the
TM300 on and off. If the TM300 is connected to external power amps (via its Main Insert
and/or Mono output jacks—see #4 and #5 on page 6 in this manual), turn it on before
you turn on the connected amps—and turn it off after the connected amps are turned off.
6: Fan - This variable-speed fan provides vital cooling to your TM300 power amp
(the hotter the amp gets, the faster the fan blows!). Make sure that cool, fresh air is
accessible at all times. Also, try to ensure that the TM300 is used in a dust-free
environment.
11
CAUTION
RISK OF ELECTRIC SHOCK
DO NOT OPEN
AVIS;
RISQUE DE CHOC ELECTRIQUE
NE PAS OUVRIR
DO NOT EXPOSE THIS EQUIPMENT
TO RAIN OR MOISTURE.
SAMSON
TM300 6 CHANNEL 150WATT STEREO MIXER
SPEAKER
OUT
RL
CAUTION:
DO NOT BLOCK AIRFLOW
46
35
2
1
ON
OFF
POWER
USE CLASS 2 WIRING
MINIMUM LOAD
IMPEDANCE 4
SERIAL NUMBER
CAUTION: TO REDUCE THE
RISK OF FIRE, REPLACE ONLY
WITH SAME TYPE FUSE.
AC INPUT
115V/230V,50/60Hz
780W
FUSE
8A/250V(115V)
4A/250V(230V)
Ω
ENGLISH

12
Connecting the TM300
The actual connections you’ll make to and from the TM300 will vary according to the
environment you use it in and the particular equipment you have. Here are a few basic
rules concerning TM300 connections that will apply in most situations:
•In general, it’s best to make all connections with the TM300 turned off. If you must
make connections with the power on, make sure that all faders are completely down
(at their “∞”position). If the TM300 is connected to any external power amplifiers,
turn them off first. Wait a few seconds for their power supplies to discharge and
then turn off all other connected equipment, turning the TM300 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 TM300 will accept unbalanced connectors
throughout, it specifically provides electronically balanced inputs for all mono
channel line inputs. The wiring diagram below shows how 1/4" TRS
(Tip/Ring/Sleeve) connectors should be wired:
XLR connectors for mono channel mic-level inputs should be wired as follows:
Unbalanced cables use standard 1/4" phone connectors, wired as follows:
•Always 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 “Grounding Techniques”section on page 16 in this manual for
information on how to avoid grounding problems.
•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 - 4 and line level signals into the remaining channels)—just
don’t have both kinds of inputs connected to the same channel.
•There are two “hidden”(or at least not so obvious) stereo inputs to the TM300; these
are the Auxiliary returns. Use these whenever you want to bring in stereo signals
that will not need to be equalized or otherwise processed.
•Channel and Main insert cables (sometimes called “Y-cords”) should terminate in
standard 1/4" TRS jacks (ring to send and tip to return), wired as follows:
TIP +
GROUND
RING -
RING
TIP SLEEVE
+ SIGNAL
GROUND
+ SIGNAL GROUND
3
-
SIG
NA
L
1 GROUND
2 + SIGNAL
T
TO MIC
TIP (RETURN)
SLEEVE (GROUND)
RING (SEND)
ENGLISH

13
TM300 Interconnections - Stereo Configuration
The illustration below shows typical interconnections between the TM300 and other audio equipment when used in its
standard stereo configuration (that is, with the Aux 1 / Monitor switch [see #19 on page 8] out).
40
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OOOO OO
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OO
OOOO OO
20
16
12
8
4
10
INSERT
LINE
MIC
1
INSERT
LINE
MIC
2
INSERT
LINE
MIC
3
INSERT
LINE
MIC
4
MIC
5
MIC
6
123456 L–STEREO–R
0
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0
L
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M
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TRIM
–6 –50
+14 –30
TRIM
–6 –50
+14 –30
TRIM
–6 –50
+14 –30
TRIM
–6 –50
+14 –30
TRIM
–6 –50
+14 –30
TRIM
–6 –50
+14 –30
PEAK PEAK PEAK PEAK PEAK PEAK
HIGH
–15 +15
0
MID
–12 +12
0
LOW
–15 +15
0
LOW
–15 +15
0
LOW
–15 +15
0
LOW
–15 +15
0
LOW
–15 +15
0
LOW
–15 +15
0
MID
–12 +12
0
MID
–12 +12
0
MID
–12 +12
0
MID
–12 +12
0
MID
–12 +12
0
HIGH
–15 +15
0
HIGH
–15 +15
0
HIGH
–15 +15
0
HIGH
–15 +15
0
HIGH
–15 +15
0
AUX 1 PRE
+10
AUX 2
+10
00
0
00
0
00
0
0
0
0
0
0 0
L R
PAN
AUX 1 PRE
+10
AUX 2
+10
L R
PAN
AUX 1 PRE
+10
AUX 2
+10
L R
PAN
AUX 1 PRE
+10
AUX 2
+10
L R
PAN
AUX 1 PRE
+10
AUX 2
+10
L R
PAN
AUX 1 PRE
+10
0
LEVEL
HEADPHONE
+10
0
REV TO AUX 1
+10
0
AUX SEND 1
+10
0
AUX RET 1
+10
0
TAPE IN
VOCAL
L HALL
S HALL
ON
METER HEADPHONE
SOURCE
AUX 1 / 2
RIGHTLEFT
L / R
PHANTOM
+10
0
AUX SEND 2
+10
0
AUX RET2/REV
+10
REC OUT
+4
L R
PAN
+12dB
0dB
-12dB
6.4KHz2.5KHz1KHz400Hz160Hz63Hz 15KHz
+12dB
0dB
L
R
-12dB
6.4KHz2.5KHz1KHz400Hz160Hz63Hz 15KHz
RIGHT
AUX2
+2
+4
0
–2
–4
–9
–12
–15
–20
–25
ON
OFF
EQ ON/OFFAUX 1/MONITOR
6 CHANNEL 150 WATT STEREO MIXER
REC OUT
+4dBu
TAPE IN
–10dB
LR LR
AUX SEND 1
MONO OUT+4dB
AUX SEND 2
+4dB
R
L
L/MONO
AUX RET1
+4dB
AUX RET 2 POST EQ
INSERT
R
DSP
SAMSON
AUX 2
+10
PFL
PFL PFL PFL PFL PFL
LINE LINE MAIN
6.4KHz2.5KHz1KHz400Hz160Hz63Hz 15KHz
+2
+4
0
–2
–4
–9
–12
–15
–20
–25
LEFT
AUX1 POWER
CAUTION
RISK OF ELECTRIC SHOCK
DO NOT OPEN
AVIS;
RISQUE DE CHOC ELECTRIQUE
NE PASOUVRIR
DO NOT EXPOSE THIS EQUIPMENT
TO RAIN OR MOISTURE.
SAMSON
TM300 6 CHANNEL 150WATT STEREO MIXER
SPEAKER
OUT
RL
CAUTION:
DO NOT BLOCK AIRFLOW
ON
OFF
POWER
USE CLASS 2 WIRING
MINIMUM LOAD
IMPEDANCE 4
SERIAL NUMBER
CAUTION: TO REDUCE THE
RISK OF FIRE, REPLACE ONLY
WITH SAME TYPE FUSE.
AC INPUT
115V/230V,50/60Hz
780W
FUSE
8A/250V(115V)
4A/250V(230V)
Ω
MIDI KEYBOARD
CASSETTE or DAT
+15db
0
-15db
0
+15db
-15db -15db
+15db
0
+15db
-15db
0
SAMSON
SIGNAL PROCESSOR
Ring Tip
SIGNAL PROCESSOR
RL
SIGNAL PROCESSOR
SERVO - 240
SAMSON
Ring Tip
R
L
RL
STEREO PARAMETRIC EQ
STEREO COMPRESSOR
Tip Ring
Tip Ring
Tip Ring
Tip Ring
LR LR LR
LR
ENGLISH

TM300 Interconnections - Split Mono Configuration
The illustration below shows typical interconnections between the TM300 and other audio equipment when used in its
“split mono”configuration (that is, with the Aux 1 / Monitor switch [see #19 on page 8] pressed in). Note that , in this
conguration, the Rev To Aux 1 Level control (#16 on page 8) can be used to route internal DSP signal to the onstage
wedge monitors (the Aux 2 Return Level can still be used to route DSP signal to the main PA speakers as well).
14
40
0
OO
OO
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25
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15
10
40
0
OO
OO
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30
25
20
15
10
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0
OO
OO
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10
40
0
OO
OO
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15
10
40
0
OO
OO
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30
25
20
15
10
40
0
OO
OO
35
30
25
20
15
10
26
0
OO
OOOO OO
20
16
12
8
4
10
26
0
OO
OOOO OO
20
16
12
8
4
10
INSERT
LINE
MIC
1
INSERT
LINE
MIC
2
INSERT
LINE
MIC
3
INSERT
LINE
MIC
4
MIC
5
MIC
6
123456 L–STEREO–R
0
L
I
N
E
M
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C
0
L
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M
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C
0
L
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M
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0
L
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M
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0
L
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E
M
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C
0
L
I
N
E
M
I
C
TRIM
–6 –50
+14 –30
TRIM
–6 –50
+14 –30
TRIM
–6 –50
+14 –30
TRIM
–6 –50
+14 –30
TRIM
–6 –50
+14 –30
TRIM
–6 –50
+14 –30
PEAK PEAK PEAK PEAK PEAK PEAK
HIGH
–15 +15
0
MID
–12 +12
0
LOW
–15 +15
0
LOW
–15 +15
0
LOW
–15 +15
0
LOW
–15 +15
0
LOW
–15 +15
0
LOW
–15 +15
0
MID
–12 +12
0
MID
–12 +12
0
MID
–12 +12
0
MID
–12 +12
0
MID
–12 +12
0
HIGH
–15 +15
0
HIGH
–15 +15
0
HIGH
–15 +15
0
HIGH
–15 +15
0
HIGH
–15 +15
0
AUX 1 PRE
+10
AUX 2
+10
00
0
00
0
00
0
0
0
0
0
0 0
L R
PAN
AUX 1 PRE
+10
AUX 2
+10
L R
PAN
AUX 1 PRE
+10
AUX 2
+10
L R
PAN
AUX 1 PRE
+10
AUX 2
+10
L R
PAN
AUX 1 PRE
+10
AUX 2
+10
L R
PAN
AUX 1 PRE
+10
0
LEVEL
HEADPHONE
+10
0
REV TO AUX 1
+10
0
AUX SEND 1
+10
0
AUX RET 1
+10
0
TAPE IN
VOCAL
L HALL
S HALL
ON
METER HEADPHONE
SOURCE
AUX 1 / 2
RIGHTLEFT
L / R
PHANTOM
+10
0
AUX SEND 2
+10
0
AUX RET2/REV
+10
REC OUT
+4
L R
PAN
+12dB
0dB
-12dB
6.4KHz2.5KHz1KHz400Hz160Hz63Hz 15KHz
+12dB
0dB
L
R
-12dB
6.4KHz2.5KHz1KHz400Hz160Hz63Hz 15KHz
RIGHT
AUX2
+2
+4
0
–2
–4
–9
–12
–15
–20
–25
ON
OFF
EQ ON/OFFAUX 1/MONITOR
6 CHANNEL 150 WATT STEREO MIXER
REC OUT
+4dBu
TAPE IN
–10dB
LR LR
AUX SEND 1
MONO OUT+4dB
AUX SEND 2
+4dB
R
L
L/MONO
AUX RET1
+4dB
AUX RET 2 POST EQ
INSERT
R
DSP
SAMSON
AUX 2
+10
PFL
PFL PFL PFL PFL PFL
LINE LINE MAIN
6.4KHz2.5KHz1KHz400Hz160Hz63Hz 15KHz
+2
+4
0
–2
–4
–9
–12
–15
–20
–25
LEFT
AUX1 POWER
MIDI KEYBOARD
CASSETTE or DAT
+15db
0
-15db
0
+15db
-15db -15db
+15db
0
+15db
-15db
0
SAMSON
SIGNAL PROCESSOR
Ring Tip
SIGNAL PROCESSOR
RL
SIGNAL PROCESSOR
Ring Tip
R
L
RL
MONO COMPRESSOR
MONO COMPRESSOR
Tip Ring
Tip Ring
CAUTION
RISK OF ELECTRIC SHOCK
DO NOT OPEN
AVIS;
RISQUE DE CHOC ELECTRIQUE
NE PASOUVRIR
DO NOT EXPOSE THIS EQUIPMENT
TO RAIN OR MOISTURE.
SAMSON
TM300 6 CHANNEL 150WATT STEREO MIXER
SPEAKER
OUT
RL
CAUTION:
DO NOT BLOCK AIRFLOW
ON
OFF
POWER
USE CLASS 2 WIRING
MINIMUM LOAD
IMPEDANCE 4
SERIAL NUMBER
CAUTION: TO REDUCE THE
RISK OF FIRE, REPLACE ONLY
WITH SAME TYPE FUSE.
AC INPUT
115V/230V,50/60Hz
780W
FUSE
8A/250V(115V)
4A/250V(230V)
Ω
ENGLISH

15
Setting up your TM300 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 TM300 is to be physically placed. Make sure that the rear vent and fan
are unobstructed and that there is good ventilation around the entire unit.
2. Before even plugging the TM300 into an AC socket, begin by making its speaker
connections. It is never a good idea to power up any amplifier that is not connected to
loudspeakers. Any loudspeakers with a minimum impedance load of 4 ohms (that is,
4 ohms or greater) can be used, but we recommend the use of 4 ohm speakers for
long-term usage. In order to ensure correct phase correlation, be sure that the
connection from the tip of the TM300 speaker jack goes to the “+”(hot) input of your
loudspeaker, and that the sleeve of the TM300 speaker jack is connected to the “-”
(ground) input of your loudspeaker.
2a. If you are planning to use the TM300 in a standard stereo configuration, make sure
the Aux 1 / Monitor switch is in its up (“out”) position and make connections between the
left speaker output(s) and your left main PA speaker(s) and between the right speaker
output(s) and your right main PA speakers. See page 11 for an example diagram.
2b. If you are planning to use the TM300 in a “split mono”configuration, make sure the
Aux 1 / Monitor switch is pressed in (“on”) and make connections between the left
speaker output(s) and your main PA speaker(s) and between the right speaker output(s)
and your onstage monitors. See page 12 for an example diagram.
3. Next, make all required connections to the various TM300 line-level outputs
(Record Out, Mono Out, and Aux Sends 1 and 2) and line-level inputs (Tape In, Aux
Returns 1 and 2). Do not make any insert connections at this time—these should be
made after the gain structure is correctly set (see pages 14 - 15).
4. Make the input connections to the mic or line inputs of the various channels.
WARNING: Do not connect a channel’s line input if you already have something
connected to its microphone input, or vice versa; each mono channel is designed to
accept only one source or the other.
5. Bring all channel faders and the left-right stereo faders completely down (to their “∞”
setting). Turn all Trim controls fully counterclockwise. Set the front-panel Phantom
switch to its “off”(out) position unless you are absolutely certain that all connected
microphones require 48 volt phantom power; if so, set the Phantom switch to its “on”(in)
position.
6. Plug the TM300 into any grounded AC socket using the supplied heavy gauge IEC
cord. Because of the special relay protection circuitry built into the TM300, you can even
plug it into the same power strip that other audio devices are connected to. You can
then turn on all devices at once with the single power strip on-off switch, with no danger
of damaging connected speakers by generating “thumps.”
7. Finally, press the rear panel Power switch in order to turn on the TM300.
The front-panel Power LED will go on.
Setting Up and Using The TM300
ENGLISH

16
You’re now ready to establish the correct gain structure—the key to getting the best
performance from the TM300, 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 in the previous section) but with the power
off, bring all channel faders and the left-right stereo faders completely down (to their “∞”
setting).
b. Turn all channel Trim controls fully counterclockwise.
c. Place all channel equalizer knobs in their center detent “0”positions and turn off the
seven-band graphic master equalizer by setting the EQ On/Off switches to their “Off”(up)
position.
d. Set the Meter/Headphone Source switch up (to its “L/R”position); this will ensure that
the TM300 meter shows the continuous level of the Left/Right stereo output signal.
e. Turn all channel Aux Send knobs and the main section Aux Return knobs to their fully
counterclockwise (“∞”) position. Turn the main section Tape In and Rev To Aux 1 knobs
to their fully counterclockwise (“∞”) position.
f. Set both main section master Aux Send knobs to their “0”(2 o’clock) position.
g. Power up all devices connected to the TM300 channel line inputs and Aux Returns
and set their level controls to unity gain or, if there is no unity gain indicated on their
output control, to maximum. If you’ve got outboard effects processors connected to the
Aux Returns, make sure they are sending completely “wet”(processed) signal, with no
“dry”(unprocessed) signal mixed in.
h. If condenser microphones are connected to the TM300, turn on the Phantom switch.*
Finally, turn on the TM300’s main power.
i. Play an instrument connected to one of the TM300’s line inputs** and, while doing so,
raise the corresponding channel fader to the “0”position. You should see the segment
meter begin to move—adjust the input Trim control for that channel so that the “0”
segment lights frequently and the “+3”segment lights only occasionally. The Peak LED
for that channel should not flash at even the highest level input signals. If the incoming
signal seems too hot even with the input channel Trim all the way at its minimum setting,
you may need to lower the output level of the instrument, though this will rarely occur.
Conversely, if the signal is too low even with the Trim all the way up, something’s
definitely wrong: in all likelihood, the connecting audio cable is faulty.
j. Once you’ve set the optimum level in step (i) above, continue playing the instrument
and slowly raise the stereo left/right faders until you reach the desired listening level.
* CAUTION: Before turning phantom power on, be sure to verify that all connected
mic(s) and/or active DI boxes require 48 volts. Also, disconnect all other signal sources
(such as passive DI boxes) from the XLR mic jacks.
** If you’re using an instrument such as electric guitar or bass, connect it to the TM300
with a direct injection box to ensure correct impedance.
Setting the Correct Gain Structure
ENGLISH

17
Setting the Correct Gain Structure
k. Repeat step (i) above for each instrument connected to TM300 channel line inputs.
l. 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
fader for that channel to its “0”position. Then adjust the Trim control for that channel
while watching the segment meter and channel Peak LED. You should expect that
microphone inputs will require rather more in the way of Trim boost than line inputs.
m. The general idea behind using the internal DSP is to drive it as hot as possible (short
of overloading it) and to then use the Aux Return 2 control to carefully set the amount of
processed signal you want to hear. (Note: When operating the TM300 in a “split mono”
configuration, the Aux Return 2 control determines the amount of processed signal in the
main [left] output and the Rev To Aux 1 Level control determines the amount of
processed signal in the monitor [right] output.) Press in the DSP On/Off switch to
activate the internal DSP and then select one of the three preset reverb effects for the
DSP. Begin by setting the Aux Return 2 control to its “0”(2 o’clock) position (this can
later be adjusted if you want to hear more or less processed signal). Next, using a
channel that has already had its gain structure adjusted in step (i) or (k) above, play the
instrument (or sing into the microphone) connected to that channel while slowly turning
the Aux Send 2 knob for that channel clockwise until you hear the desired amount of
processed signal added to the dry signal. If you hear any distortion, lower the amount of
signal being sent to the DSP by turning that channel’s Aux send 2 knob (or the main Aux
Send 2 knob) counterclockwise. For more information, see the “Using the Aux Sends
and Returns”and “Using DSP”sections on pages 20 and 22 in this manual.
n. If you have any outboard signal processors connected to the Aux send 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 TM300 Aux Sends. As with the internal DSP, the idea is to drive these
devices as hot as possible (short of overloading them) and then to use the 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 (i) or (k) above. Turn the Aux Send 1 knob for that channel to
its “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
just occasional higher excursions). Then it’s time to optimize the Aux Return level.
While continuing to play your instrument (or continuing to sing into the microphone),
slowly raise the Aux Return level control until you hear the desired amount of processed
signal added to the dry signal. Repeat for any external device connected to the Aux 2
Send jack (which is active only when the DSP On/Off switch is “off”). For more
information, see the “Using the Aux Sends and Returns”section on page 20 in this
manual.
o. The gain structure is now correctly set—you’ve optimized the level of all signals
coming into and out of the TM300, and the end result will be minimum noise and
distortion and maximum clean sound. You can now connect unity gain devices (such as
compressors, limiters, and noise gates) as needed to the channel and/or main inserts.
You’ll find that the majority of your mixes can be accomplished with most channel faders
at or near their 0 (unity gain) position and that the channel 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, use the main left/right stereo faders.
If you encounter difficulty with any aspect of setting up or using your TM300, you can call
Samson Technical Support (1-800-372-6766) between 9 AM and 5 PM EST.
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18
Grounding Techniques
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.
Three-prong plugs (such as the one used by the TM300) should always be used as is; don’t use adapters to lift the
ground (unless you’re using a “star ground network”—see below). If you hear hum or buzz from a device that uses
a two-prong plug (or an external two-prong AC/DC adapter), 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.
We also recommend that you use balanced audio cabling and connectors wherever possible. The TM300 provides
electronically balanced inputs for all channel line inputs. The wiring diagram in the “Connecting The TM300”section
of this manual (page 10) shows how 1/4" TRS (Tip/Ring/Sleeve) and XLR 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.
If you’re using the TM300 in a fixed location such as a rehearsal studio, you may want to invest the time and money
into creating a star ground network. This is by far the best technique for avoiding grounding problems. It involves
using a formidable ground source such as a cold water pipe or a copper spike driven into the earth. A thick
grounding cable is connected to that source and then brought to a central distribution point; from there, individual
cables are connected to each piece of equipment. This setup also requires that you lift the ground plug of all
three-prong AC connectors, so there is the possibility of danger if it is done incorrectly. We strongly recommend
that you contract with a qualified professional to carry out this or any kind of electrical work.
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).
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19
Using Equalization
One of the most exciting aspects of using a mixer such as the TM300 is the ability to
shape a sound, using a process called equalization. But there are few areas of audio
engineering more misunderstood than equalization, and, just as good EQ can really help
a sound, bad EQ can really hurt it, so read on...
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 frequency areas. The TM300 provides a seven-band graphic master
equalizer (more about this shortly) as well as independent three-band equalization
controls for each of its channels.
Each EQ knob is labeled with the maximum amount of cut or boost provided (± 15 dB in
the case of Low and High frequencies, and ±12 dB in the case of the Mid frequency).
The Mid frequency control utilizes a resonant (“bell”) peaking curve, while the Low and
High frequency controls utilize shelving curves. This means that, in the case of the Mid
EQ control, frequencies around 1.8 kHz are affected; in the case of the Low EQ control,
frequencies around or below 100 Hz are affected; and, in the case of the High EQ
control, frequencies around or above 10 kHz are affected. 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 (“0”), it is having no effect. When it is
moved right of center, the selected frequency area is being boosted; when it is moved
left of center, the frequency area is being attenuated.
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). 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”; con-
versely, you may want to attenuate the low frequency component of instruments such as
cymbals, high-hats, and shakers so as to “thin”them out. Boosting Mid frequencies can
be used to help bring out vocals or guitars, while attenuating them can help to reduce
“boxiness.”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. Finally, because the TM300 High and Low EQ utilize shelving curves,
attenuated High settings can be used to reduce hiss (which is composed almost
exclusively of high frequencies) or attenuated Low frequencies can be used to reduce
rumble (which is composed almost exclusively of low frequencies).
HIGH
-15 +15
0
MID
-12 +12
0
LOW
-15 +15
0
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20
Using Equalization
The seven-band graphic master equalizer affects the overall output signal of the TM300.
Its main function is to allow you to “tune”the device to the particular room environment
you are in. Perhaps its most important job is to enable you to eliminate ringing or
feedback problems caused when a microphone is too close to a loudspeaker. To
accomplish this, start with all seven bands flat (that is, all seven sliders at their detented
“0”center position). Then, one by one, raise each slider until you hear the feedback or
ringing markedly increase. This allows you to identify the problematic frequency area
(it will most commonly be one or more of the high mid-range or high frequency areas).
When you’ve located the problem area(s), it’s simply a matter of lowering that slider or
sliders below the 0 point until the ringing or feedback disappears. Don’t lower the
frequency area any further than you need to, or the quality of the overall sound may
suffer. If you don’t specifically need to utilize the TM300’s seven-band graphic master
equalizer in a particular environment, deactivate it by setting one or both EQ on/off
switches to their Off (up) position.
Note that, when the Aux 1 / Monitor switch is pressed in, the TM300 functions in a “split
mono”configuration. In this configuration, the left side of the graphic equalizer
processes the main stereo output (which is internally mixed to mono and routed to the
TM300’s left speaker outputs, normally connected to main PA speakers), while the right
side of the graphic equalizer processes the Aux 1 send output (which is internally routed
to the TM300’s right speaker outputs and normally connected to onstage monitors).
In this way, you can have separate equalization curves for both main (“Front Of House”)
PA speakers and your onstage monitors without the need to purchase an outboard
equalizer (or external power amplifier). See page 12 in this manual for an
interconnection diagram which shows this kind of usage.
+12dB
0dB
6.4KHz2.5KHz1KHz
400Hz160Hz63Hz 15KHz
-12dB
EQ ON/OFF
AUX1/MONITOR
LEFT RIGHT
+12dB
0dB
6.4KHz2.5KHz1KHz
400Hz160Hz63Hz 12KHz
-12dB
6.4KHz2.5KHz1KHz
400Hz160Hz63Hz 15KHz
Seven-band graphic master equalizer
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