Yamaha PM4000 User Manual

PROFESSIONAL AUDIO MIXING CONSOLE

PM4000

OPERATING MANUAL

YAMAHA

PM4000

OPERATING MANUAL

IMPORTANT NOTICE FOR THE UNITED KINGDOM

Connecting the Plug and Cord
WARNING : THIS APPARATUS MUST BE EARTHED

IMPORTANT. The wires in this mains lead are coloured in accordance with the following code:

:

GREEN-AND-YELLOW
BLUE
BROWN

As the colours of the wires in the mains lead of this apparatus may not correspond with the
coloured markings identifying the terminals in your plug proceed as follows:

The wire which is coloured GREEN-AND-YELLOW must be connected to the terminal in the
plug which is marked by the letter E or by the safety earth symbol or coloured GREEN or
GREEN-AND-YELLOW.

The wire which is coloured BLUE must be connected to the terminal which is marked with the
letter N or coloured BLACK.

The wire which is coloured BROWN must be connected to the terminal which is marked with the
letter L or coloured RED.

* This applies only to products distributed by YAMAHA - KEMBLE MUSIC (U.K.) LTD.

EARTH

:

NEUTRAL

:

LIVE

Professional audio mixing console Typ : PM4000

82/499/EWG

YAMAHA Europa GmbH

MICROPHONE CABLES AND MICRO­PHONES CONNECTION

TO PREVENT HAZARD OR DAMAGE,

ENSURE THAT ONLY MICROPHONE
CABLES AND MICROPHONES DESIGNED

TO THE IEC268-15A STANDARD ARE

This product complies with the radio frequency
interference requirements of the Council Direc­tive 82/499/EEC and/or 87/308/EEC.

CONNECTED.

YAMAHA CORPORATION

How to Use This Manual

If you are an engineer or technician who is familiar
with sound system design, much of this manual will
serve as a review for you. The basic features are
presented in the “BRIEF OPERATING INSTRUC­TIONS” section. Check this and the “SPECIFICA­TIONS” section, and you will see most of what you
need to know. The balance of this manual provides
background information for better utilization of the
console and auxiliary equipment.

If you would like to know more about AC power

distribution and safety, grounding, balanced versus
unbalanced cables, direct boxes, and so forth, this
information is also presented. Check the TABLE OF

CONTENTS.

There are internal preset switches within the
console which can be configured to change the func­tions and/or signal paths in certain circuits. Refer to
the OPTIONAL FUNCTIONS section for details.

Terminology and
Typographic Conventions

Generally, where we refer to a particular control or

function as it is actually labeled on the console, we

will use all upper case type. That is, if we refer to an
input channel’s gain control, we may print “the input
GAIN control.” On the other hand, if the feature is not
labeled, we will use upper case type only on the first
letter; for example, “observe there is no identification
of the input Fader.” If the front panel label is incom­plete or ambiguous, we may augment it. For example,
the input channel pushbutton switches labeled “1, 2,

3, 4, 5, 6, 7, 8” may be accompanied by the parenthetic

reference “(group bus assign)“.

Particularly important information is distin-

guished in this manual by the following notations:

NOTE: A NOTE provides key information to

make procedures or functions clearer or easier.

CAUTION: A CAUTION indicates
special procedures or guidelines
that must be observed to avoid dam­age to the console or related equip­ment, or to avoid an undesirable
result while using the console.

WARNING: A WARNING indicates

special procedures or guidelines
that must be observed to avoid in-

jury to the operator or others using

or exposed to the console or related
equipment.

In the BRIEF OPERATING INSTRUCTIONS

section of this manual, each feature is provided with a

numerical reference. Elsewhere, if we are referring to

that feature, we may cite the reference number in
square brackets for clarity. For example, on the input
module, the fourth control to be described is the PAN
pot. In other places on the console there are other
PAN pots. For clarity, then, if we are discussing this
particular input PAN pot, we will describe it like this:
"the PAN pot [2]". Now, here’s a real warning that
Underwriters Laboratories says we have to print:

Warning: To prevent fire or shock
hazard, do not expose this appliance
to rain or moisture.

There are eight groups (or subgroups, depending
on your linguistic preference). The group faders are
known as “Group Master Faders”. Their function is to
control the level on the eight “Group Mixing Busses.
The eight group busses are different and distinct from
the eight “Auxiliary Mixing Busses. The Stereo Fader
is actually a pair of closely spaced faders (L and R);
when we refer to the general function, we use the
term “Stereo Fader,” but if the availability of separate
left and right control is important, we may use the
plural “Stereo Faders.”

Page A-1

Table of Contents

Page Sect. Title

Section 1. Introduction
Section 2. Brief Operating Instructions

2-1
2-1

2-7

2-12

2-17
2-19
2-22
2-25
2-27
2-34 2.4

PM4000 Front Panel Features

2.1

2.1.1 The Standard Monaural Input Module

2.1.2 The Stereo Input Module

2.1.3 The Master Module (1 - 8)

2.1.4 The Stereo Master Module

2.1.5 The TB (Talkback) Module

2.1.6 The Monitor Module

2.1.7 The Meter Bridge
PM4000 Rear Panel Features

2.2

The PW4000 Power Supply

Section 3. Specifications

3-1

PM4000 Mixing Console General Specifications

3-2

PW4000 Power Supply Specifications

3-3

PM4000 Input Characteristics

3-3

PM4000 Output Characteristics

Dimensional Drawings

3-4

Block Diagrams

3-7

Section 4. Installation Notes

4-1
4-1
4-1
4-1
4-2

4-3

4-3

4-4

4-4

4-4
4-5
4-5
4-6
4-7
4-8
4-9
4-10

4-10
4-10
4-13
4-14

4-15 4.5 Direct Boxes

Planning An Installation

4.1
Power Mains

4.2

4.2.1 Verify The Correct Mains Voltage

4.2.2 Ensure There is a Good Earth Ground

4.2.3 How To Obtain a Safety Ground When
Using a 2-wire Outlet

4.2.4 Improperly Wired AC Outlets: Lifted
Grounds

4.2.5 Improperly Wired AC Outlets: Lifted

Neutral

4.2.6 AC Safety Tips

4.2.7 Power Source Integrity

4.2.8 Turn-On Sequencing

4.3 Theory of Grounding

4.3.1 Why Is Proper Grounding Important?

4.3.2 Ground Loops

4.3.3 Basic Grounding Techniques

4.3.4 Balanced Lines and Ground Lift Switches
Audio Connectors and Cables

4.4

4.4.1 Types of Cable To Use

4.4.2 Cable Layout

4.4.3 Balanced versus Unbalanced Wiring

4.4.4 The Pro’s And Con’s of Input Transformers

4.4.5 Noise And Losses In Low and High
Impedance Lines

Page Sect. Title

4-15
4-17
4-17 4.6 Configuring Equipment Racks

Section 5. Gain Structure and Levels

5-1
5-2
5-2
5-2

5-2
5-2

5-4
5-4

5-6

Section 6. Optional Functions

6-2

6-3

6-4
6-5 6.4

6-6

6-7

6-8
6-9

6-10 6.9
6-11 Stereo Input Channel Stereo

6-12 6.11 Stereo Input Channel Feed to Monitor

6-13 6.12 Phase Switch Function: Change Polarity of

6-14 6.13 Stereo Input Module: Output Enable

6-15 6.14 Master Module: Group-to-Matrix Assigned

4.5.1 Passive Guitar Direct Box

4.5.2 Active Guitar Direct Box

5.1 Standard Operating Levels

5.2 Dynamic Range and Headroom

5.2.1 What Is Dynamic Range?

5.2.2 The Relationship Between Sound Levels and
Signal Levels

5.2.3 A Discussion Of Headroom

5.2.4 What Happens When The Program Source

Has Wider Dynamics Than The Sound

Equipment?

5.2.5 A General Approach To Setting Levels In a
Sound System

5.2.6 How To Select a Headroom Value and
Adjust Levels Accordingly

5.3 Gain Overlap And Headroom

6.1 Removing and Installing A Module

6.2 Mono Input Direct Out Jack:

Pre-Fader or Post-Fader (switch)
Pre-ON or Post-ON Switch (jumper)

6.3 Mono Input Aux Sends: Pre Fader & EQ or

Pre Fader/post EQ
Mono Input Cue/Solo Switch: Pre-Fader or

Follow MT PRE Switch

Stereo Input Cue/Solo Switch: Pre-Fader or

6.5
Follow MT PRE Switch

6.6

Mono & Stereo Input Channel MT PRE
Switch: Pre- or Post-ON Switch
Stereo Input Channel Insert In/Out Jacks:

6.7
Pre-EQ or Post-EQ

6.8 Stereo Input Channel Aux Sends:
Pre Fader & EQ or Pre Fader/Post EQ
Stereo Input Channel Aux Sends 1-8:
L+R Blend or Stereo Pairs

6.10
Aux Sends 1 & 2: L+R Blend or Stereo Pairs

Module ST IN 3 or ST IN 4

Both L and R inputs, or of L Only

Jumpers to Group, Stereo and Aux Busses

Pre or Post Group Master Fader

Page TC-1

Page Sect. Title

6-16

6.15 Stereo Master to Matrix ST Bus: Pre or Post
ST Master Fader

6-17

6.16 Installation of Optional Input Transformers

6-18

6.15 Hints on Circuitry For Remote Control of

the VCA Masters and Mute Groups

Section 7. Operating Notes and Hints

7-1 7.1 Console Gain Structure

7-l 7.1.1 What Is The Proper Gain Structure?
7-1

7.1.2 What Affects Gain Structure?

7-1

7.1.3 Establishing The Correct Input Channel
Settings

7-2

7.1.4 Establishing The Correct Group Master
Settings

7-2

7.1.5 Establishing The Correct Aux Send Master
Settings

7-2

7.1.6 Establishing The Correct Mix Matrix
Settings

7-3

7.1.7 Establishing The Correct Aux Return
Settings

7-3

7.1.8 How VCA Control Affects Gain Structure

7-4

7.1.9 Channel Muting and Gain Structure

7-4

7.2 Further Hints & Conceptual Notes

7-4

7.2.1 What Is a VCA, and Why Is It Used?

7-4

7.2.2 The Distinction Between The Group Busses

and The VCA Master “Groups”

7-7

7.2.3 Using The Channel Insert In Jack as a

Line Input

7-7

7.2.4 Understanding and Using The Mix Matrix

7-9

7.2.4.1

7-9 7.2.4.2

7-9

7.2.4.3

7-10 7.2.4.4 Use of the Matrix to

7-10

7.2.5 Understanding and Use of The Master Mute

7-12

7.2.6 Stereo Panning To the Eight Group Mixing

The Mix Matrix In General Sound
Reinforcement

Using The Matrix Sub Inputs
For Effects

Other Uses For The Matrix
Sub Inputs

Pre-Mix Scenes

Function

Busses

Page Sect. Title

Section 8. Applications

8-1
8-1
8-1
8-2
8-2
8-3
8-3
8-3
8-4

8-4

8-6

8-7

Section 9. Maintenance

9-l
9-1
9-1
9-1
9-1
9-2
9-2
9-3

8.l General

8.1.1 Theatre

8.1.2 Production

8.1.3 Post Production

8.1.4 Video

8.1.5 Sound Reinforcement

8.2 Setup Concepts

8.2.1 Deriving A Stereo Mix From Groups 1 - 8

8.2.2 The Mix Matrix Allows the 8 Groups Plus
the Stereo Bus to Function as 10 Subgroups

8.2.3 How To Get 5 Independent Stereo Mixes or
10 Mono Mixes by Using the Stereo Bus
Plus the Mix Matrix

8.2.4 How to Use the VCA Masters Plus the

Group Master Faders to Obtain the

Functional Equivalent of 16 Subgroups

8.2.5 Using More Than One VCA Master to
Control the Same Input Channels In Order

To Handle Overlapping Scenes

9.1

Cleaning The Console

9.1.1 The Console and Power Supply Exterior

9.1.2 Power Supply Air Filters

9.1.3 Pots And Faders

9.1.4 The Console Interior

9.2

Meter Lamp Replacement

9.3

Where To Check If There Is No Output

9.4

What To Do In Case of Trouble

Page TC-2

Section 1

Introduction

Section 1.

Introduction

The PM4000 is a professional audio mixing console
with the kind of flexibility, performance and reliability
for which Yamaha has earned a worldwide reputation.
It picks up where the famous PM3000 left off, with still
more functions, a higher level of performance, and a
greater degree of versatility than ever before. The

console now comes with both mono and stereo input

modules, and you can determine the complement of

each type of module in your unit at the time you order

it, or you can later swap modules in the field (between

shows if need be).

The console is available with 24, 32, 40 or 48 input
positions (24 channel versions are available in the
U.S.A. only on special order). However, if fully config­ured with stereo input modules, the actual number of
input

sources

and stereo modules can add up to no more than 64 in­put channels per mainframe, as limited by power
supply capacity). There are eight VCA (Voltage Con­trolled Amplifier) Master Faders which can be assigned
to control any combination of input channels (see

Section 7 for a discussion of VCAs). In addition, there
are eight group mixing busses, as well as a stereo

mixing bus, to which any of the input channels can be-

assigned. There are also eight monaural auxiliary
mixing busses and two pair of stereo auxiliary mixing
busses to which each input channel may be assigned by

means of sealed PRE/OFF/POST switches and Send

Level controls. The stereo aux busses may be switched

to dual mono busses, for a total of twelve busses that

can be used to augment the eight groups plus the stereo

bus for a total of 22 audio mixing busses, or they may be

used for a combination of foldback send (stage monitor),

effects send and remote mixes.

Input channel signals may be assigned directly to the

stereo bus, or assignment can be made via the Group

Masters. Thus, the console can function in a sub­grouped mode with a stereo "grand master" fader, or it
can function with independent stereo and multi-channel
output mixes.

The PM4000 inputs are differentially balanced, and

are equipped with a 30 dB attenuation PAD plus a

continuously variable 50 dB range GAIN trim control so

that literally any mic or line level signal can be accom-

modated with channel faders set at nominal level.
Optional input transformers may be installed internally
on a channel-by-channel basis when extra grounding
isolation is required. While the console has ample
headroom throughout, it is always possible to incor-

is

substantially higher (the mix of mono

rectly set controls. For this reason, the PM4000 is
equipped with level detection at several stages. Input
LED meters and "PEAK" LEDs are provided. The latter
not only monitor the input preamp level, they check for
overboost in the EQ section. too. Metering can be front­panel switched to pre or post fader (actually, pre/post
VCA). Finally, if the mixed levels on the group, auxil-

iary, stereo, matrix or cue busses adds up to be too high,
a “PEAK” LED in the output meters will flash on to

warn of the impending danger of clipping.

Matrix, the feature Yamaha pioneered in professional

audio consoles. The PM4000 Mix Matrix is an 11x8

configuration. That is, there are 11 possible sources that

can be mixed together into one output. Those 11 sources

can be mixed together eight different ways on eight

different modules. Each matrix channel accepts a direct
sub input from a rear panel connector, plus signals from

the stereo bus (L&R) and the eight subgroups (pre or

post master fader, depending on internal preset
switches). These 11 sources all go through a MATRIX
MASTER control and an on/off switch to a discrete rear
panel output. The matrix can save a tremendous
amount of time and effort when you want to set up

stage monitor mixes from the subgroups, when you

want to create different speaker mixes for different

zones of the house, to feed local and remote programs
simultaneously, to make mono and stereo mixes from

the same subgroups, and so on. In fact, if the matrix is

set to pick up the subgroups ahead of the Group Master
Faders, then the subgroups can be mixed onto the
stereo bus with one mix, and completely independent
mono or stereo mixes can be achieved from the same

subgroups via the matrix.

separate from the audio grouping. Eight "VCA GROUP"
switches next to each channel fader enable that channel
to be assigned so it is controlled by one or more of the

VCA Master Faders. When multiple input channels are

assigned to a given VCA bus, those channels output
levels can be raised or lowered by the single VCA
Master Fader. Consider how this differs from the
conventional groups. When multiple input channels are

assigned to one of the eight group (audio) mixing

busses, those channels’ combined signals can be raised

or lowered in level with the Group Master Fader. The
audio result is the same as though the VCA Masters
were used... with one exception; if signal processing of
multiple inputs is required, it is necessary to run that

Naturally, the PM4000 is equipped with a Mix

The PM4000 has a VCA grouping system which is

Page 1-1

combined signal through a single bus, which is why full-length
Group Master Faders are provided on the PM4000. However,
when the VCA Master Faders are used, more than one VCA
Master can combine to alter the level of a single input channel.
What’s more, the VCA Master Fader, because it affects the input
channel directly, can also alter that channel’s post-Fader output
to any of the eight auxiliary mixing busses, something not
possible with the conventional Group Master Faders. Because
the VCA Master levels are voltage controlled, the PM4000 can be
automated, at least to the extent of controlling group levels. A
rear panel multi-pin connector can be used for this purpose.
These VCAs are sonically improved, and to insure reliable

operation, all bus, VCA group, and mute group assignments are

via proven latching switches; Yamaha has avoided C-MOS

switching and “glue-logic” for these vital functions.

The MASTER MUTE function facilitates scene changes and
complex cues. Each input channel has eight MUTE assign
switches. These permit the channel’s on/off function to be re­motely controlled by the eight MASTER MUTE switches. Once a
channel is switched on locally, it can be muted (turned off) or
unmuted (turned on) if it is assigned to one or more of the mute
groups. This permits multiple channels to be silenced or acti­vated all at once, which expedites live sound mixing, band
personnel or instrument changes, theatrical scene changes, and

so forth. If, however, it is imperative that a certain channel never

be inadvertently muted, or that muting temporarily be overrid-

den, the input channel’s MUTE SAFE switch can be engaged.

Muting can also be controlled remotely, via a rear panel connec-

tor, so automation here, too, is possible. In addition to the master
muting function, the VCA master faders have mute switches
which mute the corresponding VCA group (or at least prevent the
master from altering input levels); this provides another, differ­ent layer of master control of levels to facilitate tracking program
changes with the mix.

In recognition of the increasing trend toward full-function

auxiliary return, the PM4000 relies upon full-capability input
modules for aux returns. That's why the console is available with
up to 48 input channels, including stereo inputs. For added
flexibility, the INSERT in jack(s) on any input module can be
used for aux return purposes, and then the channels INSERT

ON switch can pick up the aux return instead of any signal

which may remain connected to the main channel input(s). This

allows a given channel to perform different functions at different

times without patching cables.

An excellent feature of the PM4000 is its extensive cue and

solo capability. There is a CUE/SOLO switch on every input

channel and on the aux returns, and a CUE switch on every
auxiliary send, the group outputs, the matrix outputs and the

Figure 1-1. PM4000 Modules (Left-to-Right):

Monaural Input (24, 32, 40 or 48 in console), Stereo

Input (at least 4 per console), Master, Stereo Master,

Talkback, and Monitor

Page 1-2

stereo master output. Cue replaces the signal in the
headphones and the stereo cue XLR outputs with only
those sources whose CUE switches are engaged.

The CUE system has input priority so that the
operator may normally monitor the cue signal from the
stereo bus or the group busses, and can instantly check
one or more channel or aux return inputs without

having to first release the bus CUE switches. This

capability is great for troubleshooting, previewing a
channel before applying it to the mix, or “touching up”
the EQ on a channel during a performance. For use
ahead of a live show, the console may be placed in solo
mode. In this mode, only the input channel(s) whose
CUE/SOLO switch is engaged will feed the console’s
outputs, and all other input channels will be muted. If
the stereo input modules are used for returns, recessed
switches in these modules can be set so returns will not

be muted and any effects applicable to the soloed input

will be heard. Annunciator lights signal the operator
whether the console is in solo or cue mode, and whether
any CUE or CUE/SOLO switch is engaged. Two head­phone jacks enable a pair of console operators (or an
engineer and producer) to work side-by side on complex
projects.

The PM4000 has an excellent talkback system plus
a useful test oscillator. An XLR input (with phantom
power) can be set to accept any microphone or line level
input, and is activated with the TALKBACK switch.
That signal can be slated to any of the eight group
mixing busses, the eight aux send mixing busses, the
two stereo aux busses, the stereo mixing bus, and to a
rear panel XLR TB output. The test oscillator can be set
to 100 Hz, 1 kHz or 10 kHz fixed frequencies, or can be
swept from 0.2 to 2x the set frequency, and its output
level is adjustable. Pink noise may be selected, too. The
oscillator can be slated to the same busses as the
talkback, and also has its own rear panel output connec­tor so the signal can be routed to other equipment or
other console inputs for testing.

Extensive metering is provided with a total of 14 VU
meters on the 24 and 32 channel versions, or 18 VU
meters on the 40 and 48 channel versions (each with a
peak LED). Several of these meters can be switched to
monitor alternate busses, so the metering gives you a

comprehensive view of signal levels in your system.

PM4000 electronic performance is everything you’d

expect from the people who developed the PM3000. It is
even more advanced, with lower noise levels than ever.
Wide headroom throughout, exceptionally low distor­tion, and quiet controls are the hallmark of this top

quality mixing console. The specifications are honest

and conservative. The performance is audibly superb.

Physically, the PM4000 is as appealing as it is
electronically. An all new chassis design with aircraft­style bracing offers increased strength to sustain
repeated trips on the road. A gray finish and subtly
color coded controls set the backdrop for the PM4000’s

hundreds of illuminated switches and indicators.

Multiple rear-mounted cooling fans reduce internal
temperatures to prolong component life.*

The highly advanced PM4000, with its many inter­nally switchable functions, is as close to a custom
console as you can get... while retaining all the value
and reliability of an off-the-shelf Yamaha console. While
its numerous internal and front panel functions may at
first intimidate the casual console operator, the PM4000
is actually a very straightforward console to use.
Anyone who has used the PM3000, or even a PM2000,

should immediately feel comfortable with the PM4000.
Take a while to study the panel, read the descriptions in
this manual, and you’ll find operating this console is
very natural... and satisfying because you can make it

do the job the way you need it done.

*Heat is generated by electronic components, and is the
enemy of them. In some segments of the. industry (such

as Las Vegas showrooms), it has been customary to leave
equipment switched on 24 hours. This tradition grew out

of the days when vacuum tube equipment was prevalent,

and vacuum tubes did last longer

rather than being switched. Solid state devices used in

modern mixing consoles are less susceptible to damage
from switching, but the heat build up sustained in

continuous 24 hour operation will shorten component

life. Therefore, it’s a good idea to turn off your equipment

when it is not in use (unless you are in a very humid

environment where the heat

corrosion-causing, short-circuit-promoting moisture

condensation). While the PM4000 remains cooler than

its predecessors, thanks to cooling

prudent practice to shut it off when it is not being used.

if they remained on

of operation wards off

fans, it remains a

Figure 1-2. PM4000-48 Rear Panel

Page 1-3

Section 2

Brief Operating Instruction

Section 2.
Brief Operating Instructions

2.1 PM4000 Front Panel
Features

NOTE: Features are numbered to correspond with the

numbers on these module drawings. In the case of the
input modules, where the standard monaural module
and stereo modules are similar, we have used the same

feature number where the features are identical. Where

the features are not identical, we have used an “S” suffix.
For example, feature [4] is the 48V phantom power
switch in both the monaural and the stereo input
modules, but the PAN switch and pot [2] on the stan­dard input module is not the same as the BAL/PAN
switch, and the concentric selector switch and pot [2S]
on the stereo input module.

Figure 2-1a. PM4000 Standard Input
Module (upper portion of module)

2.1.1

The Standard Monaural Input Module

1. 1 2 3 4 5 6 7 8 (ASSIGN switches)

These locking switches assign the channel output
to group mixing busses 1 through 8. An LED
indicator in each switch turns on when the signal
is assigned to the bus.

2. PAN (switch & rotary control)

The locking PAN switch activates the PAN pot so
you can use it to position signal between any odd­numbered and even-numbered group mixing
busses (provided the corresponding ASSIGN
switches are engaged). This lets you create up to
four additional stereo mixes. An LED in the
switch turns on when the PAN switch is engaged.
Center position applies 3 dB less signal to each
bus than the level obtained with full left or right
assignment so that the combined stereo signal
across a given pair of busses adds up to constant
power at all PAN pot positions.

3. ST (Stereo)

This locking switch assigns the channel output
directly to the stereo bus. An LED in the switch
turns on when the signal is assigned to the stereo
bus. If you want the cleanest, quietest stereo mix,
create it by assigning inputs directly to the stereo
bus with this switch rather than running signal
to group busses and then mixing the groups down
to stereo.

4. +48V

This switch turns phantom power on and off at
the channel’s XLR input connector. Power can be
turned on, however, only if the MASTER PHAN-

Page 2-1

TOM POWER switch is on. An LED in the switch
turns on when phantom power is being applied to
the channel input connector.

When both the Master and this switch are on,

+48 volts is applied to both pins 2 & 3 of the
channel input XLR connector for remote power­ing of condenser microphones. Although phantom
power will not harm most dynamic and other
non-phantom powered microphones or line-level
devices, connection of an unbalanced source to
the channel input could partially short the
console’s phantom supply, cause undue loading,

and induce hum. Therefore, it is a good practice
to turn off the channel’s phantom power unless it
is actually in use.

NOTE: The console's microphone power supply is not

intended for A-B powered microphones. External sup-

plies may be used with these devices, in which case the

console’s phantom power should be turned OFF on the
appropriate channels. The optional input transformers,
if installed, do not affect phantom power operation.

5. GAIN

This rotary knob provides 50 dB of continuously

variable adjustment for the input preamplifier

gain. A setting of -70 (full clockwise rotation)
provides maximum gain for low-level mic inputs,
whereas a setting of -20 provides minimum gain
for low-level line inputs or “hot” mics. These
settings provide 30 dB less overall gain when 30
dB pad is engaged [6].

6. 30 dB (pad switch)

Engaging this pushbutton switch attenuates the
signal 30 dB and turns on an LED in the switch.
The PAD should be used in conjunction with the
GAIN control to obtain the precise channel

sensitivity necessary for a given source. If you’re
not sure whether an input is high line level or
mic level, begin with the pad engaged, and the

GAIN control at -20 (+10) position. Then rotate

the GAIN control clockwise. If you still don’t get

enough level, or if the signal is noisy with a lot of

gain, then turn down the GAIN, disengage the

pad and reset the GAIN control as necessary.

NOTE: By adjusting the GAIN control, you may be able

to get the same overall level with or without the pad
engaged. Listen for noise and distortion, though; if the
signal is noisy, don’t use the pad. If there is a lot of
distortion, use the pad.

7. PEAK

This red LED turns on to indicate when the

signal present after the channel preamp is too

high in level. The LED triggers 3 dB below

clipping, and should therefore flash on only
occasionally.

This indicator measures signal from the XLR or
from the INSERT IN jack, whichever is active, as
well as after the equalizer. If necessary, use the
PAD or decrease the GAIN setting to prevent the
LED from remaining on any longer than momen-

tarily; otherwise excessive distortion and insuffi­cient fader travel will result.

8. Ø (Phase)

This switch reverses the polarity of pins 2 and 3
of the channel’s XLR input connector. In normal
position (switch button up), pin 2 is the signal
high conductor, and in reverse position (switch

engaged), pin 3 is high. An LED in the switch is

illuminated when polarity is reversed.

This eliminates the need to rewire connectors or
use adapters for out-of-phase (reversed polarity)
audio sources. Sometimes intentional polarity
reversal can be helpful in canceling leakage from

adjacent microphones, or in creating electro­acoustic special effects by mixing together out-of-

phase signals from mics picking up the same

sound source.

EQUALIZER

The input channel equalizer is divided into four
bands, each with sweepable filter frequencies.
The high and low bands may be switched for a
peaking or shelving type curve, whereas the high­mid and low-mid bands are of the peaking type.
All four bands have adjustable Q, providing fully
parametric type EQ. The level (gain) is adjustable

over a range of 15 dB boost and 15 dB cut in each
band.

9. HIGH (Peak/Shelf)

This locking switch selects peaking type EQ

(switch out) or shelving type EQ (switch en­gaged). When the switch is engaged (shelving

mode), the adjacent Q control is not operational.

Q

This rotary control adjusts the Q (the bandwidth)
of this section of the equalizer from a very narrow
band to a very broad band, with a center detent

at a Q of 1.2.

Front
panel

center position

Q

3.0

1.4

1.2

0.7

0.5

Bandwidth

(octave)

0.5

1.0

1.2

2.0

2.5

Channel EQ “Q” Characteristics

Page 2-2

1 ~ 20 kHz

The outer concentric knob sweeps the EQ Fre­quency between 1,000 and 20,000 Hz.

-15 ~ +15 dB

The inner concentric knob adjusts the gain of the
set frequency band by plus or minus 15 dB. A
center detent is provided for unity gain.

10. HIGH-MID
Q

This rotary control adjusts the Q (the bandwidth)
of this section of the equalizer from a very narrow
band to a very broad band, with a center detent
at a Q of 1.2.

0.4 ~ 8 kHz

The outer concentric knob sweeps the EQ Fre­quency between 400 Hz and 8,000 Hz.

-15 ~ +15 dB

The inner concentric knob adjusts the gain of the
set frequency band by plus or minus 15 dB. A
center detent is provided for unity gain.

11. LO-MID
Q

This rotary control adjusts the Q (the bandwidth)
of this section of the equalizer from a very narrow
band to a very broad band, with a center detent
at a Q of 1.2.

80 Hz ~ 1.6kHz

The outer concentric knob sweeps the EQ Fre­quency between 80 Hz and 1,600 Hz.

-15 ~ +15 dB

The inner concentric knob adjusts the gain of the
set frequency band by plus or minus 15 dB. A
center detent is provided for unity gain.

12. LO (Peak/Shelf)

This locking switch selects peaking type EQ

(switch out) or shelving type EQ (switch en­gaged). When the switch is engaged (shelving
mode), the adjacent Q control is not operational.

Q

This rotary control adjusts the Q (the bandwidth)

of this section of the equalizer from a very narrow
band to a very broad band, with a center detent

at a Q of 1.2.

30 Hz ~ 600 Hz

The outer concentric knob sweeps the EQ Fre-

quency between 30 and 600 Hz.

-15 ~ +15 dB

The inner concentric knob adjusts the gain of the

set frequency band by plus or minus 15 dB. A

center detent is provided for unity gain.

NOTE: PM3000 users will notice there is no EQ CLIP

indicator. Clipping at this stage can occur even though
the input signal is not clipping, due to boost (gain)
applied with the EQ circuitry. In the PM4000, clipping

in the equalizer is detected and shown on the PEAK

indicator [7] adjacent to the GAIN control.

13. EQ (In/Out switch)

This locking switch activates the channel EQ or
bypasses it completely. The EQ is active when the
switch is engaged (and the LED in it is on). Bypass
allows for A-B comparison, and absolutely mini­mum signal degradation when EQ is not needed.

14.

HPF (H.P. filter in/out switch and control)

This locking switch activates the input channel
HIGH PASS FILTER or bypasses it. The filter is
active when the switch is engaged (and the LED in
it is on). This filter bypass function is independent
of the EQ section, which has its own bypass switch.

20 ~ 400Hz

This rotary control sweeps the cutoff frequency of a
high pass filter (or "low cut" filter) from 20 Hz to

400

Hz. The filter slope is 12 dB per octave.

Typical applications including cutting wind noise,
vocal "P" pops, stage rumble, and low frequency
leakage from adjacent instruments. You can use
higher frequency settings to reduce leakage into
mics that are primarily handling high-frequency

sources. It is a good practice to use the filter to

protect woofers from unnecessary over-excursion

due to the presence of unneeded low frequency or
sub-sonic components, especially if a microphone is
dropped or kicked. Bypass the filter (switch up)
only when you want very low frequencies, as with
an organ, drum, bass guitar, and so forth.

15. INSERT PRE

The insert in point is normally after the HPF and

equalizer. Engaging this switch moves the insert
point between the equalizer (pre-EQ) and the
HPF. The LED in the switch is on when the
insert point is pre EQ.

16. INSERT ON

This locking switch activates the channel’s
INSERT IN jack, from which it applies signal to
the rest of the channel (see item [15] also). The
INSERT OUT jack is always “live,” and this
switch does not affect it. The primary use of this

switch is to select or de-select any signal proces-

sor or independent line input source which may
be plugged into INSERT IN. When the switch is
engaged, making the Insert In jack “live,” the
LED in the stitch is on.

If there is nothing plugged into the INSERT IN

jack, this switch has no effect.

Page 2-3

iary mixing bus. When the switch is in the center
(OFF) position, no signal is applied to the auxil­iary bus.

NOTE: In some applications, it is preferable to have the
PRE position be Pre-Fader & Post-EQ rather than Pre­Fader & Pre EQ. The PM4000 is equipped with internal
switches that make it easy to change the “Pre” of each
AUX send in this manner. This functional modification

can be performed on a channel-by-channel basis, and for
any or all AUX sends within each channel. Refer to the
OPTIONAL FUNCTIONS section of this manual for
additional information.

NOTE: All eight aux sends perform identical functions,

as shipped. Color coding helps associate the channel
send controls with the Aux Master LEVEL controls. If

you reset the “Pre” function for the sends of some busses,

or on some channels, it is a good idea to attach a note to

the console indicating how you have set it up.

CAUTION: Any input module may be used
as an auxiliary return. If a module is used
in this way, DO NOT assign the return to
the same auxiliary bus whose output is
feeding the signal processor which is
providing the return signal. This will
almost certainly cause feedback which
can damage circuits and/or loudspeakers.
This caution applies to Aux busses 1
through 8, and to the stereo aux busses.

Figure 2-1b. PM4000 Standard Input Module

(middle portion of module)

NOTE: A signal processor (effects device) can be set up

before it is needed, its levels adjusted using the always
active INSERT OUT signal, and then the processor can
be inserted on cue in the channel’s signal path by

pressing this switch.

17. AUX 1 - 8 (Send level & Pre/Off/Post switches)

There are 8 rotary AUX send level controls with

concentric PRE/OFF/POST switches. The switch
mutes (turns off) the send, or derives signal
before (PRE) or after (POST) the channel fader
and equalizer. The inner rotary control deter­mines how much of the selected signal source is

applied to the correspondingly numbered auxil-

18. AUX ST 1

These are two pair of concentric level controls

and switches. Depending on how you set the
outer switch on the right-hand control, they can

function as either an independent pair of Aux

sends, similar to the eight individual AUX sends,
or they can function as a single stereo Aux send

with level and balance controls.

The outer PRE/OFF/POST switch on the left­hand control set determines whether the send
is off, derives signal before the fader and
equalizer, of after them (just as with the
individual aux sends). This function affects
both “sides” of the AUX ST 1 output, whether
used for stereo or dual mono sends.

The outer switch on the right-hand control set

determines whether AUX ST 1 functions as a
stereo send (switch set to the left “PAN” posi­tion) or as a pair of mono sends (switch set to
the right “LEVEL R” position).

When the send is set for stereo mode, the inner
rotary control on the left determines the overall
LEVEL applied to the Stereo 1 L & R auxiliary

Page 2-4

mixing buses, and the inner rotary control on
the right serves to PAN that signal between the
L & R sides of that stereo pair.

When the send is set for dual mono mode, the
inner rotary control on the left sets the LEVEL

applied to the AUX ST L bus (i.e., LEVEL-L),
and the inner rotary control on the right sets
the LEVEL applied to the AUX ST R bus (i.e.,
LEVEL-R).

19. AUX ST 2

These two pair of concentric controls and
switches function just like AUX ST 1, but affect
the #2 auxiliary stereo bus pair.

Note: By setting AUX ST 1 and AUX ST 2 to dual mono

mode, you have a total of 12 independent auxiliary
mixing busses.

20. MT PRE (switch) and level meter

The channel level meter consists of 6 LEDs that

-20

display signal levels from
plus PEAK (3 dB below clipping). The meter
normally indicates the level after the EQ and the

channel fader. Engaging the METER PRE switch
causes the meter to indicate level ahead of the
fader. An LED in the switch is illuminated when
the meter is displaying pre-fader level.

21. ON switch (Channel On)

Pressing this switch turns the input channel ON,

which means the channel output is potentially

available to the 8 group mixing busses, the stereo

bus, the 8 auxiliary mixing busses, and the two

pair of stereo aux mixing busses. Engaging the

switch does not necessarily mean the switch will

be illuminated or that the channel will turn on;

muting logic may be dictating that the channel

remain off. When the channel is OFF, the feed to

the VU meter is also off, although the signal may

still be previewed with the CUE/SOLO switch

[26].

22. VCA GROUP (Assign 1 - 8)

Engaging any of these 8 locking switches enables

the corresponding VCA GROUP MASTER
FADER(s) to also control the output level of this
channel. When a VCA switch is engaged, the
LED in the switch turns on.

dB u to +6 dBu,

CAUTION: If you assign (or deassign) an
input channel to a VCA group during a
performance, the channel gain will jump
up or down unless the corresponding VCA
MASTER Fader is set precisely to the
nominal position (green LED "NOMINAL"

LED illuminated).

Figure 2-1c. PM4000 Standard Input Module

(lower portion of module)

23. MUTE (Assign 1 - 8)

Engaging any of these 8 locking switches enables
the corresponding Group MUTE MASTER

switch(es) to “kill” (turn off’) this channel. An
exception exists when the channel MUTE SAFE

switch [24] is engaged, in which case these MUTE

switches can have no effect. When a MUTE switch

is engaged, the LED in the switch turns on.

24. S (Mute safe)

The LED in this locking switch is illuminated
when the switch is engaged. When MUTE SAFE

is on, it overrides any combination of MASTER

MUTE and channel MUTE switch settings, and

Page 2-5

prevents the channel from being muted. Engag­ing this switch ensures the channel will always
be on so long as the channel ON switch is also

engaged.

25. FADER

This long-throw fader sets the level applied to the
8 group mixing busses, and the stereo bus. It also

affects any auxiliary feeds which are set to post­fader position. The Fader does not pass audio, but
instead controls a VCA through which the audio

signal flows. The channel level may, therefore,

also be controlled remotely from the 8 VCA

Master Faders [47] or the VCA/MUTE CON-

TROL connector [129] if one or more of the VCA

GROUP Assign switches [22] is engaged.

26. CUE/SOLO

The function of this switch on each input channel

will depend on the setting of the console’s Master

SOLO MODE switch [48].
If the console is set to the SOLO MODE, then

pressing this switch mutes all other input chan­nels, and only the input channel(s) whose CUE/

SOLO switch is engaged will feed the console
outputs. (This is also known as “solo in place.“)

If the console is set to the CUE MODE, the
console then has a dual-priority cue system,
designed to give the engineer maximum control
and speed when it is most important. In this
mode, pressing the channel CUE/SOLO switch
causes the channel signal to replace any master
signal in the Cue output and the Phones output.

The engineer can readily select any of 27 output
mixes (Group 1-8, Matrix 1-8, Aux Send 1-8, Aux
Stereo 1 and 2, or Stereo L & R) by pressing the
corresponding CUE switches. In most cases, once
the individual output mixes have been estab­lished, the engineer will want to listen to the

“most important output mix” during the perfor-

mance, possibly the main house feed or the vocal

group. However, should feedback occur, or should
any other condition require attention, the
PM4000 enables the engineer to instantly check

any input channel or channels by pressing their
CUE/SOLO switch(es). The input whose CUE
switch is engaged then automatically replaces the
selected output mix in the headphone and cue
outputs. The engineer can make the necessary
adjustment, and then return to monitoring the
original output mix simply by releasing the input
CUE/SOLO switch.

Pressing the CUE/SOLO switch part-way down
causes momentary contact; pressing it further
locks it down. In either case, the LED in the

switch is illuminated when the channel is being
cue’d or soloed. Although the cue signal is not

affected by the Fader or ON/off switch, it is
affected by the Input PAD, GAIN control, Filter,
channel EQ, and anything connected between the
channel’s INSERT IN and OUT jacks (if the
INSERT switch is engaged).

NOTE: Since the console operator may normally be
listening to the stereo bus or one or more group busses by
means of engaging their cue switches, the PM4000 is set

up for input cue priority. As soon as one or more input
channel cue switches are engaged, any bus cue signal
will be replaced by the input cue signal(s). Input priority
is also given to other PM4000 inputs (Aux Return cue),
not just to the input channel cue signals.

Page 2-6

2.1.2. The Stereo Input Module

The PM4000 comes with at least four stereo input
modules, located in near the master section. More of
these stereo modules can be ordered in lieu of the
monaural input modules. Their position in the main­frame is completely interchangeable with the standard
input modules (see Section 6 for details).

1S. 1 2 3 4 5 6 7 8 (ASSIGN switches)

These locking switches assign the channel output
to group mixing busses 1 through 8. The signal is
assigned as follows: the left input signal is routed
to the odd-numbered busses, and the right input
signal to the even-numbered busses. An LED
indicator in each switch turns on when the signal
is assigned to the bus. The relative level assigned
to any adjacent pair of odd and even busses
depends upon the use of the BAL/PAN switch and
control [2S].

NOTE: The stereo input modules in mainframe positions

#3 and #4 have stereo outputs that are permanently
assigned to the ST CH3 and ST CH4 busses. These
busses are routed only to the monitor module, and

permit direct monitoring of these stereo modules. Inter-

nal switches in these stereo modules actually perform the
assignment, and, if desired, you need not assign the
modules’s outputs as shipped from the factory. For that
matter, you can assign stereo modules in any mainframe

position to either the ST CH3 or ST CH4 bus by means

of these on-board selector switches. Moreover, if you do
assign the output to ST CH3 or ST CH4, you may decide
to cut internal jumpers and thereby defeat the module’s
output to any of the Group busses. If you do this, the
Group Assign switches [1S] will have no function,
although BAL/PAN [2S] will affect the feed to the ST

CH3 or ST CH4 bus. Refer to the Optional Functions in

Section 6 of this manual for details.

Figure 2-2a. PM4000 Stereo Input Module

(upper portion of module)

2S. BAL/PAN (pushbutton switch)

BAL/PAN (rotary control)
ST-L-R-L+R (concentric rotary

signal selector switch)

The locking BAL/PAN switch determines whether
the inner rotary control has any effect on the
signal or not. When the switch is engaged, the
control serves to either balance the stereo signal
between adjacent pairs of group mixing busses or
to pan the mono signal between these pairs of
busses.

The ST-L-R-L+R switch, which is concentric
with the balance/pan control, determines the

nature of the signal being fed to the group and

stereo output busses. In ST position, the left

Page 2-7

input is available at odd-numbered busses, and
the right input at even numbered busses (and, of
course, L&R in are available to the L&R stereo
bus). In L position, the right input is deactivated,
and the left input connector is available to all
group busses and the L&R sides of the stereo bus.

Similarly, in R position, the right input is avail-

able to the various busses. In L+R position, the
left and right inputs are combined to mono, and
this mono mix is then available to the various bus

outputs. (Actually, this switch also affects the

signal available to the cue and aux busses, too.)

The LED in the BAL/PAN switch is engaged

when the balance or pan function is active. When

the switch is up, the rotary control has no effect,

and a 3 dB pad is placed in line to all bus out-

puts. For a stereo pair, 3 dB of padding is the

equivalent to placing a pan control at mid posi-

tion, and thus assures that the total power

available from a pair of outputs is equal to the
power that would be available if all the signal
were panned to one output were. It means there
will be no sudden change in level if, with the pan

pot centered, you engage or disengage the BAL/

PAN switch.

3. ST (Stereo)

This locking switch assigns the channel output

directly to the stereo bus. An LED in the switch

turns on when the signal is assigned to the stereo

bus. The left and right inputs will be routed to

the corresponding left and right sides of the

stereo bus only if the adjacent, rotary signal
selector switch [2S] is set to the ST position.

4. +48V

This switch turns phantom power on and off at
the channel’s XLR input connectors. Power can be
turned on, however, only if the MASTER PHAN­TOM POWER switch is on. An LED in the switch
turns on when phantom power is being applied to
the channel input connector.

When both the Master and this switch are on,

+48 volts is applied to both pins 2 & 3 of the
channel input XLR connectors for remote power­ing of condenser microphones. Although phantom
power will not harm most dynamic and other
non-phantom powered microphones or line-level

devices, connection of an unbalanced source to

the channel input could partially short the

console’s phantom supply, cause undue loading,
and induce hum. Therefore, it is a good practice
to turn off the channel’s phantom power unless it
is actually in use.

NOTE: The console’s microphone power supply is not

intended for A-B powered microphones. External sup-

plies may be used with these devices, in which case the

console’s phantom power should be turned OFF on the
appropriate channels. The optional input transformers,
if installed, do not affect phantom power operation.

5S. GAIN

This pair of concentric rotary knobs provides
50 dB of continuously variable adjustment for the
left and right input preamplifier gain. A setting
of -70 (full clockwise rotation) provides maximum
gain for low-level mic inputs, whereas a setting of

-20 provides

minimum gain for low-level line
inputs or “hot” mics. These settings provide 30 dB
less overall gain when

30

dB pad is engaged [6].

The two controls are clutched so that you can
adjust gain simultaneously for both inputs, but
you can also reduce the gain of the left input
relative to the right if you need to compensate for
inputs which vary in level. In an “emergency”
where you run short of conventional single-

channel inputs, you can use this split gain control
to accommodate two different sources, one mic­level (right side) and one line-level (left side). Use

care, however, to avoid crosstalk if you split an

input module in this manner.

6. 30 dB (pad switch)

Engaging this pushbutton switch attenuates the

left and right input signals 30 dB and turns on an

LED in the switch. The PAD should be used in

conjunction with the GAIN controls to obtain the
precise channel sensitivity necessary for a given
source. If you’re not sure whether an input is
high line level or mic level, begin with the pad
engaged, and the GAIN controls at -20 (+10)
position. Then rotate the GAIN controls clock­wise. If you still don’t get enough level, or if the

signal is noisy with a lot of gain, then turn down
the GAIN, disengage the pad and reset the GAIN
controls as necessary.

NOTE: By adjusting the GAIN controls, you may be able

to get the same overall level with or without the pad
engaged. Listen for noise and distortion, though; if the
signal is noisy, don’t use the pad. If there is a lot of
distortion, use the pad.

7S. L-PEAK-R

This pair red LED turn on to indicate when the

signal present after the corresponding left and

right preamps is too high in level. The LEDs
trigger 3 dB below clipping, and should therefore
flash on only occasionally.

Page 2-8

This indicators measure signal from the XLRs or

from the INSERT IN jacks, whichever are active,
as well as after the equalizer. If necessary, use
the PAD or decrease the GAIN setting to prevent
the LEDs from remaining on any longer than
momentarily; otherwise excessive distortion and
insufficient fader travel will result.

With stereo input sources, listen to ensure the
stereo balance is correct. Then adjust both GAIN
controls together; if you adjust only one of the
concentric GAIN controls to eliminate PEAK
indications, you may eliminate clipping, but you
will also disrupt the stereo program balance.

8S. Ø (Phase)

This switch reverses the polarity of pins 2 and 3
of the channel’s two XLR input connectors. In
normal position (switch button up), pin 2 is the

signal high conductor, and in reverse position
(switch engaged), pin 3 is high. An LED in the

switch is illuminated when polarity is reversed.
This function, as supplied from the factory, may

help reduce feedback. However, if the two sources
feeding a single input channel are reversed in

polarity from one another, this function will not
help you. Therefore, each PM4000 stereo input
module has an optional function that causes the
Ø switch to instead reverse the polarity of only
the left input. The switch is available on the
channel’s circuit board (see the OPTIONAL
FUNCTIONS section of this manual for details).

EQUALIZER

The input channel equalizer is divided into four
bands, each with sweepable filter frequencies.
The high and low bands may be switched for a

peaking or shelving type curve, whereas the high­mid and low-mid bands are of the peaking type.
All four bands have adjustable Q, providing fully

parametric type EQ. The level (gain) is adjustable

over a range of 15 dB boost and 15 dB cut in each

band. There are actually two equalizers in the

channel, and when you adjust any of these EQ

controls, you are simultaneously affecting the left

and right sides of the channel.

9. HIGH (Peak/Shelf)

This locking switch selects peaking type EQ
(switch out) or shelving type EQ (switch en­gaged). When the switch is engaged (shelving
mode), the adjacent Q control is not operational.

Q

This rotary control adjusts the Q (the bandwidth)

of this section of the equalizer from a very narrow

band to a very broad band, with a center detent

at a Q of 1.2.

1 ~ 20 kHz

The outer concentric knob sweeps the EQ Fre­quency between 1,000 and 20,000 Hz.

-15 ~ +15 dB

The inner concentric knob adjusts the gain of the

set frequency band by plus or minus 15 dB. A
center detent is provided for unity gain.

10. HIGH-MID
Q

This rotary control adjusts the Q (the bandwidth)
of this section of the equalizer from a very narrow
band to a very broad band, with a center detent
at a Q of 1.2.

0.4 ~ 8 kHz

The outer concentric knob sweeps the EQ Fre-

quency between 400 Hz and 8,000 Hz.

-15 ~ +15 dB

The inner concentric knob adjusts the gain of the
set frequency band by plus or minus 15 dB. A
center detent is provided for unity gain.

11. LO-MID
Q

This rotary control adjusts the Q (the bandwidth)

of this section of the equalizer from a very narrow

band to a very broad band, with a center detent

at a Q of 1.2.

80Hz ~ 1.6 kHz

The outer concentric knob sweeps the EQ Fre-

quency between 80 Hz and 1,600 Hz.

-15 ~ +15 dB

The inner concentric knob adjusts the gain of the
set frequency band by plus or minus 15 dB. A
center detent is provided for unity gain.

12. LO (Peak/Shelf)

This locking switch selects peaking type EQ

(switch out) or shelving type EQ (switch en­gaged). When the switch is engaged (shelving
mode), the adjacent Q control is not operational.

Q

This rotary control adjusts the Q (the bandwidth)

of this section of the equalizer from a very narrow

band to a very broad band, with a center detent

at a Q of 1.2.

30 Hz ~ 600 Hz

The outer concentric knob sweeps the EQ Fre-

quency between 30 and 600 Hz.

-15 ~ +15 dB

The inner concentric knob adjusts the gain of
the set frequency band by plus or minus 15 dB.
A center detent is provided for unity gain.

Page 2-9

NOTE: PM3000 users will notice there is no EQ CLIP

indicator. Clipping at this stage can occur even though
the input signal is not clipping, due to boost (gain)
applied with the EQ circuitry. In the PM4000, clipping
in the equalizer is detected and shown on the PEAK
indicators [7S] adjacent to the GAIN controls.

13. EQ (In/Out switch)

This locking switch activates the channel EQ or
bypasses it completely. The EQ is active when the
switch is engaged (and the LED in it is on).
Bypass allows for A-B comparison, and absolutely
minimum signal degradation when EQ is not
needed.

14. HPF (H.P. filter in/out switch and control)

This locking switch activates the input channel
HIGH PASS FILTER or bypasses it. The filter is

active when the switch is engaged (and the LED

in it is on). This filter bypass function is indepen-

dent of the EQ section, which has its own bypass
switch.

20~400Hz

This rotary control sweeps the cutoff frequency of
a high pass filter (or "low cut" filter) from 20 Hz
to 400 Hz. The filter slope is 12 dB per octave.

Typical applications including cutting wind noise,
vocal “P” pops, stage rumble, and low frequency
leakage from adjacent instruments. You can use
higher frequency settings to reduce leakage into
mics that are primarily handling high-frequency
sources. It is a good practice to use the filter to
protect woofers from unnecessary over-excursion

due to the presence of unneeded low frequency or
sub-sonic components, especially if a microphone

is dropped or kicked. Bypass the filter (switch up)

only when you want very low frequencies, as with
an organ, drum, bass guitar, and so forth.

15. (feature number 15 is not used in this mod­ule)

16. INSERT ON

This locking switch activates the channel’s
INSERT IN jacks, from which it applies signal to
the rest of the channel. The INSERT OUT jack is
always “live,” and this switch does not affect it.
The primary use of this switch is to select or de­select any signal processor or independent line
input source which may be plugged into INSERT
IN. When the switch is engaged, making the
Insert In jack “live,” the LED in the switch is on.

If there is nothing plugged into an INSERT IN

jack, operating this switch has no effect.

Figure 2-2b. PM4000 Stereo Input Module

(middle portion of module)

NOTE: A signal processor (effects device) can be set up

before it is needed, its levels adjusted using the always
active INSERT OUT signal, and then the processor can

be inserted on cue in the channel’s signal path by

pressing this switch.

17. AUX 1 - 8 (Send level & Pre/Off/Post switches)

There are 8 rotary AUX send level controls with

concentric PRE/OFF/POST switches. The switch
mutes (turns off) the send, or derives signal

before (PRE) or after (POST) the channel fader

and equalizer. The inner rotary control deter­mines how much of the selected signal source is
applied to the correspondingly numbered auxil-

Page 2-10

iary mixing bus. When the switch is in the center
(OFF) position, no signal is applied to the auxil­iary bus.

NOTE: When the input signal select switch [2S] is set to

stereo mode, then the left input signal can be assigned to
odd-numbered aux busses, and the right input to even
numbered busses. With a mono signal-select setting, the
same mono signal is available to all aux busses.

NOTE: In some applications, it is preferable to have the
PRE position be Pre-Fader & Post-EQ rather than Pre­Fader & Pre EQ. The PM4000 is equipped with internal
switches that make it easy to change the “Pre” of each

AUX send in this manner. This functional modification

can be performed on a channel-by-channel basis, and for
any or all AUX sends within each channel. Refer to the

OPTIONAL FUNCTIONS section of this manual for

additional information.
NOTE: All eight aux sends perform identical functions,

as shipped. Color coding helps associate the channel

send controls with the Aux Master LEVEL controls. If

you reset the "Pre" function for the sends of some busses,

or on some channels, it is a good idea to attach a note to

the console indicating how you have set it up.

When the send is set for dual mono mode, the
inner rotary control on the left sets the LEVEL
applied to the AUX ST L bus (i.e., LEVEL-L),
and the inner rotary control on the right sets the
LEVEL applied to the AUX ST R bus (i.e.,
LEVEL-R); Again, depending on the input signal

selector [2S], these two controls will be assigning
either the same mono signal or the discrete left
and right input signals to the L & R sides of this
stereo aux bus.

19S.AUX ST 2

These two pair of concentric controls and

stitches function just like AUX ST 1, but affect

the #2 auxiliary stereo bus pair.

18S.

AUX ST 1

These are two pair of concentric level controls

and switches. Depending on how you set the
outer switch on the right-hand control, they can

function as either an independent pair of Aux

sends, similar to the eight individual AUX sends,
or they can function as a single stereo Aux send
with level and balance controls.

The outer PRE/OFF/POST stitch on the left­hand control set determines whether the send is
off, derives signal before the fader and equalizer,
of after them (just as with the individual aux
sends). This function affects both “sides” of the
AUX ST 1 output, whether used for stereo or dual
mono sends.

The outer switch on the right-hand control set

determines whether AUX ST 1 functions as a
stereo send (switch set to the left “BAL PAN”
position) or as a pair of mono sends (switch set to
the right “LEVEL L—LEVEL R” position).

When the send is set for stereo mode, the inner
rotary control on the left determines the overall
LEVEL applied to the Stereo 1 L & R auxiliary
mixing buses, and the inner rotary control on the
right serves to either PAN a mono signal between
the L & R sides of that stereo pair (if the input
signal selector is in one of the mono modes) or to
BALance a stereo signal across the L & R, sides of
the pair.

Figure 2-2c. PM4000 Stereo Input Module

(lower portion of module)

Page 2-11

20S.

MT PRE (switch) and L, R (level meters)

The channel level meters consist of two rows of 6
LEDs each that display the left and right signal
levels from -20 dB u to +6 dBu, plus PEAK (3 dB
below clipping). The meters normally indicate the
level after the EQ and the channel fader. Engag­ing the METER PRE switch causes the meters to
indicate level before the fader. An LED in the
switch is illuminated when the meters are

displaying pre-fader level.

21. ON switch (Channel On)

Pressing this switch turns the input channel ON,
which means the channel output is potentially

available to the 8 group mixing busses, the stereo

bus, the 8 auxiliary mixing busses, and the two

pair of stereo aux mixing busses. Engaging the
switch does not necessarily mean the switch will
be illuminated or that the channel will turn on;
muting logic may be dictating that the channel
remain off. When the channel is OFF, the feed to
the VU meter is also off, although the signal may
still be previewed with the CUE/SOLO switch

[26].

22. VCA GROUP (Assign 1 - 8)

Engaging any of these 8 locking switches enables

the corresponding VCA GROUP MASTER
FADER(s) to also control the output level of this
channel. When a VCA switch is engaged, the
LED in the switch turns on.

CAUTION: If you assign (or deassign) an
input channel to a VCA group during a
performance, the channel gain will jump

up or down unless the corresponding VCA

MASTER Fader is set precisely to the

nominal position (green LED "NOMINAL"

LED illuminated).

23. MUTE (Assign 1 - 8)

Engaging any of these 8 locking switches enables
the corresponding Group MUTE MASTER
switch(es) to "kill” (turn off) this channel. An
exception exists when the channel MUTE SAFE
switch [24] is engaged, in which case these
MUTE switches can have no effect. When a
MUTE switch is engaged, the LED in the switch
turns on.

24. S (Mute safe)

The LED in this locking switch is illuminated
when the switch is engaged. When MUTE SAFE
is on, it overrides any combination of MASTER
MUTE and channel MUTE switch settings, and
prevents the channel from being muted. Engag-

ing this switch ensures the channel will always
be on so long as the channel ON switch is also
engaged.

25. FADER

This long-throw fader sets the level applied to the

8 group mixing busses, and the stereo bus. It also
affects any auxiliary feeds which are set to post­fader position. The Fader does not pass audio, but
instead controls a pair of VCAs through which
the left and right audio signals flow. The channel
level may, therefore, also be controlled remotely
from the 8 VCA Master Faders [47] or the VCA/
MUTE CONTROL connector [129] if one or more

of the VCA GROUP Assign switches [22] is
engaged.

26. CUE/SOLO

The function of this switch on each input channel
will depend on the setting of the console’s Master
SOLO MODE switch [48].

If the console is set to the SOLO MODE, then
pressing this switch mutes all other input chan­nels, and only the input channel(s) whose CUE/

SOLO switch is engaged will feed the console
outputs. (This is also known as "solo in place.")

If the console is set to the CUE MODE, the
console then has a dual-priority cue system,
designed to give the engineer maximum control
and speed when it is most important. In this
mode, pressing the channel CUE/SOLO switch
causes the channel signal to replace any master

signal in the Cue output and the Phones output.

27. Solo Mute Defeat Switch

When the console is in SOLO mode and any of
the CUE/SOLO switches is engaged, muting
relays in all but the soloed channel(s) turn off
the other channels. When a stereo input mod­ule is used for an effects return, you may wish
to have the return signal continue to be audible

even though you are soloing another channel.
In this case, you can set the stereo input
module so that its muting relay will not be
triggered by the solo logic. Insert a small
screwdriver or a nail into this hole and press it
gently to toggle a microswitch that defeats the
solo muting for the stereo module. Should you
wish to return to normal solo muting mode, just
press the switch again.

Page 2-12

Figure 2-3a. PM4000 Master Module

(matrix section of module)

2.1.3 The Master Module (1 - 8)

These eight modules are identical, except that each

controls a differently-numbered set of Group Master,

VCA Master and Matrix Output channels.

MATRIX SECTION

28. SUB IN

This rotary control adjusts the level of the signal
from the MTRX SUB IN connector applied to the
module’s MTRX OUT. MTRX SUB IN 1 is applied
only to MTRX OUT 1, MTRX SUB IN 2 to MTRX
OUT

2,

and so forth.

29. LR (Matrix mix level controls)

These 2 rotary controls adjust the level of signal
from the left and right sides of the stereo mixing
bus applied to the module’s MTRX OUT. Signal is
available for this mix only if there something has

been assigned to the stereo bus, either directly

from the input modules’ ST switches [3], or

indirectly via the GROUP TO ST switches [40].

30. 1 2 3 4 5 6 7 8 (Matrix mix level controls)

These 8 rotary controls adjust the level of signal
from the correspondingly numbered group mixing
busses applied to the module’s MTRX OUT.
There will only be signal available, however, if
the correspondingly numbered master modules’

GROUP TO MTRX switch [41] is engaged. The

signal applied to the matrix mix is nominally

derived post-group master fader, but an internal

jumper switch in each master module permits

this to be changed to a pre-group master fader

signal.

31. MTRX MASTER

The Matrix Mix level controls [29, 30] permit a

mono mix to be derived from the eight group

busses and the stereo bus, while the SUB IN

control adds an additional signal to the mix. The

MTRX MASTER control then sets the overall

level of this 11-source mix just before it is routed

to the matrix output connector.

32. INSERT (Matrix insert)

The matrix circuit has an insert Out/In patch

point located just before its master level control.

The OUT jack is always active. If this switch is

engaged (LED illuminated), the IN jack becomes

active. Thus, engaging the INSERT switch can
insert a signal processor in the matrix channel, or

it can substitute an external line-level input
instead of the mixed matrix signal.

Page 2-13

Figure 2-3b. PM4000 Master Module

(aux send and group sections of module)

33. CUE (Matrix cue)

Pressing this switch part-way down causes
momentary contact; pressing it further locks it
down. When the CUE switch is illuminated, the
module’s matrix mix signal (post insert point, pre
MTRX MASTER) replaces any other signal in the
Cue output and the Phones output unless an

input CUE switch is engaged. (Bus cue signals

are overriden by input cue.) The MTRX CUE
signal is Mono, regardless of how many matrix
channels are cue’d.

34. ON (Matrix On)

This locking, illuminated switch turns on when
the MTRX OUT is ON. When the MTRX OUT is
turned OFF, its signal may still be previewed
with the adjacent CUE switch [33].

AUX SEND MASTER SECTION

35. LEVEL (Aux send level)

This rotary control adjusts the overall level from
the correspondingly numbered auxiliary mixing
bus to the AUX OUT connector.

36. INSERT (Aux insert)

The aux send master circuit has an insert Out/In

patch point located just before its master level
control. The OUT jack is always active. If this
switch is engaged (LED illuminated), the IN jack

becomes active. Thus, engaging the INSERT

switch can insert a signal processor in the aux
channel, or it can substitute an external line-level
input instead of the mixed aux signal.

37. CUE (Aux send cue)

Pressing this switch part-way down causes
momentary contact; pressing it further locks it

down. When the CUE switch is illuminated, the
correspondingly numbered auxiliary send re-

places any master cue signal in the Cue output

and the Phones output unless an input CUE
switch is engaged. (Bus cue signals are overriden
by input cue.) The aux cue signal is mono, regard-

less of how many aux sends are cue’d.

38. ON (Aux On)

This locking, illuminated switch turns on when
the AUX OUT is on. When the AUX OUT is
turned off, the feed to the VU meter is also off,
although the signal may still be previewed with

the adjacent CUE switch [36].

Page 2-14

GROUP SECTION

39. PAN (group to stereo bus)

This pan control is operational only when the
adjacent GROUP-TO-ST switch is engaged. It
then pans the group signal between the left and
right sides of the stereo mixing bus. The signal is
derived after the group master fader.

40. GROUP-TO-ST

Engaging this locking, illuminated switch assigns
the group bus output to the stereo bus via the
adjacent PAN control. When the switch is not
engaged (not illuminated), the group signal is not
applied to the stereo bus, but remains available
to the discrete group output connector.

41. GROUP-TO-MTRX

Engaging this locking switch assigns signal from
the module’s GROUP OUT (ahead of the Group
ON switch) to the correspondingly numbered
matrix rotary control. The switch is illuminated
when the group signal is assigned to the matrix.

NOTE: The signal derivation is preset by means of a
switch within each of the master modules. As shipped,

the group feed to the matrix comes after the Group

Master Fader. Moving the switch within each master

module changes this to a pre-Group Master Fader feed to
the matrix. Refer to Section 6 for more information on
this optional preset switch function.

an input CUE switch is engaged. (Bus cue signals
are overriden by input cue.) The Group cue signal
is mono, regardless of how many groups are
cue’d.

45. ON (Group On)

Engaging this locking, illuminated switch turns
on the GROUP OUT. When the GROUP OUT is
turned off, the feed to the VU meter is also off,
although the signal may still be previewed with
the adjacent CUE switch [44]. This switch does
not affect the group output to the matrix or the
stereo bus.

42. GROUP MASTER FADER (Group Out Fader)

This full-length fader controls the audio signal
level from the group mixing bus which is applied
to the GROUP OUT. This is an audio fader which
controls the actual mixed audio signal, not a VCA

controller.

43. INSERT (Group insert)

The group master circuit has an insert Out/In
patch point located just before its master fader.
The OUT jack is always active. If this switch is

engaged (LED illuminated), the IN jack becomes
active. Thus, engaging the INSERT switch can
insert a signal processor in the group channel, or

it can substitute an external line-level input

instead of the mixed group signal. (This could be
useful, for example, to bring in an 8-track tape
return for rough mixdown to stereo.)

44. CUE (Group cue)

Pressing this illuminated switch part-way down

causes momentary contact; pressing it further
locks it down. When the CUE switch is illumi­nated, the module’s GROUP OUT signal (pre

Group Master Fader) replaces any master signal
in the Cue output and the Phones output unless

Page 2-15

47. VCA MASTER

This fader applies a DC control voltage to any
input channels whose correspondingly-numbered
VCA group assign switch [22] is engaged. Raising

or lowering this fader will raise or lower the output
level from those assigned input modules. The end
result can be similar to using a Group Master
Fader, except that audio is not going through this
fader. Because the VCA Master is controlling the
output level of each assigned input channel, it

affects any post-fader auxiliary sends from that

channel, as well as the channel’s output to the

eight group mixing busses and to the stereo mixing

bus.

NOTE: VCA Master faders apply DC voltage to one or

more assigned input channels. The voltage applied to the
VCA (voltage controlled amplifier) in a given input
module will be the sum of the voltages from that
module’s channel fader, plus any assigned VCA Master

faders. The higher the voltage, the greater the gain

through the channel. VCA gain structure is calculated so
that when a VCA Master Fader is set so its NOMINAL

LED is on, then that Fader has no affect on any input

channel levels. The VCA Master faders should be set to

NOMINAL position when not in use so that if an input

is subsequently assigned to a VCA, there will be no
sudden change in channel level due to an added (or
subtracted) control voltage.

Figure 2-3c. PM4000 Master Module

(VCA master section of module)

VCA SECTION

46. VCA MUTE

Engaging this switch is the equivalent of setting
the VCA master fader at maximum kill.

switch is illuminated when the master fader is
muted. This affects all input channels assigned to
the correspondingly numbered VCA group. The

switch enables you to preset a VCA group level,

then mute that group until the appropriate cue.

NOTE: This is not the same as a MASTER MUTE
function because the mute groups affect all outputs from

assigned input channels, whereas this affects only post-

fader channel outputs. Since the VCAs have a cumulative

effect, a given channel’s post-fader output is muted when
ANY VCA group to which it is assigned is muted. Master
Mute and VCA Mute together provide 16 mute groups.

The

Here are some additional VCA details

If a channel Fader is set at 0 dB, and it is assigned to
a VCA Master that is set at -10 dB, then the channel
level will be -10 dB (0 + (-10) = -10).

If the channel Fader is set at -10 dB, and is assigned
to two VCA Masters, each set at -10 dB, then the
channel level will be -30 dB (-10 + (-10) + (-10) = -30).

If the channel Fader is set at +10 dB, and is assigned
to two VCA Masters, one of which is set at +10 dB, and
the other at -20 dB, then the channel level will be 0 dB
(+10 + (+10) + (-20) = 0).

When an input Fader or an assigned VCA Master
Fader is pulled all the way down to “infinite” attenua­tion position, the voltage is sensed in the input module,

and the channel on/off relay opens to completely kill the
output from the VCA. The channel ON lamp will
remain active, however, indicating that any pre-fader
channel outputs are still “live."

If the console is set to the “SLAVE” rather than the
“MASTER” mode with the rear-panel VCA SLAVE/
MASTER switch [111], then the console’s VCA MAS­TER Faders will have no effect. Instead, any DC control
signals applied to the VCA/MUTE
[129] will affect correspondingly assigned input chan­nels.

CONTROL connector

Page 2-16

2.1.4 The Stereo Master Module

This module controls the output of the stereo bus and

the two aux stereo busses.

AUX 2 STEREO SEND MASTER SECTION

48.BAL/LEVEL R and LEVEL/LEVEL L (rotary
controls)

This pair of rotary controls’ functions depends on
the setting of the BAL/LEVEL switch [49].

With the switch disengaged (not illuminated), the
upper control serves as a balance control, in­creasing the level in the left in the left output and

decreasing the right output level of the Aux 1
stereo output as the control is rotated counter-

clockwise from center, or vice-versa as it is
rotated clockwise front center position. The lower
control then serves as a master level control that

simultaneously affects both sides of the Aux 1

stereo output
With the switch engaged (illuminated), the upper

control serves as a master level control for the

mono signal feeding the Aux 1 Right output

connector, and the lower one as the master level

control for the Aux 1 Left output connector.

49. BAL/LEVEL (locking switch)

This switch determines whether the pair of

rotary controls above and below it serve as

separate level controls for the Aux 1 left and right

outputs (switch engaged and illuminated) or as
balance and level controls for the Aux 1 outputs

(switch up, LED off).

50. INSERT (Aux 1 Stereo insert)

The Aux 1 Stereo output circuit has a pair of

insert Out/In patch points (L & R) located just

before its master level and balance controls. The

OUT jacks are always active. If this switch is

engaged (LED illuminated), the L & R IN jacks

become active. Thus, engaging the INSERT

switch can insert a stereo signal processor (or a

pair of mono processors) in the aux channel, or it

can substitute an external line-level input in-

stead of the mixed aux signals.

NOTE: The Aux Stereo Sub In jacks apply signal to the

aux mix ahead of the insert point, so aux sub-in program
will be fed to the aux insert out jacks.

Figure 2-4a. PM4000 Stereo Master Module

(upper portion of module)

51. CUE (Aux 1 Stereo cue)

Pressing this switch part-way down causes

momentary contact; pressing it further locks it

down. When the CUE switch is illuminated, the

aux 1 master cue mix signal (post insert point,
pre master control) replaces any other signal in
the Cue output and the Phones output unless an

input CUE switch is engaged. (Bus cue signals

are overriden by input cue.) The aux 1 stereo cue

signal is stereo.

Page 2-17

52. ON (Aux 1Master On)

Engaging this locking, illuminated switch turns
on the Aux 1 master output. When the output is
turned off, the feed to the VU meter is also off,

although the signal may still be previewed with

the adjacent CUE switch [51].

53. AUX 2 STEREO SEND MASTER SECTION

This cluster of controls and switches functions
identically to the Aux 1 Stereo Send Master
Section [48-52], except they affect the Aux 2
Stereo Output.

STEREO MASTER SECTION

54. STEREO-TO-MTRX

Engaging this locking switch assigns signal from
the Stereo Output (ahead of the Stereo ON
switch) to all L and R rotary mix controls in the
matrix. The switch is illuminated when the stereo

signal is assigned to the matrix.

NOTE: The signal is routed to the matrix via an internal
switch in the module. The switch is preset so the feed to

the matrix comes after the Stereo Master Fader; the
switch may be moved to obtain a pre-Stereo Master

Fader feed. Refer to Section 6 for more information on

this optional function.

55. INSERT (Stereo master insert)

The Stereo master output circuit has a pair of
insert Out/In patch points (L & R) located just
before the master faders. The OUT jacks are

always active. If this switch is engaged (LED
illuminated), the L & R IN jacks become active.
Thus, engaging the INSERT switch can insert a

stereo signal processor (or a pair of mono proces-

sors) in the stereo master output, or it can substi-

tute an external line-level input instead of the

mixed stereo signals.

NOTE: The Stereo Sub In jacks apply signal to the aux

mix ahead of the insert point, so sub-in program will be

fed to the stereo

insert out jacks.

Figure 2-4b. PM4000 Stereo Master Module

(lower portion of module)

56. CUE (Stereo master cue)

Pressing this switch part-way down causes
momentary contact; pressing it further locks it
down. When the CUE switch is illuminated, the
aux 2 master cue mix signal (post insert point,
pre master control) replaces any other signal in
the Cue output and the Phones output unless an
input CUE switch is engaged. (Bus cue signals

are overriden by input cue.) The stereo master
cue signal is stereo.

57. ON (Stereo master On)

Engaging this locking, illuminated switch turns
on the stereo master output. When the output is
turned off, the feed to the VU meter is also off,

although the signal may still be previewed with

the adjacent CUE switch [56].

58. (Dual Fader)

This pair of closely-spaced faders adjusts the
level applied from the stereo mixing bus to the
stereo output connectors. The Fader knobs are
located immediately next to each other so both
can be operated in unison with a single finger. At
the same time, the two (Left and Right) knobs
may be offset somewhat and still operated to-

Page 2-18

gether, or they can be operated completely
independently if, for example, the stereo bus is
used for two discrete mono mixes.

2.1.5 The TB (Talkback) Module

Figure 2-5a. PM4000 TB Module

(upper portion of module)

59. 1 2 3 4 5 6 7 8 (TB/OSC To Group Bus Assign)

These locking switches assign the Talkback or

Oscillator signal to group mixing busses 1

through 8. An LED in each switch turns on when

the signal is assigned to the bus.

60. TB-TO-MON. B

Engaging this switch assigns the Talkback signal
to the Monitor B mix. An LED in the switch turns
on when it is assigned.

NOTE: Normally, you do not want talkback signal

assigned to monitors because if the monitoring is via
loudspeakers, this can cause feedback. Where the Moni­tor B circuit is used for remote monitoring, you may
want to assign talkback to it. This switch provides the

flexibility to handle talkback either way.

61. ST (Stereo)

This locking switch assigns the TB/OSC output
directly to stereo mixing buss. An LED in the
switch turns on when the signal is assigned.

62.

AUX 1 2 3 4 5 6 7 8

These locking switches assign the Talkback or
Oscillator signal to aux

mixing busses 1 through

8. An LED in each switch turns on when the
signal is assigned to the bus.

63.

AUX ST 1 & ST 2

These two locking switches assign the Talkback

or Oscillator signal to aux stereo mixing bus 1
(L&R) and bus 2 (L&R). An LED in each switch
turns on when the signal is assigned to the bus.
The TB or OSC signal is mono, and is assigned
equally to the left and right sides of the stereo
bus.

64. TB OUT

This locking switch turns the TB OUT connector
on and off. It affects only the feed to the VU
meter and the output of the talkback system
which appears at the TB OUT connector (the

output being derived from the TB input when the

TALKBACK ON switch is pressed, or otherwise

from the oscillator). This switch does not affect
any TB/OSC signal which may be switch-as­signed to group mixing busses 1-8, the stereo bus,

the eight aux mixing busses, or the two stereo

aux mixing busses.

65. OSC OUT

This locking switch turns the OSC OUT connec­tor on and off. It affects only the feed to the VU
meter and the output of the oscillator that
appears at the connector. It does not affect any
oscillator signal which may be switch-assigned to
group mixing busses 1-8, the stereo bus, the eight
aux mixing busses, or the two stereo aux mixing
busses.

66. OSC ON

This red LED turns on when the oscillator is

switched on. It is a reminder to turn off the

Page 2-19