Yamaha PM1800 User manual

PROFESSIONAL
AUDIO
MIXING
CONSOLE
PM
1800
OPERATING MANUAL
YAMAHA

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 pre-
sented in the "BRIEF OPERATING INSTRUCTIONS"
section. Check this and the "SPECIFICATIONS" sec-
tion, and you will see most of what you need to know.
The balance of this manual provides background in-
formation for better utilization of the console and aux-
iliary equipment.
if you would like to know more about AC power dis-
tribution and safety, grounding, balanced versus un-
balanced cables, direct boxes, and so forth, this infor-
mation is also presented. Check the TABLE OF CON-
TENTS. |
There аге internal jumpers 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 am-
biguous, we may augment it. For example, the input
channel assign switches labeled “1, 2, 3, 4, 5, 6, 7, 8”
may be accompanied by the parenthetic reference
“(group bus assign)”.
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 six
“Auxiliary Mixing Busses.” The Stereo Fader has a
single control that simultaneously adjusts the left and
right stereo bus output level, so it is a single fader (it
does have an adjacent balance control for altering the
relative output level on the left and right sides of the
stereo bus).
We have used the terms "XLR" and "XLR-type"
throughout this manual. The connectors actually used
in this console are XLBs, which are compatible with
and equivalent to the XLRs.
Particularly important information is distinguished in
this manual by the following notations:
NOTE:
A NOTE provides key information to make proce-
dures or functions clearer or easier.
CAUTION:
A CAUTION indicates special procedures or guide-
lines that must be observed to avoid damage to the
console or related equipment, or to avoid an undesir-
able result while using the console.
WARNING:
A WARNING indicates special procedures or guidelines
that must be observed to avoid injury 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 numer-
ical 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,
thefourth 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 [6]".
WARNING: TO PREVENT FIRE OR
SHOCK HAZARD, DO NOT EXPOSE
THIS АЕРНАНСЕ TO RAIN OR МОІ5-

Table of contents
PAGE SECTION TOPIC
A A HOW TO USE THIS MANUAL
A A TERMINOLOGY AND TYPOGRAPHIC CONVENTIONS
1-1 1 INTRODUCTION
2-1 2 BRIEF OPERATING INSTRUCTIONS
2-1 2.1 PM1800 FRONT PANEL FEATURES
2-2 2.1.1 Input Module
2-6 21.2 Group 1 - 4 Modules
2-10 2.1.3 Group 5 - 8 Modules
2-12 2.1.4 Stereo Module
2-15 2.1.5 COMM Module
2-18 2.1.6 The Meter Bridge
2-20 2.2 PM1800 REAR PANEL FEATURES
2-23 2.3 PW1800 POWER SUPPLY
3-1 3 PM1800 SPECIFICATIONS
3-1 3.1 GENERAL SPECIFICATIONS (PM1800)
3-4 3.2 POWER SUPPLY SPECIFICATIONS (PW1800)
3-5 3.3 INPUT CHARACTERISTICS
3-5 3.4 OUTPUT CHARACTERISTICS
3-6 3.5 PERFORMANCE GRAPHS
3-10 3.6 BLOCK DIAGRAM AND GAIN STRUCTURE DIAGRAMS
4-1 4 INSTALLATION NOTES
4-1 41 PLANNING AN INSTALLATION
4-1 4.2 POWER MAINS
4-1 4.2.1 Verify The Correct Mains Voltage
4-1 4.2.2 Ensure There Is A Good Earth Ground
4-1 4.2.3 How То Obtain А Safety Ground When Using А 2-Wire Outlet
4-2 4.2.4 Improperly Wired AC Outlets: Lifted Grounds
42 4.2.5 Improperly Wired AC Outlets: Lifted Neutral
4-3 4.2.6 AC Safety Tips
43 4.3 THEORY ОР GROUNDING
4-4 4.3.1 What is A Ground Loop, When Is It Bad, And What to Do About it
4-5 4.3.2 Balanced Lines, Unbalanced Lines, And Ground Lift Switches
4-5 4.4 AUDIO CONNECTORS AND CABLES
4-6 4.4.1 Types Of Cable To Use
4-6 4.4.2 Cable Layout
4-7 4.4.3 Balanced Versus Unbalanced Wiring
4-9 4.4.4 The Pro's And Con's Of Input Transformers
4-9 4.4.5 Noise And Losses In Low And High Impedance Lines
4-10 4.5 DIRECT BOXES
4-10 4.5.1 Passive Guitar Direct Box
4-11 4.5.2 Active Guitar Direct Box
5-1 5 GAIN STRUCTURE AND LEVELS
5-1 5.1 STANDARD OPERATING LEVELS
5-1 5.2 DYNAMIC RANGE AND HEADROOM
5-1 5.2.1 What Is Dynamic Range?
5-1 5.2.2 The Relationship Between Sound Levels And Signal Levels
5-2 5.2.3 A Discussion Of Headroom
5-2 5.24 What Happens When The Program Source Has Wider Dynamics Than The Equipment?
5-3 5.2.5 A General Approach To Setting Levels In A Sound System
5-3 5.2.6 How То Select А Headroom Value And Adjust Levels Accordingly
5-4 5.3 GAIN OVERLAP AND HEADROOM

TOPIC
OPTIONAL FUNCTIONS
REMOVING AND INSTALLING A MODULE
INPUT
CHANNEL
AUX
3
THROUGH
6
SENDS:
PRE
OR
POST
FADER
INPUT
CHANNEL
AUX
SEND
PRE
POSITION:
PRE
FADER
&
EQ
OR
PRE
FADER/POST
EQ
GROUP-TO-MATRIX:
ASSIGNED
PRE-
OR
POST-
GROUP
MASTER
FADER
METER
FUNCTION
IN
“GROUP”
POSITION:
PRE-
OR
POST-
GROUP
ON/OFF
SWITCH
INSTALLATION
OF
OPTIONAL
INPUT
TRANSFORMERS
HINTS ON CIRCUITRY FOR REMOTE CONTROL OF THE MUTE GROUPS
OPERATING HINTS AND NOTES
CONSOLE GAIN STRUCTURE
What is the Proper Gain Structure?
What Affects Gain Structure?
Establishing the Correct Input Channel Settings
Establishing the Correct Group Master Settings
Establishing the Correct Aux Send Master Settings
Establishing the Correct Mix Matrix Settings
Establishing the Correct Aux Return Settings
Channel Muting and Gain Structure
FURTHER HINTS & CONCEPTUAL NOTES
Understanding and Using the Mix Matrix
Understanding and Use of the Master Mute Function
Stereo Panning to the Eight Group Mixing Busses
INTERFACE WITH POPULAR INTERCOM SYSTEMS
RTS Intercom Systems
CLEAR-COM Intercom Systems
APPLICATIONS
GENERAL
Sound Reinforcement
Theater
Production
Post Production
Video
SETUP CONCEPTS |
Deriving a Stereo Міх From Groups 1-8
How
to
Get
4
Independent
Stereo
Mixes
or
8
Mono
Mixes
(With
Submasters)
by
Using
the
Stereo Bus, The Mix Matrix and The Input “Pan 7-8” Switches
MAINTENANCE
CLEANING THE CONSOLE
The Console and Power Supply Exterior
Power Supply Air Filter
Pots and Faders
The Console Interior
METER LAMP REPLACEMENT
WHERE TO CHECK IF THERE IS NO OUTPUT
WHAT TO DO IN CASE OF TROUBLE

List of illustrations
PAGE# FIG#
2-1 2-1.
2-6 2-2.
2-10 2-3.
2-12 2-4.
2-15 2-5.
2-19 2-6.
2-19 2-7.
2-20 2-48.
2-22 2-9.
2-23 2-10.
2-23 2-11.
3-3 3-1.
3-4 3-2.
3-6 3-3.
3-6 3-4.
3-6 3-5.
3.5.1
3-7 3-6.
3-7 3-7.
3-7 3-8.
3.5.2
3-8 3-9.
3-8 3-10.
3-8 3-11.
3.5.3
3-8 3-12.
3-8 3-13.
3-8 3-14.
3.5.4
3-9 3-15.
3-9 3-16.
3-9 3-17.
3-9 3-18
3-9 3-19
3-9 3-20.
3-10 3-21.
3-12 3-22.
4-2 4-1.
` 4-2 4-2.
4-3 4-3.
4-4 4-4.
4-5 4-5.
4-6 4-6,
4-7 4-7.
4-8 4-8.
4-10 4-9.
4-11 4-10.
TITLE (& SECTION, WHERE NECESSARY ТО DISTINGUISH ONE DRAWING FROM ANOTHER)
PM1800 INPUT MODULE
PM1800 GROUP 1 - 4 MODULES
PM1800 GROUP 5 - 8 MODULES
PM1800 STEREO MODULE
PM1800 COMM MODULE
РМ1800-16 METER BRIDGE
PM1800-24 METER BRIDGE
PM1800 REAR PANEL
MUTE CONNECTOR PIN ASSIGNMENTS
PW1800 POWER SUPPLY
PW1800 UMBILICAL CONNECTOR PIN ASSIGNMENTS
PM1800 DIMENSIONS
PW1800 DIMENSIONS
HIGH AND LOW FREQUENCY BAND EQUALIZER CHARACTERISTICS (SHELVING)
HI-MID (A) AND LO-MID (B) BAND EQUALIZER CHARACTERISTICS (PEAKING)
HIGH PASS FILTER CHARACTERISTICS
Input Channel 1 to Group Output 1 With Input Gain control @ MAX)
FREQUENCY RESPONSE
FREQUENCY vs. T.H.D.
OUTPUT LEVEL vs T.H.D.
A) PAD at 0dB
B) PAD at 20dB
C) PAD at 40 dB
Input Channel 1 to Group Output 1 With Input Gain Control @ MIN)
FREQUENCY RESPONSE
FREQUENCY vs. T.H.D.
OUTPUT LEVEL vs T.H.D.
Aux Return 4 (L) to Group Output 1)
FREQUENCY RESPONSE
OUTPUT LEVEL vs T.H.D.
FREQUENCY vs. T.H.D.
Channel 1 Input to Phones Output, With Input Pad @ 40 dB, Gain @ MIN.)
FREQUENCY RESPONSE
OUTPUT LEVEL vs T.H.D.
FREQUENCY vs. T.H.D.
CROSSTALK OF GROUP 1 INTO 3 OR 3 INTO 1 WITH INPUT PAN CONTROL AT FULL CW &
FULL CCW POSITIONS
CROSSTALK OF STEREO L INTO R OR R INTO L WITH INPUT PAN CONTROL AT FULL CW
& FULL CCW POSITIONS
CROSSTALK OF GROUP BUS 1 INTO GROUP BUSSES 2 THROUGH 8
PM1800 SIGNAL FLOW (BLOCK DIAGRAM)
PM1800 GAIN STRUCTURE
TESTING A 2-WIRE AC OUTLET
SCHEMATIC OF AN OUTLET WITH A LIFTED NEUTRAL
TESTING A 3-WIRE AC OUTLET
TYPICAL GROUND LOOPS IN SOUND SYSTEMS
AVOID USE OF AC POWER CORD GROUND ADAPTOR TO "BREAK GROUND"
CONNECTOR WIRING FOR PM1800
A) XLR-3 input or output
B) T/R/S phone plug input or output
CABLES FOR UNBALANCED AND BALANCED LINES
NOISE REJECTION IN A BALANCED LINE
PASSIVE DIRECT BOX SCHEMATIC DIAGRAM
ACTIVE DIRECT BOX SCHEMATIC DIAGRAM

TITLE (& SECTION, WHERE NECESSARY TO DISTINGUISH ONE DRAWING FROM ANOTHER)
DYNAMIC RANGE AND HEADROOM IN SOUND SYSTEMS
HEADROOM IN DIFFERENT APPLICATIONS
REMOVAL OF MODULE FROM PM1800
INTERNAL JUMPER WIRING FOR PRE OR POST FADER (& EQ) SENDS ON AUX 3 THROUGH
AUX 6 |
INTERNAL JUMPER WIRING FOR PRE-EQ АМО POST-EQ AUX SENDS (WHEN AUX 1 OR AUX
2 PRE/OFF/POST SWITCH IS SET TO “PRE,” OR AUX 3 THROUGH 6 JUMPERS ARE IN
FACTORY-WIRED “PRE” POSITION).
INTERNAL JUMPER WIRING FOR PRE- AND POST- GROUP MASTER FADER FEEDS TO MIX
MATRIX
INTERNAL JUMPER WIRING FOR GROUP METERING BEFORE AND AFTER THE GROUP
ON/OFF SWITCH
OPTIONAL INPUT TRANSFORMER INSTALLATION
BLOCK DIAGRAM OF PM1800 MIX MATRIX
BLOCK DIAGRAM OF PM1800 MASTER MUTE SYSTEM
INTERFACE OF RTS INTERCOM TO PM1800 “COMM IN”
INTERFACE OF PM1800 “TB OUT” TO RTS INTERCOM “AUDIO COUPLING” INPUT
A) For Larger, PS-30 or PS-31 Power Supply
B) For Smaller, PS-8 Power Supply
ADAPTOR CABLE FOR SPLITTING XLR-4 INPUT/OUTPUT CONNECTOR ON CLEAR-COM
IF4-4 INTERCOM INTERFACE
SYSTEM DIAGRAM WITH GROUPS 1-8 AS SUBMASTERS, AND MAIN FEED FROM STEREO
MASTER
SYSTEM DIAGRAM FOR 4 INDEPENDENT STEREO OUTPUT MIXES VIA THE STEREO BUS,
MIX MATRIX AND GROUP #7 AND #8 OUTPUTS
REPLACEMENT OF VU METER LAMPS

SECTION 1
Introduction
The PM1800 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 popular M1500 series left off, with
still more functions, a higher level of performance, and
a greater degree of versatility than ever before.
The console is available with 16, 24, 32, or 40 input
channels. There are eight group mixing busses to which
any of the input channels can be assigned. There are
also six auxiliary mixing busses to which each input
channel may be assigned by means of PRE/OFF/POST
switches (Aux 1 & 2) or jumpers (Aux 3-6) and Send
Level controls. These six busses may therefore be used
to augment the eight groups for a total of 14 audio
mixing busses, or they may be used for a combination
of foldback send (stage monitor), effects send and re-
mote mixes.
In addition to the aux and group busses, there is a
discrete stereo bus to which signal can be assigned
from any of the Group Masters. Thus, the console can
function in a sub- grouped mode with a stereo “grand
master” fader.
The PM1800 inputs are differentially balanced, and
are equipped with a three-position attenuation PAD
plus a continuously variable GAIN trim control so that
literally any mic or line level signal can be accommo-
dated with channel faders set at nominal level. Optional
input transformers may be installed internally on а
channel-by- channel basis when extra grounding iso-
lation is required. While the console has ample head-
room throughout, it is always possible to incorrectly
set controls. For this reason, the PM1800 is equipped
with level detection at several stages. “CLIP” LEDs are
provided at the input preamp. Given that the signal is
correct there, overboost in the EQ could still lead to
clipping, so another LED, “EQ CLIP,” is included after
the EQ section. Finally, if the mixed level on the stereo
bus adds up to be too high, a “PEAK” LED in the output
meters will flash on to warn of the impending danger
of clipping.
Naturally, the PM1800 is equipped with a Mix Matrix,
the feature Yamaha pioneered in professional audio
consoles. The PM1800 Mix Matrix is an 8x4 configura-
tion. That is, there are 8 possible sources that can be
mixed together into one output. Those 8 sources can
be mixed together four different ways on four different
modules. Each matrix channel accepts signals from the
eight subgroups (pre or post master fader, depending
oninternal jumpers). These 8 sources all go through
а 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.
The PM1800 has a MASTER MUTE function just like
that introduced with the PM3000. 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
1-1
sound mixing, band personnel or instrument changes,
theatrical scene changes, and so forth. If, however, it
is imperative that a certain channel never be inad-
vertently muted, or that muting temporarily be over-
ridden, the input channel’s MUTE SAFE switch can be
engaged. Muting can also be controlled remotely, via
a rear panel connector so automation is possible.
The PM1800 is equipped with four AUXiliary RETURN
channels. Each of these is a stereo return, and can
apply a stereo signal to any of the group mixing busses,
with a BAL/PAN control for relative left/right level ad-
justments. Switches also allow aux return assignment
to any of the six auxiliary send busses (for “looping”
of one effect to the next, or for adding effects to an aux
bus which is used for other than effects purposes). A
switch in each return also permits it to accept a mono
signal and to apply that signal to any of the busses; in
this case, the BAL/PAN control becomes a PAN control
for odd/even or L/R bus assignment. Of course, if
panning is not desired, the pot may be bypassed. The
returns also include CUE and ON/OFF functions. In fact,
they may be used as mono or stereo line inputs to the
console if not needed for effects returns.
An excellent feature of the PM1800 is its extensive
cue and solo capability. There is a CUE/SOLO switch
on every input channel and on the aux returns, anda
CUE switch on every auxiliary send, the group outputs,
the matrix outputs and the 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. Furthermore, there is input cue
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 perform-
ance. 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; returns will not be muted so that any
effects applicable to the input will be heard. Similarly,
if an aux return Cue/solo switch (labeled CUE) is en-
gaged, only the aux returns will be heard, and all input
channels will be muted (unless their CUE/SOLO
switches are engaged). The SOLO switch and LED flash
to signal the operator that the console is in solo mode;
in addition, the SOLO annunciator flashes or the CUE
annunciator lights up (depending on whether the SOLO
mode is selected) whenever any CUE or CUE/SOLO
switch is engaged.
There is extensive talkback and communications
capability in the PM1800, plus a useful test oscillator.
An XLR input 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 six aux send mixing 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, 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.

Accompanying the talkback and oscillator functions is
a communications input. That input will accept any mic
or line level audio signal, typically from a professional
intercom system, another console's talkback output,
or a stage manager's mic. When a signal is present, a
front panel COMM IN lightflashesto signal the operator,
who can then turn on the communications input (if de-
sired), sothe signal appears on the console headphone
and cue outputs. Thus, with COMM IN and TALKBACK,
the console operator can establish 2- way communi-
cations without having to wear an intercom headset
as well as cue headphones.
Comprehensive metering is provided with a total of
10 VU meters on the 16-channel mainframe, or 13 VU
meters on the larger mainframes (Stereo meters in-
clude peak LEDs). The meters on all consoles include
switching to monitor 23 different circuits.
PM1800 electronic performance tracks that of it's
larger brother, the highly advanced PM3000. Its stable
input preamplifiers, low noise integrated circuits, and
sophisticated design make your job easier. In fact, low
noise, wide headroom throughout, exceptionally low
distortion, and quiet controls are the hallmark of this
top quality mixing console. The specifications tell part
of the story... your ears will tell you the most important
part.
Physically, the PM1800 is as appealing as it is elec-
tronically. A special chassis and the widespread use
of structural aluminum has enabled us to significantly
reduce the console weight compared to older designs
without sacrificing any strength. A modern-looking gray
finish and subtly color coded controls set the backdrop
for the PM1800's hundreds of illuminated switches and
indicators that give it the look of a NASA control con-
sole. All illumination (except VU meters and detachable
hooded lamps) is by means of light emitting diodes, so
maintenance is greatly reduced.
The highly advanced PM1800, with its many internally
jumpered functions, provides many of the features of
custom consoles while retaining all the value and reli-
ability of a Yamaha professional console. While its
numerous internal and front panel functions may at first
intimidate the casual console operator, the PM1800 is
actually a very straightforward console to use. Anyone
who has used the PM3000 will instantly know how this
board works. In fact, if you've ever used a Yamaha
M916, M1516A, M1524 or M1532 console, you will im-
mediately feel comfortable with the PM1800. Take a
while to study the panel, read the descriptions in this
manual, and you'll find operating this console comes
as naturally as any you've encountered. And it's far
more flexible than most.
1-2

ЗЕСПОК 2
Brief operating instructions
0080
NOTE: Іп the caption of each module illustration, we
have included the Yamaha module part number in pa-
rentheses.
2.1 PM1800 FRONT PANEL FEATURES:
£ [e] CJ [е] Ez] 2) 2) E
CUE/SOLO
©
FIGURE 2-1. PM1800 INPUT MODULE (!Р1800).

2.1.1 The Input Module
1. 12345678 (Assign)
These locking gray switches assign the channel output to group mixing busses 1
through 8.
2. ON/OFF/7-8 (Switch)
A3-position rotary switch is mounted concentrically with and determines the function
of the PAN pot. When the switch is ON, the PAN pot (inner knob) affects.signal which
is assigned to odd-numbered (counterclockwise rotation) and even-numbered (clock-
wise rotation) group busses.
When the switch is OFF, no signal flows through the PAN pot, but instead can be as-
signed directly to any of the 8 group busses from the channel.
When the switch is set to 7-8 position, the PAN pot only applies signal to group busses
7 and 8 (assuming their bus assign switches are engaged). This permits the group 7
and 8 busses to serve as a convenient stereo pair. At the same time, the other six group
busses can be assigned directly from the input channel, with the full level going to any
of these assigned busses regardless of PAN pot position.
3. PAN (Pot)
This rotary control enables the channel output to be assigned between odd-numbered
(counterclockwise rotation) and even-numbered (clockwise rotation) group busses. A
center detent is provided for equal signal assignment to odd/even or left/right busses.
Center position does apply 3 dB less signal to each bus than the level obtained with full
left or right assignment so that the combined stereo signal adds up to constant power
at all PAN pot positions.
(EQUALIZER)
The input channel equalizer is divided into four bands, each with sweepable filter
frequencies. The high and low bands have shelving EQ curves, whereas the high-mid
and low-mid bands have peaking curves. The level (gain) is adjustable over a range
of 15 dB boost and 15 dB cut in each band.
4. HIGH
1.6 ~ 16 kHz
The outer concentric knob sweeps the EQ Frequency between 1,600 and 16,000 Hz.
+15 ~ —15dB
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.
5. HIGH-MID
0.8 ~ 8 kHz
The outer concentric knob sweeps the EQ Frequency between 800 and 8,000 Hz.
+15 ~ —15dB
The inner concentric knob adjusts the Gain of the set frequency band by plus ог minus
15 dB. A center detent is provided for unity gain.
6. LOW-MID
0.16 ~ 1.6 kHz
The outer concentric knob sweeps the EQ Frequency between 160 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.
7. LOW
40 ~ 400 kHz
The outer concentric knob sweeps the EQ Frequency between 40 and 400 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.
8. EQ (In/Out switch)
This locking switch activates the channel EQ (switch in) or bypasses it completely.
Bypass allows for A-B comparison, and absolutely minimum signal degradation when
EQ is not needed.
2-2