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Online version PART 1
S R S E R I E S OW.:NER H A N D B O O K 2
Effective,from serial number 501001 onwards.
This manual includes operating and service information for all models of the SR
Series currently in production. Where differences between models exist, such as
four bus and two bus models, this is indicated in the text.
CONTENTS PAGE
Online version PART 1
INTRODUCTION ...................... Specification
Service & Guarantee Info
Electronic Performance
PANEL CONTROLS .................... Input Channel
Group Channel
Output Section
Master Section
USE OF FACILITIES ................. Input Channel
Group Channel
Output Section
Master Section
Online version PART 2 Recording with the SR range
INSTALLATION ...................... Connexions
Connexion Diagrams
Earthing
Online version PART 3 AC Supply Voltages
USER CONFIGURED OPTIONS ........... Access to Mixer Circuits
Service Notes
Phantom Power
Aux Send - Input Channel
Fx Return
Electronically Balanced O/Ps - Groups
Stereo
Online version PART 4 Mono
SERVICE INFORMATION ............... Spare Parts List
Dimensions Diagrams
Schematic Diagrams
Block Diagram
ALLEN & HEATH BRENELL LTD ISSUE 4 DEC 1988
i Control Functions
Heath PRODUCT RANG
"T
S plus series of
R
sound
reinforcement
consoles is a
development of
their highly successful S R
range.
S mixers are installed
R
in churches, leisure SR424 four group, s o and mono
centres, theatres and
concert halls around the
world, including the Purcell
Room at London's South
Bank Centre.
SR consoles are
frequently behind the
quality sound demanded
for todays professional
product launches and
commercial presentations.
SR Plus, like its
predecessor, has been
designed and built for the
rugged life led by a touring
board.
S Plus now has an
R
input pad switch operating
on both microphone and
line inputs for maximum
flexibility on gain matching
and XLR connectors are
provided for left, right and
mono outputs. These can
be balanced with the
Allen & Heath ground
sensing electronic output
balance amplifier.
SR plus stands for Sound SR12 stereo and mono outputsJ2 input channels
Reinforcement - now more
than ever.
SR8 stereo and mono outputs, 8 in zhannels :
Note: Consoles will be finished in grey
with grey side trims during 1997 -
GROUP OUTPUT STEREO OUTPUT MASTER SECTION
GROUPOUTPUTJACK R (L) MASTER OUTPUT XLRs MONO OUTPUT XLR
With optional electronically With optional electronically With optional electronically
balanced output. balanced output. balanced output.
AUX B (A) OUTPUT JACK AUX D OUTPUT JACK
AUX INPUT JACK
FX RETURN 2 (1) INPUT JACK AUX C OUTPUT JACK
TAPE INPUT JACK Dual level input connector
GROUP INSERT JACK R (L) INSERT JACK MONITOR OUTPUT JACK
Pre fade insertion point. pre fader insertion point Unbalanced stereo monitor
outout.
GROUP METER R (L) MONITOR METER
10 segment VU characteristic 10 segment Vu characteristic
display giving v~sualindication of display giving visual indication of PHANTOM POWER LED AND
group output signal levei. the selected monitor source. SWITCH
Switches the 48 volt phantom
power for the microphones on and
off.
AUXITAPE SWITCH AND
LEVEL CONTROL
With switch in aux position,
AUX B (A) LEVEL CONTROL
Auxiliary mix master output level
control.
n AUX c LEVEL CONTROL
Master output level control,
maarsr
signals from an external source
can be mixed into the group with
the level control. With switch in
the tape position, group output no
longer feeds the pan control and
the tape input is fed to the L - R
outputs via the level and pan
AUX D LEVEL CONTROL
Master output level control. :aa eux.
D
ma(I=mr
D0
1
controls, The group fader always
feeds the group output jack. FX RETURN 2 (1)
Line input signal can be added to MONO LEVEL CONTROL
the stereo mix and to aux mixes C Master control of summed L-R
and D. A level control, 2 Aux send mix (MONO) output.
controis and a pan control are 0
men0 lkvDl
10
provided, along with a PFL
MONITOR SOURCE SELECT
I
switch. eux. c
SWITCHES
Selects the signal for headphone eux. D
or control room monitoring and monm
monitor meters.
PAN CONTROL
Used to position the signal In the
stereo mix.
I Pfl
MONITOR LEVEL CONTROL &
*
z
:
GROUP PFL SWITCH Sets listening level for both
Monitors pre-fader signal to allow monitor and headphone output. 0 10
mon. !eve#
cueing of group signal
PEAK INDICATOR I PEAK INDICATOR
LED warns of imminent overload LED warns of imminent overload
(clipping]. (clipping).
GROUP FADER MASTER R (L) OUTPUT
With 10 dB boost available FADER
Controls the levei to the stereo
output and mono summing
am~lifier.
PI
HEADPHONE JACK
I
ELECTRONIC
PERFORMANCE
EQUALISER NOISE PERFORMANCE I
OdBv = 0.775 RMS 1kHz
OVU = +4dBv = 1.23 Volts RMS 8kHz. MODEL SR8 SR12 SR16 SR416 SR424
GAIN 3.5kHz continuously variable
peakidip k12dB centred at Stereo Output,
MlC IN to GROUP OUT +82dB max all inputs routed
MIC IN to UR OUT +72dB max 3.5kHz, Q=0.6
250Hz continuously variable peaW and faders closed -89dB -87dB -86dB -85dB -83dB
LlNE IN to UR OUT +50dB max
LlNE IN to GROUP OUT+6OdB max dip -+ 12dB centred at 250Hz. Group Output, all
GROUP to L/R OUT +10dB max +
LF continuously variable 12dB inputs routed and
L/R to MONO OUT +6dB with shelving characteristic at faders closed - - - -79dB -76dB
FX RETURN to UR OUT+l2dB max 80Hz.
AUXOutput -89dB -86dB -82dB -82dB -79dB
I
AUX RETURN to GROUP OUT Each model 1 shlpped ~n
s
+17dB max protective packing with the power M~crophone Input equivalent nolse -125dBm (200ohm source)
F~gures lnclude 1OdB lnput and and one owner handbook Llne enput pre-amp nolse at OdB galn -88dB.
group fader boost. wh~ch ~ncludestechnical service
INPUT GAIN CONTROL RANGE data and schematics
41 dB DlMElUSlONS mm(in)
FREQUENCYRESPONSE CONSTRUCTION MODEL SR8 SR12 SR16 SR416 SR424
Equaliser set to flat response or Steel control panel, stove enamel, Width 472 (19) 600 (24) 728 (29) 872 (35) I 128 (45)
sw~tched - 20Hz-20kHz +0,
out epoxy s~lkscreen legend
-I dB. Steel base, black flnlsh wlth
OUTPUTS wood trlms.
Max level -1-21 dBv, recommended Channel circuit boards are
Packet welght kg Ibs 20(44) 25(55) 26(58) 35(77)
load 2K ohms or more. Wlth 600 indwidual, secured to control
ohms load max level +18dBm. panel
DISTORTION Internal bussbar crrcults employ All models use power supply Mote:
AH6 MPS8P
THD typically better than 0.05% removeable harness. The supply voltage setting may be Optional soft covers are available
20Hz-20kHz at normal levels and IC op amp clrcult design wrth altered to su~t requirements ~f
local
gain settings. d~screet trans~storInput pre amp required BNC connector (to sutt lamps
rated 12-15v, 50m A, D C )
SR PLUS BLOCK SCHEMATIC
UK
Head Offices & Sales
69 Ship Street
Brighton, BN1 1AE
England
Tel: (0273) 23346
Fax: (0273) 821767
USA
5 Connair Road
Orange
Connecticut 06477
USA
Tel: (203) 795 3594
Fax: (203) 795 6814
Canada
GerrAudio Distribution Inc.
363 Adelaide Street East
Toronto, Ontario.
M5A 1N3,Canada
Tel: (416) 361-1667
Fa: (416) 868-6419
ALLEN
7
- 7
*
%
In line kith our continuous
.\-
product improvement. we
resenrep rigM to amend
the des~gn specification
and
*-t. ,--'
of equipment without notice. \ 8
'.
P
SS" < li'h
%
'-
-
-, "9
S R S E R I E S O W N E R H A N D B O O K
INTRODUCTION
SPECIFICATION
The AH0 SR SERIES is a range of versatile, economical and easy-to-use audio
mixing consoles intended for stereo and mono PA appl ications and stereol4-track
recording. The quality of design, construction and components employed will
ensure high quality performance in these applications when correctly used.
Operators are encouraged to study the contents of this handbook.
The SR SERIES includes five models as follows:
SR8 stereo and mono outputs, 8 input channels
SR12 stereo and mono outputs, 12 inp'lrt channels
SR16 stereo and mono outputs, 16 input channels
SR416 four group, stereo and mono outputs, 16 input channels
SR424 four group, stereo and mono outputs, 24 input channels
NOTE: All models use ext. power supply MPS8-P, or rack mountable RPS-1 power
supply
Construction :
1.
2.
Steel control panel, stoved enamel, epoxy si 1kscreened legend.
Steel base, black finish with wooden side trims.
3. Channel assemblies are individual and secured to control panel.
4. Internal busbar circuits employ removable harness.
5. IC op-amp circuit design featuring discrete transistor input preamp.
AC Power Requirement:
--
AHB power supplies MPS8-P, MPS9 and RPSl provide the necessary DC for the mixer
and are the only power supplies recommended for use with this product. Use of
power supplies other than the above may void the mixer warranty. All AHB power
supplies operate on the following mains voltages/frequencies -
220-2401 A.C. 50160Hz 50VA Europe
110-120V A.C. 50160Hz USA
1 0 A.C. 50160Hz 50VA Japan.
0V
Further details on mains voltages in SERVICE section.
S R S E R I E S O W N E R H A N D B O O K 4
SERVICE -GUARANTEE INFORMATION
AND
Service
There are no adjustments or a1 ignment procedures required to maintain the
performance standard of SR Series products.
To preserve the working life of the unit and its presentation, avoid the use of
chemicals, abrasives and solvents. The control panel is best cleaned with a
soft brush and a damp cloth. Faders, switches and potentiometers are lubricated
for life; the application of electrical lubricants to these parts is not
recommended.
In the event of a failure, refer the work to your Allen & Heath Sales and
Service Agent. He has the information and staff to make an effective repair,
and is authorised to make repairs under warranty. In the unlikley event the
equipment must be returned to a service agent, always include the power supply
and as much information as possible as to the nature of the problem. Always
include the model number and serial number of the unit with service queries to
ensure that accurate information is obtained.
Guarantee
SR Series ,products are made in the UK by ALLEN & HEATH BRENELL LTD, and are
guaranteed against defective parts and workmanship for a period of ONE YEAR from
the date of purchase by the original owner. Other than the work specified in
the OPTIONS Section of this handbook, no alterations to the original
construction of the product are authorised by AHB or its agents and any such
work invalidates the Guarantee.
Allen & Heath Brenell Ltd Allen & Heath Brenell (USA) Ltd
69 Ship Street 5 Connair Road
BRIGHTON BN1 1AE Orange
East Sussex Connecticut 06477
ENGLAND USA
Tel: (0273) 23346 Tel: (203) 795 3594
S R S E R I E S OWNER H A N D B O O K
ELECTRONIC PERFORMANCE
OdBv = 0.775 RMS 1kHz
OVU = t4dBv = 1.23 Volts RMS
GAIN: MIC IN to GROUP OUT t84dB max
MIC IN to L/R OUT t74dB max
LINE IN to L/R OUT t51dB max
LINE IN to GROUP OUT t61dB max
GROUP to L/R OUT t14dB max
L/R to MONO OUT +6dB
FX RETURN to L/R OUT t12dB max
TAPE IN to L/R OUT +16dB max
Figures include lOdB input and group fader bobst.
INPUT GAIN CONTROL RANGE 41dB.
FREQUENCY RESPONSE: Equaliser set to flat response or switched out -
20Hz-20kHz to, -1dB.
OUTPUTS : Max level tZldBv, recommended load 2K ohms or more.
With 600 ohms load max level i18dBm. -
DISTORTION: THD typical ly better than 0.05% 20Hz-20kHz at normal
levels and gain settings.
NOISE PERFORMANCE: RMS noise 20kHz bandwidth, ref OVU
MODEL
i Stereo Output,
a1 1 inputs routed
and faders closed -89dB -87dB -86dB -85dB -83dB
i i Group Output, a1 1
inputs routed and
faders closed - - - -79dB -76dB
i i i Aux Output -89dB -86dB -82dB -82dB -79dB
iv Microphone Input equivalent noise -125dBm (200ohm source).
v Line input pre-amp noise at OdB gain: -88dB.
SR S E R I E S OWNER HANDBOOK 6
PANEL CONTROLS
1. INPUT GAIN
Adjusts the sensitivity (gain) of the input
pre-amplifier to suit various input levels. Used
in conjunction with the PFL system to set correct
operating levels.
2. PAD SWITCH
When selected, reduces the signal level of the MIC
input by 18dB or reduces the level of the LINE
input by 12dB.
3. HIGH FREQUENCY EQUALIZER
Boosts or cuts HF content of input signal as
desired. +12dB maximum boostlcut at a corner
frequency of-8kHz with shelving characteristics.
4. HIGH MID EQUALIZER
Operates as above but with peaking characteristics
at a centre frequency of 3.5kHz. Q = 0.6
(approximately 2 octaves wide).
5. LOW MID EQUALIZER
Operates as above but at a centre frequency of
250Hz.
6. L W FREQUENCY EQUALIZER
O
Shelving type as high frequency equalizer. Corner
frequency 80Hz.
7. EQ CUT SWITCH (SR416 AND SR424 ONLY)
Instantly by-passes EQ circuit allowing direct
comparison of equal ized/unequalized signal without
the need for resetting EQ controls back to the
"flat" position.
8 AUXILIARY SEND LEVELS A,B.C,D
.
Allows the operator to create up to four different
mixes of all input sources for providing foldback,
echo or cue mixes as desired. SR Series mixers are
wired in manufacture with auxiliary sends A and B
POST-fader, and auxiliary sends C and D wired
PRE-eq. Internal selector links are provided to
allow custom formatting of all aux bus sources for
operation in the pre-eq, pre-fade or post fade
modes. (See OPERATION, OPTIONS. )
SR S E R I E S OWNER H A N D B O O K 7
9. ASSIGNMENT SWITCHES (SR416 AND SR424 ONLY)
Used in conjunction with the pan pot (10) to route
a selected input channel to subgroups 1-4 or
directly to the L/R masters as desired.
1 . PAN POT
0
Positions input signal in the stereo mix. Also
assists in routing signals to subgroups 1-4 and
permits panning of signal between groups if
desired. (See Assignment Switches. )
11. PFL SWITCH
Allows operator to monitor channel levels prior to
the fader, regardless of fader level or channel
mute status. Us2d with input gain control (1) and
peak indicator (13) to accurately set input signal
levels and provide checks of overall signal
quality.
12. MUTE SWITCH (SR416 AND SR424 ONLY)
Cancels or "mutes" selected input channel after the
fader. Also mutes signal to any aux send controls
which are set to derive their signal from the fader
output.
13. PEAK INDICATOR LED
This LED indicator flashes a warning of imminent
overload distortion (clipping ) when the channel
level is too high. Illuminates 3dB before the
onset of actual channel clipping and is affected by
INPUT GAIN ( 1 ) , and EQ (3-6) and CHANNEL FADER ( 14)
.
settings.
1 . CHANNEL FADER
4
Controls level of input channel to selected groups
and any POST fader aux sends. The fader marking
"0" is normal operating position, indicating unity
gain between input and output sections. There is
an extra lOdB boost available at the fader which is
obtained by raising the fader to its full up
position.
15. SCRIBBLE PATCH
Provided to permit identification of input
programme source.
S R S E R I E S OWNER H A N D B O O K
GROUP CHANNELS
1. GROUP METER
The group meter is a 1 segment LED display which
0
gives a visual indication of the group signal level
after the fader.
AUX/TAPE SELECT SWITCH AND CONTROL
With this switch in the UP (aux) position, signals
from an external source can be mixed into the group
using the return level control. With the switch in
the DOWN (tape) position, the fader is disconnected
from the panpot and the level control mixes the
external signal to the L/R masters via the panpot.
Used in this mode to monitor previously recorded
tracks during overdubs. It should be noted that
whilst the signal from the group fader is
disconnected from the panpot in this mode, the
signal from the fader to the group output jack is
unaffected and operates normally.
3. GROUP PFL BUTTON
Operates in the same fashion as the channel PFL
button but reads pre-fader level of group.
4. GROUP PEAK INDICATOR
This LED indicator flashes a warning of imminent
group overload distort ion (cl ipping) when the group
level is too high. Illuminates 3dB before the
onset of cl ipping distortion. Operates PRE fader
and is affected by the level and number of input
channels assigned to the group.
5. GROUP FADER
Determines the level of the signal from the group
to the L/R outputs, or to a tape track when
recording. Normal operating position "OM, however
a lOdB boost is available by raising the group
fader full up.
6. SCRIBBLE PATCH
SEE "Scribble Patch", INPUT channel.
SR S E R I E S OWNER HANDBOOK 9
OUTPUT SECTION
MoNwom L I
Morulfom q 1i 1. L/R MONITOR METERS
These mu1 t ipurpose meters monitor the L/R output
levels of the mixer and four other signal sources
as well. VU characteristics with 3dB resolution.
Range from -21 to +6 VU with 0 VU equal to 1.23
Volts RMS (t4dBv).
2. AUX A/(AUX B) LEVEL CONTROLS
The master output level controls for auxiliary
mixes A and B.
3. FX RETURNS 1 AND (2)
These identical- sections allow two line level
signals (eg the outputs from 2 effects devices) to
be added to the stereo mix and to aux mixes C and
D. Each has a level control performing the same
function as an additional channel input fader,
mixing the effects signal to the main outputs via a
PANPOT to position the signal in the stereo mix.
Two send controls are also provided so that the FX
signal can be mixed to the performers headphone or
hr. -cum 1 hr. mtum O stage monitoring system.
4. PEAK INDICATOR LED
Operates as other peak indicators described in this
handbook.
5. MASTER LEFT/ (RIGHT) OUTPUT FADERS
Control the final output level of the stereo mix
and provides signal to the MONO summing amplifier.
SR S E R I E S OWNER H A N D B O O K 10
-
MA!
1. PHANTOM POWER SWITCH AND LED
Turns 48 Volt phantom power "on" or ll~ffll.
Illuminated LED indicates "on" status.
2. MASTER OUTPUT LEVELS AUX C AND D
Control the final output level o f auxiliary mix
buses C and D.
3. MONITOR SOURCE SELECT SWITCHES/MONITOR LEVEL
This section selects the signal available for
headphone or control room monitoring via the jack
socket on the top panel. The MONITOR LEVEL control
directly beneath the switch assembly determines
listening level for both MONITOR and HEADPHONE
outputs.
4. MONO LEVEL CONTROL
Determines the final output level of the summed L/R
mix.
5. HEADPHONE JACK SOCKET
Use the headphone output to check the quality of
the mixer outputs when a suitable pair of monitor
speakers is not available.
S R S E R I E S O W N E R H A N D B O O K
USE OF FACILITIES
-- CHANNEL
THE INPUT
The input channel accepts a balanced or unbalanced input signal from a
microphone, direct box or a line level source such as the output of a
synthesiser, or external signal processing device such as a digital delay line,
reverb, etc.
SR range products are factory wired for the 48 volt phantom powering o f
condenser microphones. The supply is present at XLR pins 2 and 3. Power
supplies MPS8-P, MPS9 and RPSl provide the necessary voltage. The master
phantom power pushbutton switch and power on indicator LED are located at the
top of the master section. NOTE: When using phantom power it is important to
avoid connecting an UNBALANCED signal source to a MICROPHONE input without
having first, disconnected the phantom power source from that input. This is
accomplished by removing the phantom power internal link from the channel, or
switching the phantom power OFF. (See OPTIONS section.)
Input Gain Control
The input gain control amplifies or attenuates incoming microphone or line level
signals depending on which source is selected for use. Control range is t21 to
t62 (mic) and -ldB to t40dB (line).
Input - Switch
Pad
On occasion, situations may arise where high level signal sources (a live kick
drum, or some drum machines and synths) overload the input channel, even though
the input gain control is set at minimum. Depressing the input pad pushbutton
attenuates (or reduces) the incoming MIC signal level by 18dB and the LINE
signal level by 12dB before those signals reach the input gain control Should
this amount of attenuation prove to be excessive, the input gain control can
then be raised to bring the signal level back up to unity gain-. The PFL system
can be very helpful here, and should always be employed when attempting to set
channels up to the proper operating levels.
Channel Insert Jack
Located between the input XLR and the input gain control, this jack socket
a1 lows access to the signal path at a point immediately AFTER the input pre-amp,
and BEFORE the equalizer section. This is a convenient place to "insertI1 into
the signal path an external signal processing device such as a compressor,
limiter, or graphidparametric equalizer. It is also handy when you wish to put
a certain effect on just one channel without tying up an entire auxiliary mix
bus to do so.
S R S E R I E S OWNER H A N D B O O K 12
Use of a channel insert jack requires a cable consisting of 1 "stereo"
(ring/tip/sleeve) 1/4" phone plug wired to two "mono" (tip/sleeve) 114" phone
plugs as shown in the diagram below. When the stereo plug is plugged into the
insert jack, the mono plug wired to the ring of the stereo plug becomes the
send, or input to the processing device, and the ring becomes the return from
the output of the device.
. .-. - .---- .-..
.
I -.
1- u RETURN
4 .. W
L .
R
, . OV
L ..
SEND
figure 1. Insert Cable Assy.
S R S E R I E S O W N E R H A N D B O O K 13
Equal izer
The four band, fixed frequency equalizer section (the channel EQ) a1 lows you to
alter the tone and harmonic balance of the signal in the channel. You can also
filter out unwanted high frequency noise (hiss) or low frequency noise (rumble)
and compensate for deficiencies in older microphones or problems with your
acoustic environment.
- High Frequency Equalizer
The
This control either boosts or cuts the high frequency content of the signal
source by up to 12dB at 8kHz, having progressively less effect at frequencies
below 8kHz. This is known as a "shelving" type equalizer. At its centre
"zero" position, the control has a "flat" response and therefore no effect on
-
the high frequency signal content.
-- Frequency Equalizer
The Low
This control operates as the high frequency equalizer, but boosts or cuts those
frequencies BELOW 80Hz. This is also a shelving type equalizer; and like the
high frequency control, when set to its center "zero" position, it has no effect
on the low frequency signal content.
- High Mid/Low - Equalizers
The Mid
These equalizers operate over the middle of the frequency range centred at
3.5kHz and 250Hz respectively. These controls provide up to 12dB of boost or
cut at the specified frequencies. The mid equalizers operate both above AND
below the centre frequencies with a range of approximately 2 octaves. This
means that boosting the high mid equalizer at 3.5kHz affects not only 3.5kHz but
also frequencies as low as 1.5kHz and as high as SkHz, but to a lesser degree.
This is known as a "peaking" .type equalizer. As with the other EQ controls,
these have no effect on the signal when set to the centre flat position.
-EQ - Switch
The Cut (SR416 and SR424 only)
This allows you to instantly by-pass the EQ circuit, producing a flat response
from the channel without having to reset the controls back to their zero
pos iton. This switch is useful for making A/B comparisons of the
equalized/unequalized signal, or it can be used to "program" a certain EQ
setting for use as a special effect when needed. (Eg: a vocal "robot" eq.)
Channe1 Auxi 1 i ary Sends
Each S input channel features 4 auxiliary send controls. These controls feed
R
auxiliary masters A , B y C, and D and allow the user to create four additional
mixes of the signal sources fed to the mixer. These mixes are generally used as
feeds to external FX devices, as foldback mixes to an on-stage monitor system,
or as a cue mix for performers' headphones (cans) in recording applications.
S R S E R I E S O W N E R H A N D B O O K
- A and B are POST fader feeds to the aux A and B mixes. Their operation is
Aux
depeFdeX on the level of channel fader and will change proportionally with
fader movements and will be cut off when the mute switch (on four group models)
is activated. For this reason, these mixes are used as feeds to external FX
devices.
Aux C and D are PRE-EQ feeds to the aux C and D mixes. These mixes are
=ff>cted b7 channel EQ settings, mute status or fader position and are used as
feeds to an on-stage monitoring system. It should be noted that whilst these
mixes are not affected by changes in the EQ settings, they ARE affected by
changes made at the input gain control, and changes made there'will require that
a proportional change be made at the aux send.
SR Series mixers have been wired in this configuration in manufacture. However,
provision has been made within the mixer which allow the user to choose the
point in the channel circuit from which the aux level control derives its
source. Three choise are available - PRE-EQ, PRE-FADER, (but POST-EQ), and
POST-FADER. For further information, see OPTIONS section.
Pan Pot
--
An input signal can be placed anywhere in the stereo image by turning the PANPOT
to the right or left. Models which employ subgrouping also use the PANPOT for
routing input channels to specific groups or tracks if recording. When routing
input channels, turning the PANPOT full left routes to ODD numbered groups, and
turning full right routes to EVEN numbered groups,
S R SERIES O W N E R HANDBOOK 15
Channel Routing (SR416 and SR424 only)
Two pushbutton switches are provided for the purpose of input channel routing.
The bottom button L-R/1-4 routes the selected input channel to the main L/R
output when DEPRESSED. When this button is in the UP position, the channel
signal is routed to the GROUPS. Pairs of groups are selected by the top switch
1-2/3-4. With both switches in the UP position, the channel signal is routed to
groups 1 and 2. Depressing the 1-213-4 switch routes the channel signal to
groups 3 and 4 To route a channel to a single specific group, all that is
.
necessary is to select the proper pair of groups (1-2or 3-4) and then turn the
panpot. To route to ODD numbered groups, pan full LEFT. To route to EVEN
numbered groups, pan full RIGHT. (See PANPOT, GROUP CHANNELS. )
- Button (Pre-Fader Listen)
PFL .
Operates as the name implies. Depressing the PFL allows you to listen to the
signal of an individual channel in the control room monitors or in headphones
without the need for raising the channel fader. The PFL system always takes its
signal from the point immediately AFTER the EQ section, but BEFORE the fader,
which makes it handy for making signal level and quality checks before bringing
that channel up into the mix. It is used in conjunction with the MASTER PFL
PUSHBUTTON located at the far right of the mixer. Mhen the MASTER PFL button is
depressed, the monitor and headphone outputs switch over to "listen" to the PFL
bus, and the signal level of the selected channel is displayed on the L/R
monitor meters simultaneously.
Mute Button (SR416 and SR424 only)
When depressed, mutes or "cancels" the signal from the channel AFTER the channel
fader. Also cancels signal going to any auxiliary mixes which are set to derive
their signal post fader. (Aux A and aux B unless others have been selected.
See OPTIONS. )
Panpot
An input signal can be placed anywhere in the stereo image by turning the PANPOT
to the right or left. Models which employ subgrouping also use the PANPOT for
routing input channels to specific groups or tracks if recording. When routing
input channels, turning the PANPOT full left routes to ODD numbered groups, and
turning full right routes to EVEN numbered groups.
Peak Indicator -
LED
This provides a visual warning that the input signal is approaching overload
distortion (clipping). This can be caused by the use of too much input gain, or
excessive equal izer boost, especial ly at lower frequencies. An i 1 luminated peak
indicator is a cue to you to check the channels operating level via the PFL
system and make the proper adjustments.
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Channel Fader
Used to alter the level of an individual channel in the mix. Normal operating
level is the "0" position; however, an extra 10dB boost can be obtained by
raising the fader full up. Also provides signal feed to auxiliary mix controls
A and B or other if selected. (See OPTIONS.)
Scribble Patch
This space provided for channel identification. Use with grease pencil or other
easily erasible marker to avoid permanent damage to the mixer finish. Use of
masking or duct tape may damage the silkscreened mixer legend, particularly if
left on for long periods of time.
S R S E R I E S OWNER H A N D B O O K 17
GROUP CHANNELS (SR416 and SR424 only)
Use of the group channels allows you to control the level of any number of input
channels simultaneously. This is extremely helpful in situations where the
balance between individual channels is important. For example, let us say that
after having established a tight balance between four or more vocal channels,
the need suddenly arises to turn the vocals up or down overall. Attempting to
change each channel by the same amount is a difficult task at best, and the end
result is likely to be a big mess where your nice, tight mix was a minute ago,
and your carefully established balance ruined. Mixing situations which require
the operation to be done quickly AND accurately complicate matters further. By
assigning the vocal channels to a group, you can adjust the overall vocal level
quickly and easily whilst preserving the balance between channels assigned to
the group. Any number of similar input sources are likely candidates for
grouping. Besides vocals, drums, keys, horns-, etc are easier to keep in control
when they are assigned to a group.
- Group Meter
The
The group meter is a 1 segment LED display which provides a visual indication
0
of the group output level AFTER the fader, in 3dB steps from -12dB to +6dB. It
is a VU (average) responding meter with the "0" position indicating a group
output level of OVU or t4dBv (1.23~ RMS).
Aux/Tape Level Control (SR416 and SR424 only)
There may be times when it will be necessary to add signals from an external
source to the group signal without using a full input channel. This could be
taped accompaniment, or pre-recorded sound effects. Regardless of the
application, whenever additional audio signals must be combined with the signal
of a particular group, it can be done via the aux return. To accomplish this,
bring the extra signal into the mixer using the 114" jack socket labelled AUX
IN/TAPE IN. Ensure that the AUX/TAPE switch is in the UP (Aux) position. Your
signal can now be mixed into the group in any amount you desire using the return
level control. The return level control has another function when the button is
depressed to select the tape mode. When recording, the track outputs are
brought to the AUX/TAPE jacks and when the button is pressed the group fader is
disconnected from the panpot (and therefore the L/R outputs) and is replaced
with the signal from the tape track. It should be noted that this does not
disconnect the fader from the group output jack, allowing additional tracks to
be recorded from a group while that group is monitoring other tracks. More on
this in RECORDING WITH SR.
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OUTPUT SECTION
~ e f t / ~ i ~ h t / torn Meters
~o i
Operate as the group meters in every respect, but will also read other sources
as selected by the MONITOR SOURCE select switch (aux C, aux D, mono output, or
PFL. )
- Masters - - - B
Aux A and
These controls determine the output level of auxiliary mixes A and B. Generally
used as FX sends and should be set at around the "5" position for best operating
results. Individual input aux send controls should be set at about position "6"
to "9".
- Returns
FX 1 and
--- 2
By use of the control marked "level" these inputs can be used to bring signals
from external FX devices back into the stereo mix and also permits a portion of
the FX signal to be returned to auxiliary mix buses C and D by using the
controls provided for this purpose. The FX signal can be mixed to the aux buses
independently of the amount of signal mixed to the L/R outputs; however,
internal links are provided in the FX return circuits to enable these controls
to take their signal AFTER the level control allowing the FX signal to be mixed
to the aux buses in the same proportion as that which is mixed to the L/R
outputs. (See OPTIONS.) A PAN control is also provided so that the FX signal
can be placed within the stereo image as desired. The FX return jack is
configured to provide either unity return gain or +12dB return gain. For low
level (-lOdB) devices, the return plug should be inserted all the way into the
jack socket: this. provides 12dB extra gain. For high level devices, insert the
plug half way into the FX return jack to provide unity gain. Use the FX PFL
switch to determine the proper position if not certain. Alternatively, use a
stereo jack plug and connect the input signal to the ring contact.
- Return - Switch
FX PFL
Depress this switch to listen to the outputs of the FX devices. Should be used
for the purpose of verifying level and sonic quality of the FX signal and for
setting delay times, etc prior to bringing them up into the mix. (See PFL -
INPUT CHANNEL. )
- Indicator LED
Peak
Warns of imminent overload distortion (clipping) when the signal level of the
L/R outputs gets too high and tells you to reduce the level of the mix. The
indication is of the pre LIR output fader signal level.
LfR Output Faders
Controls the final output level of the stereo mix to the L/R output jacks and
the mono summing amplifier.
S R SERIES OWNER HANDBOOK 19
MASTER SECTION
Phantom Power Switch
Connects 48 volt phantom power to all mic inputs. LED illuminates to indicate
phantom power selected. Please consult INPUT CHANNEL operation section for
details and cautions regarding the use of phantom power. Also refer to OPTIONS
section for information on the method of disconnecting phantom power from
individual mic inputs.
Aux C/Aux
--- D Masters Level Controls
These controls determine the level o f the auxiliary mix outputs C and D. Output
level of these mixes can be read on the L/R MONITOR meters by pressing the
appropriate button in the MONITOR SELECT section.
-Output Level Control
Mono
Determines the level of the MONO OUTPUT. This is an especially useful feature
as it allows your PA system to be driven from the MONO OUTPUT which frees up the
L/R output jacks to a1 low simultaneous stereo recording. (See CONNEXION
DIAGRAM - SOUND REINFORCEMENT.)
Monitor Source Select SwitchesIMonitor Level
The four pushbutton switches in the master section allow you to monitor the
mixer functions both audibly and visually, with the MONITOR LEVEL control
governing the listening level to both the MONITOR OUTPUT and the HEADPHONES as
we1 1,
When all the switches are in .the UP position, the monitor meters display the
stereo output level of the mixer. To monitor other mixer functions, select the
appropriate pushbutton and when it is pressed, the meters will switch over to
display that function in mono, with the exception of the PFL button. When this
button is pressed, no level is displayed unless a channel, group, or FX PFL
button is pressed as well. Essentially, what the PFL button in the master
section does is PREPARE the PFL system to receive signals from other areas of
the mixer.
Monitor Select Priority
When using the monitor section, it should be noted that the lowest button
pressed takes priority over the others. For example, when PFL is selected it
will override all other monitor functions. When mono is selected, it overrides
the aux buttons but not PFL, and so on. Remember that the lowest button pressed
is the source you are listening to.
Monitor Level Control
Located beneath the monitor select switchbank, this control determines the level
of both the monitor AND headphone outputs.
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Headphone Jack Socket
Used to drive a pair of stereo headphones having an impedance of 8-600 ohms.
Headphone signal always fol lows signal source selected at MONITOR SELECT
switchbank.
S R S E R I E S OWNER H A N D B O O K 21
RECORDING --
W SR
M
I
USE OF GROUP CHANNELS (SR416 and SR424 only)
Connection -Groups - Recorder
from to
This should be done as shown in the multitrack recording diagrams, using the
four group outs to a 4 track recorder, and four replays to groups auxltape.
GROUP 1 TRACKS 1
GROUP 2 TRACKS 2
GROUP 3 TRACKS 3
GROUP 4 TRACKS 4
The operating level is OVu - +4dBv - 1.23 volts.
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