306 User s Guide
User s Guide
306
306 Preamp/Ducker
Table of Contents
1
Chapter 2 Operator Safety Summary
2
Chapter 3 Fast Setup
3
Chapter 4 Front Panel Overview
4
Chapter 5 Rear Panel Overview
6
Chapter 6 Applications
7
Chapter 7 Troubleshooting
9
Chapter 8 Specifications
11
Chapter 9 Block Diagram
12
Chapter 10 Warranty and Service
13
Chapter 11 Declaration of Conformity
15
306
Chapter 1 Introduction
Rev A, 30 April, 1999
Symetrix part number 53306-0A00
Subject to change without notice.
'1999, Symetrix, Inc. All right reserved.
Symetrix is a registered trademark of Symetrix, Inc.
Mention of third-party products is for informational
purposes only and constitutes neither an endorsement nor
a recommendation. Symetrix assumes no responsibility
with regard to the performance or use of these products.
Under copyright laws, no part of this manual may be
reproduced or transmitted in any form or by any means,
electronic or mechanical, including photocopying,
scanning, recording or by any information storage and
retrieval system, without permission, in writing, from
Symetrix, Inc.
i
6408 216th St. SW
Mountlake Terrace, WA 98043 USA
Tel (425) 778-7728
Fax (425) 778-7727
Email: [email protected]
Chapter 1
Introduction
Congratulations on your purchase of the Symetrix 306 Preamp/Ducker. Like the other units in the
Symetrix 300 series, the 306 is designed to provide extremely versatile controls within a streamlined,
half-rack sized housing. Once installed in a paging/foreground music system, the 306 offers precise
adjustments to automatically reduce the gain of a program signal when paging occurs. This allows
the page to be heard clearly, without having to compete with program material such as audio from a
CD, radio, TV or other sources.
The Symetrix 306 has a selectable mic/line page input, with phantom power available for condenser
microphones. When the mic switch position is selected, preamplification is applied to the page
microphone signal to bring it up to line level. A line-level, direct page output is also provided by
the 306, for added flexibility. The left and right program inputs and mix outputs of the 306 allow for
mono or stereo operation.
Front panel controls tailor the amount and duration of ducking, balance the mix between page and
program signals, and provide overall volume control.
Phone:
(425) 778-7728
Fax:
(425) 778-7727
Email:
[email protected]
Website:
www.symetrixaudio.com
DUCKER
PREAMP/
DUCKER
OUTPUT
THRESHOLD (dBv)
DEPTH (dB)
HOLD
RELEASE
-20
-30
2 Sec
2 Sec
306
306
We recommend that you read this guide cover-to cover. You will find the answer to most of your
questions inside. If you have technical questions beyond the scope of this manual, please contact
our Customer Service Department at:
MIX
GAIN (dB)
0
DUCK
CLIP
-40
0
-60
BYPASS
.25 Sec
4 Sec
.5 Sec
4 Sec
PAGE
PROGRAM
-20
+20
PWR
MANUFACTURED BY SYMETRIX INC., LYNNWOOD
WA, USA. THIS PRODUCT CONTAINS NO USER
SERVICABLE PARTS.
PAGE
DIRECT OUT
MIX OUTPUTS
RIGHT
PROGRAM INPUTS
LEFT
RIGHT
PAGE INPUT
POWER
INPUT
ON
MIC
CONNECT TO
SYMETRIX PS-3
OR PS-3E POWER
SUPPLY ONLY.
POWER SUPPLY ONLY.
FABRIQUÉ AUX E.-U. PAR SYMETRIX INC.,
LYNNWOOD, WA, USA. RÉFÉREZ TOUTE
RÉPARATION À UN TECHNICIEN QUALIFIÉ.
PHANTOM
LEFT
RIGHT
RIGHT
OFF
LINE
MIC/LINE
306 PREAMP/DUCKER
Front panel
Rear panel
1
Operator Safety Summary
Equipment Markings
CAUTION
RISK OF ELECTRIC SHOCK
DO NOT OPEN
TO REDUCE THE RISK OF FIRE OR
SHOCK DO NOT EXPOSE
WARNING: ELECTRIC
THIS EQUIPMENT TO RAIN OR MOISTURE
DE CHOC ELECTRIQUE
AVIS: RISQUE
NE PAS OUVRIR
SEE OWNERS MANUAL. VOIR CAHIER D’INSTRUCTIONS.
No user serviceable parts inside. Refer servicing to qualified service personnel.
Il ne se trouve a l’interieur aucune piece pourvant entre reparée l’usager.
S’adresser a un reparateur compétent.
The lightning flash with arrowhead symbol within an
equilateral triangle is intended to alert the user of the
presence of uninsulated dangerous voltage within
the product s enclosure that may be of sufficient
magnitude to constitute a risk of electric shock to
persons. The exclamation point within an equilateral
triangle is intended to alert the user of the presence of
important operating and maintenance (servicing)
instructions in the literature accompanying the product
(i.e. this manual).
Caution To prevent electric shock, do not use the
Terms
polarized plug supplied with the unit with
any extension cord, receptacle, or other
outlet unless the blades can be fully
inserted.
Several notational conventions are used in this
manual. Some paragraphs may use Note, Caution,
or Warning as a heading. Certain typefaces and
capitalization are used to identify certain words.
These are:
306
Note
Caution
Warning
CAPITALS
Boldface
2
Identifies information that needs
extra emphasis. A Note generally
supplies extra information to help
you to better use the 306.
Identifies information that, if not
heeded, may cause damage to the
306 or other equipment in your
system.
Identifies information that, if
ignored, may be hazardous to your
health or that of others.
Controls, switches or other markings
on the 306 s chassis.
Strong emphasis.
Chapter 2
Important Safety Instructions
Please read and keep these instructions. Heed
and follow all warnings and instructions.
Install in accordance with the manufacturer s
instructions.
Power Source This product is intended to
operate from a Symetrix PS-3 or PS-3E power
supply.
Grounding The chassis of this product is
grounded through the grounding conductor of
the PS-3 or PS-3E power cord. To avoid electric
shock, plug the power cord into a properly wired
receptacle before making any connections to the
product. A protective ground connection, by
way of the grounding conductor in the power
cord, is essential for safe operation. Do not defeat
the safety purpose of the grounding plug. The
grounding plug has two blades and a third
grounding prong. The third prong is provided for
your safety. When the provided plug does not fit
your outlet, consult an electrician for replacement
of the obsolete outlet.
Danger from Loss of Ground If the protective
ground connection is lost, all accessible conductive parts, including knobs and controls that may
appear to be insulated, can render an electric
shock.
Proper Power Cord Use only the power cord
and connector specified for the product and your
operating locale. Use only a cord that is in good
condition. Protect the power cord from being
walked on or pinched, particularly at the plug,
convenience receptacle, and the point where the
cord exits from the apparatus.
Operating Locatio. Do not operate this equipment under any of the following conditions:
explosive atmospheres, in wet locations, in
inclement weather, improper or unknown AC
mains voltage, or if improperly fused. Do not
install near any heat source such as radiators,
heat registers, stoves, or other apparatus
(including amplifiers) that produce heat. Unplug
this apparatus during lightning storms or when
unused for long periods of time.
Stay Out of the Box To avoid personal injury (or
worse), do not remove the product covers or
panels. Do not operate the product without the
covers and panels properly installed. Only use
accessories specified by the manufacturer. Clean
only with a damp cloth.
User-serviceable parts There are no user
serviceable parts inside the 306. In case of
failure, refer all servicing to the factory. Servicing is required when the 306 has been damaged
in any way, such as when a power supply cord or
plug is damaged, liquid has been spilled or
objects have fallen into the apparatus, the
apparatus has been exposed to rain or moisture,
does not operate normally, or has been dropped.
Chapter 3
Fast Setup
Fast First-Time Setup
¥
Set the THRESHOLD control to the 9:00 position.
¥
Set the DEPTH control to the 12:00 position.
¥
Set the HOLD and RELEASE controls to the 9:00 position.
¥
Set the MIX control to the 12:00 position.
¥
Set the GAIN control completely counterclockwise.
¥
Connect the 306 to an appropriate source of AC power, using the Symetrix PS-3 or PS-3E
power supply provided with your 306.
¥
Set the PHANTOM POWER and MIC/LINE switches (located on the back panel) to the correct
positions.
¥
Connect your audio inputs and outputs.
¥
Turn up the GAIN control until the desired volume level is reached.
¥
Now read the rest of this manual
306
This section provides simple instructions to begin using the 306. Please refer to later chapters for
detailed descriptions of product features and applications.
3
Front Panel Overview
Chapter 4
DUCKER
DEPTH (dB)
HOLD
RELEASE
-20
-30
2 Sec
2 Sec
306
PREAMP/
DUCKER
OUTPUT
THRESHOLD (dBv)
MIX
GAIN (dB)
0
DUCK
CLIP
-40
0
-60
BYPASS
.25 Sec
4 Sec
.5 Sec
4 Sec
PAGE
PROGRAM
-20
+20
PWR
Ducker Controls
DUCK LED — This LED lights to indicate that the page signal has exceeded the ducker threshold
(see THRESHOLD, below), and ducking of the program material is occurring.
THRESHOLD — This control adjusts the sensitivity of the ducker circuitry to signals at the page
input. Turning this control counterclockwise causes the ducker to be very responsive to a wide
dynamic range of page signals. This can be desirable if you want the ducker to react to page
signals that range from very quiet to very loud. Turning the THRESHOLD control clockwise causes
the ducker to only react to higher-level page signals. This can be useful in preventing unwanted,
lower-level signals from triggering the ducker.
DEPTH — TheDEPTH control governs the amount by which the program material will be decreased
(ducked) when the ducker s threshold has been exceeded. Maximum ducking occurs when this
control is set counterclockwise. The program material will then be ducked by 60dB (virtually
muted) whenever the signal at the page input exceeds the ducker s threshold. As the DEPTH
control is turned clockwise, the amount of ducking that occurs when the ducker has been triggered
decreases. When the DEPTH control is completely clockwise (bypass), no ducking will occur, even
when the ducker s threshold has been exceeded.
HOLD — This control determines the amount of time that ducking will continue at the level determined by the DEPTH control, once the page signal has dropped back below the ducking threshold.
As this control is turned clockwise, the hold time is increased. This causes the program material to
be ducked for a longer amount of time before the ducker releases and allows the program signal to
return to normal. Turning the control counterclockwise creates a shorter hold time, which causes
the ducker to release more quickly. Longer hold times contribute to overall smoothness, whereas
shorter hold times allow the program level to return to normal more quickly.
306
RELEASE — TheRELEASE control determines the amount of time that it will take for the program
material to be restored to its original ( unducked ) level once the hold time has passed. Setting
this control clockwise
causes a longer, smoother
return to normal program
Threshold Level
level. Setting this control
Page
counterclockwise allows
Input
the program level to
Level
recover more swiftly after a
page. Long release times
Hold Time
Duck Level
also contribute to an
(Depth Control)
overall smooth sound, and
shorter release times allow
for a swifter return to
normal program levels.
4
Program
Output
Level
Release Time
Output Controls
MIX — This control sets the relative volume levels of the page signal and the program material. If
the page signal is coming through too softly relative to the program material, turn this control
counterclockwise until the desired balance is achieved. If the page signal is too loud compared to
the program material, turn this control clockwise until the desired balance is achieved.
CLIP LED — This LED is a warning light, which illuminates just before clipping (distortion) occurs in
the output stage of the 306. This LED should never light, or should only flash occasionally (on
peaks in the program material or page signal). If the CLIP LED stays on, turn the GAIN control
counterclockwise until the LED extinguishes.
GAIN (dB) — TheGAIN control is the final volume adjustment. Once you have achieved the desired
balance between page signal and program material, use the GAIN control to determine the overall
output level of the 306. Turning this control clockwise increases the volume, and turning this
control counterclockwise decreases the volume. To neither add nor subtract gain at this stage, set
the GAIN control to the 12 o clock position (the unity gain position for this control).
306
POWER LED — This LED lights to indicate the presence of power at thePOWER INPUT receptacle on
the rear of the 306.
5
MANUFACTURED BY SYMETRIX INC., LYNNWOOD
WA, USA. THIS PRODUCT CONTAINS NO USER
SERVICABLE PARTS.
PAGE
DIRECT OUT
MIX OUTPUTS
RIGHT
Chapter 5
PROGRAM INPUTS
LEFT
RIGHT
PAGE INPUT
PHANTOM
LEFT
POWER
INPUT
ON
MIC
CONNECT TO
SYMETRIX PS-3
OR PS-3E POWER
SUPPLY ONLY.
POWER SUPPLY ONLY.
RIGHT
FABRIQUÉ AUX E.-U. PAR SYMETRIX INC.,
LYNNWOOD, WA, USA. RÉFÉREZ TOUTE
RÉPARATION À UN TECHNICIEN QUALIFIÉ.
OFF
LINE
MIC/LINE
RIGHT
306 PREAMP/DUCKER
Rear Panel Overview
POWER INPUT — This is a 7-pin DIN power receptacle. Connect only the Symetrix PS-3 (120V power
supply), Symetrix PS-3E (230V power supply) or Symetrix PS-3Y (power supply splitting cable for
powering two Symetrix units) to the POWER INPUT receptacle. Connect the AC power connector of
the PS-3 or PS-3E to an AC power source that is of the correct voltage and frequency, as marked on
the PS-3 or PS-3E.
PAGE DIRECT OUT — This Euroblock terminal connector provides a line-levelbalanced output of
page signal only (no program material). The balanced output terminal pins are ground, low (-) and
high (+). For unbalanced operation, use the high (+) and ground terminal pins. Do not ground the
low (-) terminal pin. This output may be used to feed paging signal to another paging system.
MIX OUTPUT (RIGHT) — This output contains paging signal combined with the right channel of the
program material, in the proportions determined by the setting of the MIX control on the front panel
of the 306. This line-level output is available at the RIGHT MIX OUTPUT Euroblock terminal connector (balanced) and at the RIGHT MIX OUTPUT RCA connector (unbalanced).
MIX OUTPUT (LEFT) — This output contains paging signal combined with the left channel of the
program material, in the proportions determined by the setting of the MIX control on the front panel
of the 306. This line-level output is available at the LEFT MIX OUTPUT Euroblock terminal connector
(balanced) and at the LEFT MIX OUTPUT RCA connector (unbalanced).
PROGRAM INPUTS (RIGHT) — Connect the right channel of your line-level program source (signal to be
ducked) to either the RIGHT PROGRAM INPUT Euroblock connector (balanced) or the RIGHT PROGRAM
INPUT RCA connector (unbalanced).
PROGRAM INPUTS (LEFT) — Connect the left channel of your line-level program source (signal to be
ducked) to either the LEFT PROGRAM INPUT Euroblock connector (balanced) or the LEFT PROGRAM
INPUT RCA connector (unbalanced).
306
PAGE INPUT — Connect the paging source (the signal that will cause ducking of program material) to
this XLR balanced input. The XLR connector is wired Pin 1 — ground, Pin 2 — high (+) and Pin 3
— low (-). Be sure to set thePHANTOM and MIC/LINE switches to the appropriate positions.
PHANTOM switch — Set this switch to the out (off) position unless your paging source is a condenser microphone which requires phantom power. If your paging source is a condenser microphone which requires phantom power, set this switch to the in (on) position.
MANUFACTURED BY SYMETRIX INC., LYNNWOOD
WA, USA. THIS PRODUCT CONTAINS NO USER
SERVICABLE PARTS.
PAGE
DIRECT OUT
MIX OUTPUTS
RIGHT
RIGHT
PAGE INPUT
PHANTOM
LEFT
ON
MIC
CONNECT TO
SYMETRIX PS-3
OR PS-3E POWER
SUPPLY ONLY.
POWER SUPPLY ONLY.
FABRIQUÉ AUX E.-U. PAR SYMETRIX INC.,
LYNNWOOD, WA, USA. RÉFÉREZ TOUTE
RÉPARATION À UN TECHNICIEN QUALIFIÉ.
TO PAGE INPUT
(LINE LEVEL) OF
ANOTHER 306
HOUSE SOUND
SYSTEM
6
PROGRAM INPUTS
LEFT
POWER
INPUT
RIGHT
RIGHT
OFF
LINE
MIC/LINE
306 PREAMP/DUCKER
MIC/LINE switch — Set this switch to the line position if your paging source is a line-level source,
such as the output of a mic preamp. If your paging source is a mic-level source, such as the output
of a microphone, set this switch to the mic position to engage the 306 s microphone preamp.
EITHER TYPE
CONNECTION
CAN BE USED
PROGRAM SOURCE
(SIGNAL THAT WILL BE DUCKED)
PAGE MICROPHONE
Chapter 6
Applications
Foreground Music with Paging
DUCKER
DEPTH (dB)
HOLD
RELEASE
-20
-30
2 Sec
2 Sec
306
PREAMP/
DUCKER
OUTPUT
THRESHOLD (dBv)
MIX
GAIN (dB)
0
DUCK
CLIP
-40
0
-60
BYPASS
.25 Sec
4 Sec
.5 Sec
PAGE
4 Sec
-20
PROGRAM
+20
PWR
This type of paging system is typically used in a restaurant or shopping mall. In these venues the
pages should be clearly heard, but the transition between paging and music should not be too
obtrusive. In this case, we recommend that you duck the background music by 10 — 20dB, and use
a longer RELEASE setting to create a smooth transition from paging back into music. Also, you
should set the threshold low enough to engage the ducker when a page is made, but high enough
that the ducker is not falsely triggered by ambient noise present at the page mic.
Foreground Music/Paging with Emergency Override
DUCKER
DEPTH (dB)
HOLD
RELEASE
-20
-30
2 Sec
2 Sec
306
PREAMP/
DUCKER
OUTPUT
THRESHOLD (dBv)
MIX
GAIN (dB)
0
DUCK
CLIP
-40
0
-60
BYPASS
.25 Sec
4 Sec
.5 Sec
PAGE
4 Sec
PROGRAM
-20
+20
PWR
If you have a foreground music or paging system that you wish to override in the case of an
emergency, you will want the ducking action to be swift and thorough. Connect the foreground
music source or line-level paging system output to the PROGRAM INPUT(S) of the 306. Connect the
emergency paging source to the PAGE INPUT and set the MIC/LINE switch to the appropriate
position. Use a low threshold setting for increased sensitivity, and set the DEPTH control completely counterclockwise for maximum ducking. We also recommend long HOLD and RELEASE
settings to prevent the program material from returning too quickly.
MIX OUTPUTS
RIGHT
PROGRAM INPUTS
LEFT
RIGHT
PAGE INPUT
PHANTOM
LEFT
ON
MIC
CONNECT TO
SYMETRIX PS-3
OR PS-3E POWER
SUPPLY ONLY.
POWER SUPPLY ONLY.
FABRIQUÉ AUX E.-U. PAR SYMETRIX INC.,
LYNNWOOD, WA, USA. RÉFÉREZ TOUTE
RÉPARATION À UN TECHNICIEN QUALIFIÉ.
RIGHT
RIGHT
EITHER TYPE
CONNECTION
CAN BE USED
TO PAGE LINE
INPUTS ON
ANOTHER 306
2ND SOUND
SYSTEM
PROGRAM SOURCE FOR 2ND ZONE
(SIGNAL THAT WILL BE DUCKED)
OFF
LINE
MIC/LINE
MANUFACTURED BY SYMETRIX INC., LYNNWOOD
WA, USA. THIS PRODUCT CONTAINS NO USER
SERVICABLE PARTS.
PAGE
DIRECT OUT
MIX OUTPUTS
RIGHT
PROGRAM INPUTS
LEFT
RIGHT
PAGE INPUT
PHANTOM
LEFT
POWER
INPUT
ON
MIC
CONNECT TO
SYMETRIX PS-3
OR PS-3E POWER
SUPPLY ONLY.
POWER SUPPLY ONLY.
FABRIQUÉ AUX E.-U. PAR SYMETRIX INC.,
LYNNWOOD, WA, USA. RÉFÉREZ TOUTE
RÉPARATION À UN TECHNICIEN QUALIFIÉ.
RIGHT
RIGHT
OFF
LINE
MIC/LINE
EITHER TYPE
CONNECTION
CAN BE USED
SET PHANTOM OFF
AND MIC/LINE TO LINE
MAIN SOUND
SYSTEM
MAIN PROGRAM SOURCE
(SIGNAL THAT WILL BE DUCKED)
PAGE MICROPHONE
Perhaps your installation requires one type of program material for one area (such as a lobby or
concourse), and a second type of program material for another area (such as a lounge), but the
same announcements need to be heard in both locations. This would call for two Symetrix 306 s.
Connect the paging source to the PAGE INPUT of the first 306, taking care to set the MIC/LINE switch
to the appropriate position. Then connect the desired program source to the Program Inputs of the
first 306. Using a short balanced, shielded cable, connect the PAGE DIRECT OUT of the first 306 to
the PAGE INPUT of the second 306. Set the MIC/LINE switch on the second 306 to the line position, and connect the appropriate program source to the PROGRAM INPUTS of the second 306.
7
306
PAGE
DIRECT OUT
POWER
INPUT
306 PREAMP/DUCKER
MANUFACTURED BY SYMETRIX INC., LYNNWOOD
WA, USA. THIS PRODUCT CONTAINS NO USER
SERVICABLE PARTS.
306 PREAMP/DUCKER
Paging in Multiple Paging Zones
To Duck or Mute Program Material without Passing Page Audio
DUCKER
DEPTH (dB)
HOLD
RELEASE
-20
-30
2 Sec
2 Sec
306
PREAMP/
DUCKER
OUTPUT
THRESHOLD (dBv)
MIX
GAIN (dB)
0
DUCK
CLIP
-40
0
-60
BYPASS
.25 Sec
4 Sec
.5 Sec
4 Sec
PAGE
PROGRAM
-20
+20
PWR
Perhaps you have a small, localized sound system that needs to be ducked when a page on a
separate paging system occurs, but you don t want the page audio to appear at the outputs of the
localized sound system. An example of this might be a museum exhibit, which has its own localized
sound system that needs to be ducked when a page occurs on the larger, museum-wide paging
system. Connect the page signal from the separate paging system to the PAGE INPUT of the 306.
Set the MIX control completely clockwise (toward Program) and the page audio will cause ducking,
but will not pass to the outputs of the 306. Adjust the amount of ducking with the Depth control.
Another example of this type of use may be seen when visiting a certain family-oriented pizza
restaurant chain. These restaurants feature a 15-minute animated show at the top of the hour,
every hour, and the rest of the time background music is played. The animated show has its own
sound system, to focus attention on the show, and the background music needs to be muted when
the animated show occurs. In this instance, you would connect the background music to the
PROGRAM INPUTS of the 306. Then, connect an audio feed from the animated show to the PAGE
INPUT of the 306, making sure to set the MIC/LINE switch to the proper position. Set the DEPTH
control completely counterclockwise, and set the MIX control completely clockwise.
306
This type of system is also used in some large airports. Each gate has its own small, localized
paging system, on which flights arriving and leaving at that gate are announced, and on which
background music may be played. A larger, separate paging system services the entire airport. To
mute the small sound systems at each gate when an announcement is made on the larger, airportwide paging system, connect a line-level local paging signal to the PROGRAM INPUT(S) of the 306.
Connect an audio feed from the larger, airport-wide paging system to the 306 s PAGE INPUT, taking
care to set the MIC/LINE switch to the correct position. Then, set the DEPTH control completely
counterclockwise, and set the MIX control completely clockwise.
8
Chapter 7
Troubleshooting
The power LED does not light:
Are you using the correct Symetrix power supply for your location? For areas with 120V AC
power, the Symetrix PS-3 is correct. For locales with 230V AC power, the Symetrix PS-3E is the
correct power supply.
Check the power supply connections at the 306 and at the AC power source.
Is the AC power source actually providing power?
If, after checking all of the above, the 306 is not powering up correctly, consult a qualified service
technician or the Symetrix factory.
There is no output signal:
Is the power LED on? If not, see above.
Is the Output Gain control set at 0 or higher?
Check input and output cables and connections.
Determine that there really is signal coming from the paging source and the program material
source, and that these signals are reaching the 306.
Is the Mic/Line switch on the Page Input set to the correct position for your paging source?
If you are connecting a condenser paging mic that does not have its own power supply to the Page
Input of the 306, is the Phantom switch set to the in position?
Try setting the Mix control to the 12 o clock position.
Is the Duck LED lit? If so, try turning the Threshold control clockwise. If the Threshold control is
set counterclockwise, the ducker could be triggered by ambient or other random noises present at
the page mic. Shorter Hold time and Release time settings may help, also.
Distortion in the output signal:
Is the Clip LED on? If it is, turn the Output Gain down.
Check your input signals. Are they overdriving any of the 306 s inputs? If so, reduce the incoming signal level.
Is the distortion occurring in both the paging signal and in the program material signal?
If the distortion is occurring only in the paging signal, check your paging source. If your paging
source is line-level, did you set the 306 s Mic/Line switch to the out position?
If the distortion is occurring only in the program material signal, then you may be feeding the 306 a
program signal that is too hot.
Are you using the correct Symetrix power supply for your locale (PS-3 for 120V AC power, PS-3E
for 230V AC power)?
No ducking is occurring:
Is the Depth control turned clockwise (bypass)? Try turning this control counterclockwise.
Is page signal reaching the 306? Do you hear the page?
9
306
Check your signal sources to make sure that the incoming signals are not already distorted before
they reach the 306.
Buzz in the output:
Check input and output connector wiring.
Check for ground loops between interconnected system equipment.
Are all system components on the same AC ground?
Noise (hiss):
Check input signal levels. The input may be too low in level. If so, boost the incoming signal.
Check the setting of the Mic/Line switch for the 306 s Page Input. If the incoming page signal is
Mic level, make sure that the Mic/Line Switch is set to the in position. If the incoming page
signal is Line level, the Mic/Line switch must be set to the out position.
Are one or both of the input signals already noisy? Listen up stream from the 306 to determine
that you are feeding it clean signals.
The 306 doesn t respond properly:
306
Consult a qualified service technician or the Symetrix factory.
10
Chapter 8
Specifications
Architects and Engineers Specifications
The 306 preamp/ducker shall provide page-over-music capability. The unit shall occupy one-half
rack space (1/2U).
The page input shall have one female XLR balanced input. The page input shall have a rear-panel
pushbutton which shall engage the preamp circuitry to provide a low-impedance microphone input,
or bypass the preamp circuitry to provide a high-impedance line input. The page input shall also
have a rear-panel pushbutton, which shall apply +15V phantom power to the page input.
The preamp/ducker shall have left-channel and right- channel line-level program inputs, accessible
by either one stereo pair of unbalanced RCA jacks or one pair of balanced Euroblock detachable
terminal connectors.
The 306 shall incorporate a priority ducking system. When audio is present at the page input, the
signal present at the program inputs shall be ducked. There shall be a threshold control, which
determines the minimum level of page audio that will trigger the ducking function. There shall also
be a duck LED, which lights to indicate that ducking is occurring. A depth control shall set the
amount of ducking that occurs. There shall be a hold control that determines the amount of time
that ducking continues, once the page signal has dropped below threshold. A release control shall
determine how quickly the program material returns to normal levels after the hold time.
The output section of the 306 shall incorporate a mix control, which determines the ratio of page
signal to program signal, and a gain control, which controls the level of signal present at the mix
outputs. There shall be a clip LED, which lights to indicate that output distortion is imminent. The
306 shall have left-channel and right-channel line-level outputs, accessible by either one stereo pair
of unbalanced RCA jacks or one pair of balanced Euroblock detachable terminal connectors.
The 306 shall also have a page direct output, which provides line-level page-only signal. This
balanced output shall have one Euroblock detachable terminal connector.
Specifications
Input/Output
Maximum Input Level
Program Input Impedance
+20dBu Balanced, +20dBu Unbalanced
>20k Ohms Balanced,
>10k Ohms Unbalanced
Input Common Mode rejection
>40dB, mic and line inputs
Microphone Phantom Power
+15V
Maximum Output Level
+26dBu Balanced (20k Ohm load)
+22dBm Balanced (600 Ohm load)
Output Impedance
400 Ohms Balanced, 200 Ohms Unbalanced
Performance Data
Page Frequency Response
50Hz to 15kHz, +0, -1 dB
Program Frequency Response
20Hz to 20kHz, +0, -1dB
Page Path THD+Noise
<.02% (Mic input to direct page output,
150 Ohm source)
Program Path THD+Noise
<.025% (+4dBu in, +4dBu out,
0dB ducking)
Output Gain
+/-20dB
Connections
Page Input
Program Inputs
Mix Outputs
Page Direct Output
Power In
Physical
Size (hwd)
Shipping Weight
Electrical
Power Requirements
XLR
RCA jacks, Euroblock
RCA jacks, Euroblock
Euroblock
7 pin DIN
˚ rack unit
1.75 x 8.5 x 6.5 in., 4.445 x 21.59 x 15.875 cm.
4.5 lbs
120V nominal, 95 to 130V AC,
50 to 60 Hz, 10 watts
230V nominal, 207 to 253V AC, 50 Hz, 10 watts
In the interest of continuous product improvement, Symetrix, Inc. reserves the right to alter, change, or modify these specifications without prior
notice.
©1999, Symetrix, Inc. All rights reserved.
11
306
The preamp/ducker shall be a Symetrix, Inc. model 306 Preamp/Ducker.
Block Diagram
Chapter 9
LEFT
BALANCED
PROGRAM IN
LEFT
BALANCED
MIX OUT
VCA
LEFT
UNBALANCED
PROGRAM IN
GAIN
LEFT
UNBALANCED
MIX OUT
RIGHT
BALANCED
PROGRAM IN
MIX
RIGHT
BALANCED
MIX OUT
VCA
RIGHT
UNBALANCED
PROGRAM IN
DUCK
RIGHT
UNBALANCED
MIX OUT
THRESHOLD
DEPTH
HOLD
CONTROL
VOLTAGE
CIRCUITRY
CLIP
RELEASE
DIRECT
PAGE
OUTPUT
PAGE
INPUT
PHANTOM
306
+V
12
MIC/LINE
Chapter 10
Warranty & Service
306 Limited Warranty
Symetrix, Inc. expressly warrants that the product will be free from defects in material and workmanship for one (1) year. Symetrix’s obligations under this warranty will be limited to repairing or
replacing, at Symetrix’s option, the part or parts of the product which prove defective in
material or workmanship within one (1) year from date of purchase, provided that the Buyer
gives Symetrix prompt notice of any defect or failure and satisfactory proof thereof. Products
may be returned by Buyer only after a Return Authorization number (RA) has been obtained
from Symetrix. Buyer will prepay all freight charges to return the product to the Symetrix
factory. Symetrix reserves the right to inspect any products which may be the subject of any
warranty claim before repair or replacement is carried out. Symetrix may, at its option, require
proof of the original date of purchase (dated copy of original retail dealer’s invoice). Final
determination of warranty coverage lies solely with Symetrix. Products repaired under warranty
will be returned freight prepaid by Symetrix via United Parcel Service (surface), to any location
within the Continental United States. At Buyer’s request the shipment may be returned via
airfreight at Buyer’s expense. Outside the Continental United States, products will be returned
freight collect.
The foregoing warranties are in lieu of all other warranties, whether oral, written, express,
implied or statutory. Symetrix, Inc. expressly disclaims any IMPLIED warranties, including
fitness for a particular purpose or merchantability. Symetrix’s warranty obligation and
buyer’s remedies hereunder are SOLELY and exclusively as stated herein.
This Symetrix product is designed and manufactured for use in professional and studio audio
systems and is not intended for other usage. With respect to products purchased by consumers for personal, family, or household use, Symetrix expressly disclaims all implied warranties, including but not limited to warranties of merchantability and fitness for a particular
purpose.
This limited warranty, with all terms, conditions and disclaimers set forth herein, shall extend
to the original purchaser and anyone who purchases the product within the specified warranty
period.
Symetrix does not authorize any third party, including any dealer or sales representative, to
assume any liability or make any additional warranties or representation regarding this product
information on behalf of Symetrix.
This limited warranty gives the buyer certain rights. You may have additional rights provided
by applicable law.
Limitation of Liability
The total liability of Symetrix on any claim, whether in contract, tort (including negligence) or
otherwise arising out of, connected with, or resulting from the manufacture, sale, delivery,
resale, repair, replacement or use of any product will not exceed the price allocable to the
product or any part thereof which gives rise to the claim. In no event will Symetrix be liable for
any incidental or consequential damages including but not limited to damage for loss of
revenue, cost of capital, claims of customers for service interruptions or failure to supply, and
costs and expenses incurred in connection with labor, overhead, transportation, installation or
removal of products or substitute facilities or supply houses.
13
306
Warranty Registration must be completed and mailed to Symetrix within thirty (30) days of the
date of purchase.
Servicing the 306
If you have determined that your 301 requires repair services and you live outside of the
United States, please contact your local Symetrix dealer or distributor for instructions on how
to obtain service. If you reside in the U.S. then proceed as follows:
Before sending anything to Symetrix, contact our Customer Service Department for a return
authorization (RA) number. The telephone number is (425) 778-7728 or email:
[email protected]
In-warranty Repairs
To get your 301 repaired under the terms of the warranty:
1.
Call us for an RA number.
2.
Pack the unit in its original packaging materials.
3.
Include your name, address, daytime telephone number, and a brief
statement of the problem.
4.
Write the RA number on the outside of the box.
5.
Ship the unit to Symetrix, freight prepaid.
We do not accept freight collect shipments.
Repairs made in-warranty will cost you only one-way freight charges. We ll prepay the return
(surface) freight.
306
If you send us your product in substandard packaging, we will charge you for factory shipping materials. If you don t have the factory packaging materials, please use an oversized
carton, wrap the unit in a plastic bag, and surround it with bubble-wrap. Pack the box full of
Styrofoam peanuts. Be sure there is enough clearance in the carton to protect the rack ears
(you wouldn t believe how many units are returned with bent ears). We will return the unit in
Symetrix packaging. Of course, if the repair is due to operator error, parts and labor will be
charged. In any event, if there are charges for the repair costs, you will pay for the return
freight. All charges will be COD unless you have made other arrangements (prepaid, Visa or
Mastercard).
Out-of-warranty Repairs
If the warranty period has passed, you ll be billed for all necessary parts, labor, packaging
materials, and freight charges. Please remember, you must call for an RA number before
sending the unit to Symetrix.
14
Chapter 11
Declaration of Conformity
Declaration of Conformity
We, Symetrix Incorporated,
6408 216th St. SW, Mountlake Terrace, Washington, USA,
declare under our sole responsibility that the product:
306 Preamp/Ducker
to which this declaration relates,
is in conformity with the following standards:
EN 60065
Safety requirements for mains operated electronic and related
apparatus for household and similar general use.
EN 55103-1
Electromagnetic compatibility - Generic emission standard
Part 1: Residential, commercial, and light industry.
EN 55103-2
Electromagnetic compatibility - Generic immunity standard
Part 1: Residential, commercial, and light industry.
The technical construction file is maintained at:
Symetrix, Inc.
6408 216th St. SW
Mountlake Terrace, WA, 98043
USA
306
The authorized representative located within the European Community is:
World Marketing Associates
P.O. Box 100
St. Austell, Cornwall, PL26 6YU, U.K.
Date of issue: April 30, 1999
Place of issue:Mountlake Terrace, Washington, USA
Authorized signature:
Dane Butcher, President, Symetrix Incorporated.
15
306
306
306
20
Symetrix, Inc.
6408 216th St. SW
Mountlake Terrace, WA, 98043
USA
Tel: (425) 778-7728
Fax: (425) 778-7727
Website: http://www.symetrixaudio.com
Email: [email protected]
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