Rocktron HUSH IICX Rack Effects User manual

Rocktron HUSH IICX Rack Effects User manual
 HUSH исх“
STEREO SINGLE-ENDED NOISE REDUCTION SYSTEM
… (OWNER'S MANUAL) J
May be covered by one or more of the
following: U.S. Patents #4538297,
4647876, 4696044, 4745309,
4881047, 4893099.
Other patents pending.
Foreign patents pending.
HUSH
SYSTEMS]
INTRODUCTION:
The Hush Systems HUSH IICX™ is a rackmount single-ended noise reduction unit, providing the
versatility of a two channel package of Hush Systems’ HUSH II™, Single-ended noise reduction requires
that the audio signal pass through the system only once to eliminate noise. The HUSH HCX™ will solve
virtually ANY noise problem.
This operating manual will introduce you tothe HUSH HCX™ and its various functions. After reading
this manual carefully, keep it for future reference.
PRECAUTIONS:
NOTE: IT IS VERY IMPORTANT THAT YOU READ THIS SECTION TO PROVIDE YEARS OF
TROUBLE FREE USE. THIS UNIT REQUIRE CAREFUL HANDLING.
All warnings on the equipment and in the operating instructions should be adhered to and all
operating instructions should be followed.
Do not use this equipment near water. Care should be taken so that objects do not fall and liquids
are not spilled into the unit through any openings.
The power cord should be unplugged from the outiet when left unused for a long period of time.
DO NOT ATTEMPT TO SERIVCE THE EQUIPMENT. THIS EQUIPMENT SHOULD BE SERVICED BY
QUALIFIED SERVICE PERSONNEL ONLY. DO NOT REMOVE THE COVER FROM THIS EQUIP-
MENT AT ANY TIME. DO NOT MAKE ANY INTERNAL ADJUSTMENTS OR ADDITIONS TO THIS
EQUIPMENT AT ANY TIME. DO NOT TAMPER WITH INTERNAL ELECTRONIC COMPONENTS AT
ANY TIME. FAILURE TO FOLLOW THESE INSTRUCTIONS MAY VOID THE WARRANTY OF THIS
EQUIPMENT AS WELL AS CAUSING SHOCK HAZARD.
POWER REQUIREMENTS:
This unit accepts power from the 8V AC/1500mA adaptor supplied with the unit. This 9V RMS AC
voltage is internally processed by a voltage doubler, thus generating a bi-polar + & - 15V to maintain the
headroom and sound quality of professional, studio quality equipment. Using an external power source
such as this minimizes excessive noise and hum problems often associated with internal transformers,
giving the user optimal performance.
OPERATING TEMPERATURE:
Do not expose the unit to excessive heat. This unit is designed to operate between 32 F and 104
F (0 C and 40 ©). This unit may not function properly undsr extreme temperatures.
CLEANING INSTRUCTIONS:
Do not use cleaners such as Benzine to clean the exterior. Use a soft dry cloth to remove dust, dirt
or fingermarks. Internal cleaning should only be performed by authorized technicians.
FRONT PANEL DESCRIPTION
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The HUSH IICX™ has two identical channels. Each channel has the following controls, as well as
individual channel in/out switches and a stereo master switch.
(1)...POWER ON/OFF LED:
This LED indicates power On/Off.
(CHANNELS ONE AND TWO)
(2)... EXPANDER GAIN REDUCTION METER:
Indicates (in dB) amount of gain reduction taking place.
(3)...EXPANDER THRESHOLD NTROL:
Variable between -60 and 0dB.
This control sets the threshold point at which low level downward expansion begins once the input
signal drops below the level at which this control is set.
(4)...FILTER SENSITIVITY CONTROL:
Variable between -60 and OdB.
The Filter Sensitivity control allows the user to set the maximum sensitivity point (or minimum input
level) at which the filter of the HUSH™ will begin to operate.
(5)...FILTER BANDWIDTH METER:
Indicates (in KHz) the bandwidth of the filter.
(6)...RELEASE SWITCH:
This switch allows for a fast or slow expander release rate.
(7)...REFERENCE SWITCH:
This switch adjusts the sensitivity of the unit, optimizing it for either -10dB or +4dB operation.
(8)...CHANNEL IN/OUT SWITCH:
This switches the channel in for HUSH™ operation or out for bypass.
(9)...CHANNEL IN/OUT LED:
When lit, the LED indicates the channel is in.
(10)...STEREO MASTER SWITCH:
The Stereo/Master switch ties the expander and filter detection circuits of channel 1 and channel
2
2 together for stereo applications. This switch allows the user to select for either stereo or mono
applications. When the Stereo Master switch is in, channel 1's controls are master and channel 2's are
inoperable.
NOTE: To avoid mis-tracking when using the stereo master mode, make sure that both channels
reference switches are set in the same positions.
REAR PANEL DESCRIPTION
(CHANNELS ONE AND TWO)
(1)...INPUT JACKS:
These two standard unbalanced 1/4" mono jacks are used to provide input to the unit.
(2)...0UTPUT JACKS:
These two standard unbalanced 1/4™ mono jacks are used to provide the outputs of the unit.
NOTE: HUSH [ICX™ has a 470K input impedance which allows direct use with instruments, such as
guitars, with no loss of frequency response.
PRECAUTION: READ OUTPUT SPECIFICATIONS AND BASIC OPERATIONS FOR PROPER USE.
(3)...POWER JACK:
This unit accepts power from the SV AC/1500mA adaptor supplied with the unit.
CONNECTIONS AND APPLICATIONS
There are many possible applications for the HUSH IICX™. Make the appropriate connections as
shown below.
Guitar Applications
Guitar with effects and amplifiers. The HUSH™ helps to quiet effects.
MONO APPLICATION
FROM GUITAR CUTPUT
(or other testrument)
AUSH ox
STEREO APPLICATION
FROM GUITAR CUTPUT
{or other Instrument)
HUSH ex
Note: lt is possible to connect from effects, into the HHCX, while utilizing the effects loop of your amplifier.
This will help quiet the preamp section of the amplifier.
WARNING: Do not connect the “speaker out” of your amplifier into the HUSH lICX™ _ This may result in
severe damage to your IICX unit.
Recording Applications
MONO APPLICATION
FROM GUITAR OUTPUT
(or other Instrumerd)
№ TO MIXER
: St ir
ee UT 3 ЗНА: == he,
BE Нани ==
EERE a E wg
HUSH lICX
STEREO APPLICATION
FROM GUITAR OUTPUT
(or other Instrument)
MONO noisy 10 ff NOISY )9 S| noisy
EFFECT EFFECT |STEREO OUT
— TOMIKER
In the Studio
The HUSH™ has numerous applications for noise problems in the studio, from muiti-channel
mixdown and two channel mastering to reducing the noise in the recording of individual tracks. The
HUSH IICX™ provides excellent results when copying previously recorded tapes and can also be
used to quiet outboard signal processing gear in the studio such as digital delay lines, reverb units
and drum machines.
==
| OUT
A se
( NOISY EFFECT ) oe
OUT In
( NOISY EFFECT )
Two track recording
Patched in a channel of a mixing console for separate uses (vocals, guitar, etc.).
TO MIXER CHANNEL TO MIXER CHANNEL
INSERT POINT INSERT POINT
(TRACK 1) > (TRACK 2)
HUSH ИСХ
PA Applications
The HUSH™ can be used on the output feed to the mains to quiet both ambiance stage noise and
to reduce to inaudible levels the noise of mixing consoles and any cther signal processing devices used.
MONO APPLICATION
FROM OUTPUT OF TO MAIN
PA SYSTEM + "POWER AMP
HUSH исх
STEREO APPLICATION
—
TO MAIN
POWER AMPS
>
FROM OUTPUTS OF
PA SYSTEM
Live Monitor Applications
The lICX can be used to quiet monitor feed from the mixing console in a live application. This will
help quiet the stage mix and also greatly reduce the possibility of feedback from vocal microphones.
MONO APPLICATION
FROM MIXER
ouTeuTr № zu TO en
eyboard Application
The IICX can be used to quiet an entire keyboard mix before being fed to the power amplifier and
speakers.
J
о
=
FROM KEYBOARD
STEREO QUTPUT
Y
In the Home
The HUSHT may be used to reduce noise when making tapes (or copies) at home. By inserting
the HUSH 1ICX™ into the tape loop of a home stereo system, the HUSH™ can aslo be used to quiet
albums, compact discs, and FM broadcasts. The HUSH™ js also excellent for eliminating noise in the
home entertainment system present when processing audio signals from VCRs.
e PLAY
TAPE LOOP
— PLAY
TAPE LOOP
(o! home stereo)
OPERATION
The HUSH™ system incorporates the principles of dynamic filtering and low level expansion. The
dynamically controlled low pass filter is designed to open and close the bandwidth dependant upon the
amount of mid and high frequency information present in the audio signal. The filter bandwidth will open
to pass the high frequency information in the input signal while reducing the high frequency noise above
the highest input signal. For example, if the highest frequency present is 8KHz, the filter will open to pass
up to 8KHz while the noise from 8KHz to 20KHz would be reduced.
The Filter Sensitivity control on the front panel will determine the minimum input level at which the
filter will begin to operate.
When no mid or high frequency information is present, the filter will close down to a pre-set cut-off
point of 700Hz, allowing only frequencies below 700Hz to pass. The cut-off slope employs a 12dB per
octave filter.
The second half ofthe process incorporates downward expansion. Low level downward expansion
takes place when the input signal level drops below the threshold point, set via the Threshold control on
the front panel. This means that as the signal drops a certain level below the threshold point, the output
will be attenuated to an even greater degree, thus reducing noise. As the signal falls further below this
point, the ratio at which this occurs increases.
The basic operation of the HUSH [ICX™ has been divided into the functions of the separate controls
and switches. In order to obtain the best performance from your unit, read and understand how each
works.
EXPANDER METER:
The expander meter indicates the amount of expansion taking place. The meter reads the level of
gain reduction in decibels. For example, if both the 5dB and 10dB LEDs are lit, this indicates that at least
10dB of gain reduction is taking place.
| 30 20 10 > |
dB-GAIN REDUCTION — THRES
| EXPANDER
THRESHOLD CONTROL:
Ro pe
of fae fran
ee
pe
| EERE :
000 NZ
30 20-10 5 L
dB-GAIN REDUCTION THRES
EXPANDER
The threshold control sets the level at which broad band downward expansion begins. With the
control full counterclockwise, downward expansion begins at an input level of approximately -60dBv. As
the signal level drops below -60, the expansion ratio will increase, thereby providing more gain reduction
of the signal across the entire audio spectrum. The further the signal level decreases below this pre-set
threshold point, the more the ratio of expansion and resuliing gain reduction increasss.
Typlcal Expansion Ratio with 0dB Threshold
0 0
-10 -10
-20 TT] -20 .
-30 -30
INPUT _ap Ч -40 OUTPUT
fnd8) -50 .50 (in dE]
-60
-70
-80
-30
-100
With control full clockwise, the maximum gain reduction is provided. Downward expansion will
begin at approximately OdBv and increase as previously described as the signal level decreases.
8
SENSITIVITY CONTROL:
Sensitivity Control
©0098
___| 4 4 10 20
SENS BANDWIDTH-KHz
FILTER
To facilitate a better understanding of the sensitivity control, a more detailed description of the
dynamically controlled filter section of the HUSH™ will be given.
The dynamic filter circuit incorporates a frequency weighted detection circuit. This circuit senses
both the mid and high frequency content and the amplitude of the input signal and produces an output DC
signal which controls a voltage controlled low pass filter. If a large amount of high frequency information
IS present in the input signal, the filter will open to its full bandwidth (40KHz). Ifthe highest input frequency
is only 2KHz the filter will open to pass the 2KHz signal andits hamonic information while reducing any
noise present above this trequency. |
The sensitivity control is used to set the level at which the filter will open to pass the frequencies
contained within the input signal. Setting this control at a level too high for a particular application will
cause the filter to remain closed when a signal is present. When set too low, the filter will stay open when
a signal is not present, allowing all high frequency noise to pass.
FILTER BANDWIDTH
ANDAR
FILTER METER:
Filer Mater
0006!
| 1 4 10 20|
SENS BANDWIDTH-KHz
FILTER
The filter meter indicates the bandwidth that the dynamic filter is open to, as well as showing the
filter cut-off frequency when no input signal is present. The filteris always opento atleast 0.7KHz (400HZ).
Note: When an input signal's frequency component exceeds 700HZ, the filter meter will indicate an
increase in bandwidth.
9
RELEASE;
Releasa Dye? _
= SLOW | L]_-10
ны. +4
The release switch selects a fast or slow release time for the low level downward expander. Inthe
fast release mode, the release time is approximately 200ms for 20dB of expansion. The fast release is
recomended when the HUSH™ is used on individual tracks or instruments, or when used to quiet effects
which are used on a single audio source like individual instruments or vocals. The slow release provides
a release time of approximately 800ms for 20dB of expansion. The slow release mode is best used for
composite music or multiple audio signal applications.
REFERENCE SWITCH:
The reference switch adjusts the sensitivity of the unit. When using the HUSH ICX* with
professional audio equipment providing a nominal output level of +4dB, it is recommended using the +4
setting on the unit as the threshold adjustment will allow you to optimize noise reduction for this reference
level.
When using the unit with an instrument such as guitar or keyboards and their related equipment,
a setting of -10dB should be used unless the other equipment being used also incorporates a reference
level switch and is in a +4 position. Also, if a setting of -10 is used and the unit is overdriven, the +4 setting
should be used.
10
STEREO MASTER:
MASTER
When the stereo master switch is switched in, this ties the expander detection and filter detection
circuits of both channel 1 and channel 2 together. When using the stereo master, a high level, high
frequency signal present in one channel! will cause the expander and filter of both channels 1 and 2 to open
to the exact sarne point.
Note: To avoid mis-tracking when using the stereo master mode, make sure that both channels’
linefinst switches are set in the same positions, (i.e., both set to line or both set to inst.).
11
SPECIFICATIONS
INPUT
Input Impedance
Maximum Input Level
Input Jack
FREQUENCY RESPONSE
TOTAL HARMONIC DISTORTION
DYNAMIC RANGE
EFFECTIVE NOISE REDUCTION
FILTER
EXPANDER VCA
QUTPUT
Maximum +4 Ref Output Level
Maximum -10 Ref Output Level
Cutput Impedance
Cutput Jack
POWER REQUIREMENTS
DIMENSIONS
Note: OdBu = .775V RMS
470K ohms
+18dBu (+4 Ref) +5dBu (-10 Ref)
1/4" Mono
+/-0.5dB 30Hz to 20KHz
- Less than 0.03% at OdBu 1KHz
+4 Ref level
(threshold at minimum)
114dB Peak signal to A-weighted
noise floor
Greater than 60dB
Two pole Class A, 12dB per
octave slope
Quiescent cut-off 700Hz
Maximum Bandwidth 50KHz
Class A
+18dBu
+5dBu
Less than 100 ohms
1/4" Mono
9VAC RMS 750mA
19" X 6" X 1 3/4"
12
FORM #73 - 11/81
PART # 098-0040B
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