STEREO NOISE EXTERMINATOR FOR GUITAR PLAYERS
USER'S MANUAL
May be covered by one or more of the following: U.S. Patents #4538297, 4647876, 4696044, 4745309, 4881047, 4893099, 5124657, 5263091, 5268527,
5319713, 5333201, 5402498, 5493617 and 5638452. Other patents pending. Foreign patents pending.
Your
Super C
following Standards and Directives as set forth by the European Union:
This means that this product has been designed to meet stringent guidelines on how
much RF energy it can emit, and that it should be immune from other sources of interference when properly used. Improper use of this equipment could result in increased RF
emissions, which may or may not interfere with other electronic products.
To insure against this possibility, always use good shielded cables for all audio input and
output connections. Also, bundle audio cables separately from the AC power cables.
These steps will help insure compliance with the Directive(s).
For more information about other Rocktron products, please see your local dealer or one
of our importers closest to you (listed on the enclosed warranty sheet).
HUSH® noise reduction system has been tested and complies with the
Council Directive(s): 89/336/EEC Electromagnetic Compatibility
Standard(s): EN55013, EN50082-1
Copyright © 1997 Rocktron Corporation
All Rights Reserved.
Contents
Introduction ......................................................... 1
About the SSM2000.................................................1
Super C Front Panel............................................ 3
Super C Rear Panel............................................. 4
System Connections........................................... 5
Mono Applications ...................................................5
Stereo Applications..................................................6
Operation ............................................................. 7
HUSH® Section.......................................................7
Gate Section............................................................9
Specifications.................................................... 10
Introduction
Congratulations on your purchase of the Rocktron HUSH® Super C™!
Designed for guitar applications, the Super C utilizes the latest in HUSH noise
reduction technology (including the SSM2000 HUSH IC, available from Analog
Devices) combined with the latest V.I.R. (Variable Integrated Release) circuitry
configured as a noise gate. This combination provides extremely effective noise
reduction while playing and complete silence when not.
Although the Super C is a stereo noise reduction system, a single HUSH
Threshold and Gate Threshold are used to control both channels.
This manual will introduce you to the various features and functions of the
Super C. Please keep it for future reference.
About the SSM2000...
The SSM2000 is an advanced audio noise reduction system based on
patented HUSH® technology. The SSM2000 is commercially available from
Analog Devices, produced under the license of the HUSH patents. HUSH
combines a dynamic filter and downward expander to provide a high level
effectiveness without the sonic artifacts normally associated with noise
reduction systems. In addition, an Adaptive Threshold circuit detects
nominal signal levels and dynamically adjusts both thresholds, thereby
providing optimal results regardless of program source. Since it is a singleended system, HUSH can be used on virtually any audio source, including
audio and video tapes, radio and television broadcasts, or any other source
with objectionable noise. The SSM2000 can also be used with Dolby
encoded sources with excellent results.
FEATURES:
• Up to 25dB of noise reduction from
virtually any audio source without sonic
artifacts
• External port available for additional
attenuation— providing in excess of 85dB
of noise reduction
• "Single-ended" operation eliminates need
for encode-decode process
• Adaptive threshold dynamically adjusts to
changing nominal signal levels
®
• Effectively decodes Dolby
sources
encoded
• Direct VCA control port access for additional
level control functionality
• Logic-controllable bypass and muting
• Flexible on-chip voltage reference
• 100dB dynamic range (noise reduction OFF)
• 0.02% typical THD+N (@ 1kHz, noise
reduction OFF)
• +7V to +20V operation
• No royalty requirements
®
®
1
OPERATING PRECAUTIONS
NOTE: IT IS VERY IMPORTANT THAT YOU READ THIS SECTION
TO PROVIDE YEARS OF TROUBLE FREE USE. THIS UNIT
REQUIRES CAREFUL HANDLING.
All warnings on this 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 outlet when left unused
for a long period of time.
DO NOT ATTEMPT TO SERVICE THIS EQUIPMENT. THIS
EQUIPMENT SHOULD BE SERVICED BY QUALIFIED PERSONNEL
ONLY. 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 9VAC/2A adaptor supplied with the
unit. This 9 volt RMS AC voltage is internally processed by a voltage
doubler which generates a bipolar ±15 volts 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, providing
optimal performance for the user.
OPERATING TEMPERATURE
Do not expose this unit to excessive heat. This unit is designed to
operate between 32° F and 104° F (0° C and 40° C). This unit may
not function properly under extreme temperatures.
2
Super C Front Panel
POWER
LED
When lit, this LED indicates that the Super C is powered and ready for operation.
HUSH THRESHOLD
This control sets the point at which the downward expander and dynamic filter begin
to operate.
GATE THRESHOLD
This control is used to determine the level at which the gate will begin to operate.
As the input signal drops below this level, the gate will activate and downward
expansion will begin.
When lit, the Gate Release LED indicates that the input signal has dropped below
the level set by the Gate Threshold control, thus activating the gate and providing
additional downward expansion.
IN/OUT
REF switch
switch and LED
This switch allows for the Super C to be bypassed when noise reduction is not
required.
When lit, the LED indicates that the Super C is currently active in the signal path.
This switch determines the sensitivity of the Super C. When using the Super C with
professional audio equipment providing a nominal output level +4dB, it is
recommended that the "+4dB" setting on the unit as the Threshold adjustment will
allow you to optimize noise reduction for this reference level.
control
control and
GATE RELEASE
LED
If the "-10" setting is used and the unit is overdriven, the "+4" setting should be used.
3
Super C Rear Panel
CH. A (MONO) / CH. B IN
These ¼" mono jacks provide inputs to the left and right channels of the Super C.
When using only one input, the "CH. A (MONO)" jack must be used.
jacks
CH. A / CH. B OUT
These ¼" mono jacks provide outputs from the "CH. A" and "CH. B" channels of the
Super C.
Note: When "CH. A" is used as a single signal source, the signal will be
POWER
This 2.5mm pin jack accepts power from the 9VAC adapter supplied with the unit.
jack
jacks
present in both the "CH. A" and "CH. B" outputs.
4
System Connections
Mono Applications
5
Stereo Applications
6
Operation
When used properly, the HUSH® Super C should be completely
transparent (i.e., it should not effect the guitar signal—only the noise). To
maximize the performance of the Super C, it is necessary to understand its
front panel controls and how they work together. By understanding how
these controls work, it will be easier to correctly set up the Super C to suit
any application.
The Super C front panel provides two controls which each manipulate
both channels simultaneously. The
of noise reduction required for a given input signal, while the
control provides additional downward expansion when increased. (The
Threshold
strictly a downward expander.)
control may also be used by itself, allowing the unit to be used as
HUSH Threshold
control sets the amount
Gate Threshold
Gate
HUSH® Section
Rocktron's patented HUSH® noise reduction is a single-ended system
that combines the principles of
expansion
to open and close the bandwidth of the output signal depending upon the
amount of mid and high band information present in the input signal. The
filter bandwidth will only open far enough to pass the highest frequency
information in the input signal, thus reducing the noise above it.
8kHz, the filter will open to pass up to 8kHz while the noise from 8kHz to
20kHz would be reduced. If a signal with frequency components up to 20kHz
appears at the input, the dynamic filter will open to its full extreme (40kHz).
.
Dynamic filtering is achieved by dynamically-controlling a low pass filter
For example, if the highest frequency present in the input signal is
dynamic filtering
Dynamic Filtering
and low-level
downward
7
This means that if a signal is present at the input which consists of
primarily bass components, the dynamic filter will reduce mid or high band
noise. If no mid or high band information is present, the filter will close
down to a pre-set cut-off point of 1kHz (allowing only frequencies of 1kHz
and below to pass). However, if the input signal has high frequency
components present, the dynamic filter will open fully to pass the signal
and eliminate the possibility of a loss of high end frequency response.
Downward Expansion
The second half of the HUSH® process incorporates downward
expansion. The low level expander of the HUSH® system operates like an
electronic volume control. The HUSH® system utilizes a voltage-controlled
amplifier (VCA) circuit which can control the gain between the input and
the output from unity to 30, 40 or even 50dB of gain reduction. When the
input signal is above the user preset threshold point, the VCA circuit
remains at unity gain. (This means that the output signal level is equal to
the input signal level.) As the input signal level drops below the user
preset threshold point, downward expansion begins. It is at this point that
the expander acts like an electronic volume control and gradually begins
to decrease the output signal level relative to the input signal level.
As the input signal drops further below the threshold point, downward
expansion increases. A drop in the input level by 20dB would cause the
output level to drop approximately 40dB (i.e., 20dB of gain reduction). In
the absence of any input signal, the expander will reduce the gain so that
the noise floor becomes inaudible.
8
The front panel
level at which the HUSH filter and downward expander will begin to operate.
Setting this control too high will result in a loss of sustain, as notes will tend
to die out much faster than they should. Conversely, when set too low, the
expander will close too late (if at all) and the noise floor will remain audible.
HUSH Threshold
control determines the minimum input
Gate Section
The other half of the Super C consists of a noise gate. A noise gate
completely shuts off the output signal when the input signal level drops
below a prescribed threshold level (volume). On the Super C, this threshold
is determined by the Gate Threshold control on the front panel. This control
should be set so that it doesn't cut notes off (i.e., set too high), yet doesn't
activate long after a note ends (allowing the noise floor to remain audible).
This circuit is combined with the Variable Integrated Release (V.I.R.)
circuit to provide an internal variable release to the downward expander.
With the V.I.R. circuit, if the guitar signal decays slowly, the downward
expander will engage slowly. If the guitar signal stops quickly, the downward
expand will engage quickly. The LED indicates when downward expansion is
active.
9
Specifications
Maximum Input Level
Input Impedance
Output Impedance
Effective Noise Reduction
Frequency Response
Dynamic Range
Noise Floor
THD + Noise
Current Consumption
Dimensions
Note: 0dBv = 0.775V RMS
CE Approved
+15dB (+4 Ref.)
+5dB (-10dB Ref.)
470KΩ
less than 100Ω
72dB
±.5dB, 10Hz - 27kHz
105dB
-100dBu
.041% @ 0dBu, 1kHz (typ)
385mA
19" x 6" x 1¾"
Rocktron Corporation
2870 Technology Drive
Rochester Hills, MI 48309
USA
Phone:
Fax:
World Wide Web:
E-mail:
10
(248) 853-3055
(248) 853-5937
http://www.rocktron.com
rocktron@eaglequest.com
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