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TUBE EQ
PROFESSIONAL TUBE PARAMETRIC EQUALIZER
USER’S GUIDE
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Introduction 2
Features 2
Registration 3
Overview 3
EQ Tips 4
Unpacking 7
AC Power Hookup 7
Audio Connections 7
Installation 7
Safety Precautions 7
Powering Up 8
Front Panel Controls and Indicators 8
Bypass Switch 8
Gain Control 9
Clip Indicator 9
Output Level Control 9
Instruments and the Audio Spectrum 10
Low Frequency Control 10
Low Shift Switch 11
Lo-Mid Frequency Control 11
Low-Mid Shift x10 Switch 11
Hi-Mid Frequency Control 12
Hi-Mid Shift x10 Switch 12
High Frequency Control 12
High Shift Switch 13
Rear Panel Connections 13
Power Switch 13
Input 14
Output 14
Tube Replacement 14
Applications 15
Specifications 16
On-line Information 16
Warranty Information 17
Service Information 18
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128-5004-101
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Thank you for purchasing Applied Research and Technology’s
Tube EQ. The Tube EQ may be used anywhere you need equalization or frequency adjustments. Offering a superb level of
sound quality, the Tube EQ will enhance the sonic textures of
your audio system for years to come.
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The Tube EQ is a unique product. While every EQ gives you the
ability to alter the frequency characteristics of a signal, very few
sound
really
good when doing so. Developed in partnership with
studio and live sound engineers, the Tube EQ possesses flexibility
and “sound” that is not available from any other product on the
market - at any price! The Tube EQ was designed and constructed with the best components, assuring a lifetime of quiet, reliable performance. The Tube EQ offers:
- The award-winning A R T “SOUND”!
- Tube-based four-band equalization
- Selectable Low shelving filter - 40Hz or 120Hz
- Selectable High shelving filter - 6KHz or 18KHz
- Sweepable Lo and Hi mid-frequency bands
- Mid-frequency bands overlap from 200Hz to 2KHz
- Mid-frequency bands sweepable from 20Hz to 20KHz
- Hand-selected 12AX7a tube
- XLR balanced inputs and outputs
- 1/4” TS unbalanced inputs and outputs
- Custom extruded aluminum chassis
- Independent input and output level controls
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- Detented rotary controls
- >90dB dynamic range
- Internal power supply
- One year warranty
- Designed and manufactured in the USA
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If you haven’t done so already, please take the time to fill out the
User Registration Card for your purchase. Having you in our
database allows us to keep you informed of updates, application
notes, and new product introductions. It only takes a moment,
and it will ensure that you are constantly up to date with your
purchase.
Fill in the following for your future reference:
Date of purchase: ___________________
Purchased From: ____________________
Serial Number: 128-________
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Great recordings and great mixes are made from great sounds.
With the exception of some classical and environmental recordings, equalization plays a large role in creating, tweaking and
capturing great sounds in contemporary music. A good equalizer
will make good sounds sound better, and (more importantly) bad
sounds sound better.
Since we don’t live in a perfect world where all instruments and
sounds are “record-ready”, A R T created the Tube EQ to make
our recordings a little easier and (hopefully) a little better.
The Tube EQ was designed to help “fix” the instruments that give
us the most headaches when we’re recording: kick, snare, bass,
toms, guitar amps, voice, etc. The two sweepable parametric
bands and selectable shelving bands have been optimized for
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musical instruments. The two sweepable bands overlap themselves and the high and low shelving bands, providing you with
the ultimate in flexibility. The Tube EQ gives you all the control
you need to effectively alter and dial in great sounds from even
the poorest of sources.
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The shortest signal path is the best way to get a signal to tape.
In most cases, the shortest path is: mic to preamp to compressor
to EQ to tape deck. The signal doesn’t even go through the
mixer! This isn’t a new concept, but it has become more relevant
with the availability of affordable mixing consoles. As their name
implies, most affordable mixers excel in signal routing and mixing capabilities. However, they are not necessarily your best
option for recording tracks. While their onboard EQ is nearly
always adequate for tweaking a good recorded track during
mixing, the simple truth is that the Tube EQ is a better sounding
and more flexible equalizer. Mixer manufacturers need to make
trade-offs to keep prices down while keeping performance up.
Imagine the price of your mixer if each channels’ EQ cost over
$200 (and we’re not
talking about those of you who have one of
those $250,000+ consoles!)
The use of external processing (equalizers, preamps and compressors) has sonic and practical benefits when you consider that
most recording is done one or two channels at a time. For those
of us on a budget, it just doesn’t make sense to spend a ton of
money on a “cadillac” console when a budget mixer and a few
pieces of external gear is more cost effective. Even those engineers who regularly work on “big” consoles use external EQs
and preamps!
The goal of any recording is to get the sounds right before you
commit them to tape. The Tube EQ exists to help you get it right
so you don’t have to “fix it in the mix”.
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Every EQ has its place. As a general rule of thumb, parametric
EQs are used for individual instruments (or tracks) and graphic
EQs are used for mixed material and for playback systems.
Parametric EQs give you more control over a signal -- they can
provide subtle or drastic results because they can be tuned to
specific frequencies. Parametric EQs allow you to boost or cut
narrow frequency bands to make individual instruments “sit” better with other instruments when combined in a mix. This is usually accomplished with one or two bands. Graphic EQs are used
more for the shaping of material. They are nearly always used in
PA systems because they can adjust the speaker system to fit the
needs of a room while still sounding natural. Their application is
“broader” than that of a parametric.
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There are two schools of thought on EQ: 1) Use as much as you
need to make things sound good. 2) Don’t use any EQ. Most
people follow the suggestion of “if it sounds good, it is good.”
You need to use your ears and judge for yourself as their are no
steadfast rules for EQ’ing. Here are a few pointers to guide you.
Always tweak the instrument you are EQ’ing while listening to it
in the mix. EQ’ing an instrument when it is soloed doesn’t give
you a good representation of how it will sound when mixed with
other instruments. You’d be surprised at how
bad
a killer guitar
track can sound when it is isolated from the rest of the mix.
Remember, what makes it killer is how it sounds in relation to
the other instruments! Keep the big picture in mind.
Most people think of EQ as boosting only (“we’ll just add a little
EQ...”). Many times a “bad” sounding instrument can be fixed
by simply isolating the bad frequency and pulling it out. After
you determine approximately where the “problem area” is in the
instrument (highs, lows, mids), isolate the track and boost one of
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