Behringer Tube Ultra-Q T1951 User manual

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EUser´s Manual
Bedienungsanleitung
Version 1.0 December 1998
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TUBEULTRA-Q® T1951
www.behringer.de

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acc. to the Directives
89/336/EWG and 73/23/EWG
We, BEHRINGER INTERNATIONAL GmbH
Hanns-Martin-Schleyer-Straße 36-38
D - 47877 Willich
Name and address of the manufacturer or the introducer of the product on the market who is established in the EC
herewith take the sole responsibility to confirm that the product:
TUBEULTRA-Q T1951
Type designation and article-No (if applicable)
to which this declaration refers, is in accordance with the following standards or stan-
dardized documents:
xEN 60065 xEN 61000-3-2
xEN 55020 xEN 61000-3-3
xEN 55013
The following operation conditions and installation arrangements have to be presumed:
acc. to Operating Manual
B. Nier, President Willich, 01.12.1998
Name, address, date and legally binding signature of the person responsible
EC-Declaration of Conformity
INTERNATIONAL GmbH

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This symbol, wherever it appears, alerts
you to the presence of uninsulated
dangerous voltage inside the enclosure
- voltage that may be sufficient to con-
stitute a risk of shock.
This symbol, wherever it appears, alerts
you to important operating and mainte-
nance instructions in the accompanying
literature. Read the manual.
SAFETY INSTRUCTIONS
CAUTION: To reduce the risk of electrical shock, do not remove
the cover (or back). No user serviceable parts inside;
refer servicing to qualified personnel.
WARNING: To reduce the risk of fire or electrical shock, do not
expose this appliance to rain or moisture.
DETAILED SAFETY INSTRUCTIONS:
All the safety and operation instructions should be read before the appliance is operated.
Retain Instructions:
The safety and operating instructions should be retained for future reference.
Heed Warnings:
All warnings on the appliance and in the operating instructions should be adhered to.
Follow instructions:
All operation and user instructions should be followed.
Water and Moisture:
The appliance should not be used near water (e.g. near a bathtub, washbowl, kitchen sink, laundry tub, in a wet
basement, or near a swimming pool etc.).
Ventilation:
The appliance should be situated so that its location or position does not interfere with its proper ventilation.
For example, the appliance should not be situated on a bed, sofa rug, or similar surface that may block the
ventilation openings, or placed in a built
in installation, such as a bookcase or cabinet that may impede the flow of air through the ventilation openings.
Heat:
The appliance should be situated away from heat sources such as radiators, heat registers, stoves, or other
appliance (including amplifiers) that produce heat.
Power Source:
The appliance should be connected to a power supply only of the type described in the operating instructions
or as marked on the appliance.
Grounding or Polarization:
Precautions should be taken so that the grounding or polarization means of an appliance is not defeated.
Power-Cord Protection:
Power supply cords should be routed so that they are not likely to be walked on or pinched by items placed
upon or against them, paying particular attention to cords and plugs, convenience receptacles and the point
where they exit from the appliance.
Cleaning:
The appliance should be cleaned only as recommended by the manufacturer.
Non-use Periods:
The power cord of the appliance should be unplugged from the outlet when left unused for a long period of time.
Object and Liquid Entry:
Care should be taken so that objects do not fall and liquids are not spilled into the enclosure through openings.
Damage Requiring Service:
The appliance should be serviced by qualified service personnel when:
- The power supply cord or the plug has been damaged; or
- Objects have fallen, or liquid has been spilled into the appliance; or
- The appliance has been exposed to rain; or
- The appliance does not appear to operate normally or exhibits a marked change in performance; or
- The appliance has been dropped, or the enclosure damaged.
Servicing:
The user should not attempt to service the appliance beyond that is described in the Operating Instructions. All
other servicing should be referred to qualified service personnel.

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T1951
TUBEULTRA-Q
Ultra-musical 4-band Tube Parametric Equalizer delivers outstanding equalization both in live applications and in the studio
sFor gentle contouring and audio sweetening in audio post-production and recording studios
sFor room equalization and extreme corrective surgery e.g. notching out unwanted frequencies
sOur new ULTRA-TUBE circuitry warms up your music without unwanted noise
sA special Warmth control lets you add the amount of tube sound you want
sSelected 12AX7 tubes for outstanding, ultra-musical tube sound
sParallel filter architecture ensures minimal phase shift and extremely transparent audio performance
sPrecision State-Variable filters with Constant-Q principle ensure absolutely stable filter characteristics
sEach band is switchable in/out and is fully adjustable from extremely narrow notch filter (0.03 octave) to
broadband equalization (2 octaves)
sA wide overlap between frequency bands allows for extreme cut or boost
sAdditional sweepable High and Low Cut filters remove unwanted frequencies e.g. floor rumble and tape hiss
sServo-balanced inputs and outputs
sGold-plated XLR and 1/4 TRS connectors
sRelay-controlled Hard-Bypass with an auto-bypass function during power failure (failsafe relay)
sCut-in delay to avoid switch-on thumps
sUltra-low noise 4580 audio operational amplifiers offer outstanding sound performance
sHigh-quality detented potentiometers and illuminated switches
sHuge back-lit analog VU meters with stylish Retro design
sBEHRINGERs high-performance OT-1 output transformer retrofittable
sHigh-quality components and exceptionally rugged construction ensures long life
sManufactured under the stringent ISO9000 management system

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FOREWORD
Dear Customer,
We thank you for expressing your confidence in Behringer products by purchasing the Behringer TUBEULTRA-Q.
It is one of my most pleasant tasks to write this preface, as our engineering team has made it possible to
enhance the traditional tube circuitry design (particularly for our Vintager® series of products), and adapt it to
meet the high sound quality and dynamics requirements of modern, pro-level audio technology. The fact that
we are still fascinated by antique tube radios and amps as well as the fine and warm tonal character that we
usually associate with them, are the reasons why vacuum tubes have kept their ground even in state-of-the-art
circuit topologies used especially in professional audio technology or high-end devices. We are particularly
proud that we have found an extremely effective symbiosis between solid-state and tube technologies making
them affordable to anybody interested in audio technology. As always, our top-priority concern when develop-
ing this device was the demanding end user, in other words: you. It was our major goal to meet your demands.
Sure, it meant a lot of hard work to develop such a product, but the fun has made it all worthwhile. The shine in
the eyes of the many interested musicians at the Music Fair 1997, when they saw our Vintager models for the
first time, was a lasting incentive driving our development efforts.
It is our philosophy to share our joy with you, because you are the most important member of the BEHRINGER
family. With your highly competent suggestions for new products youve greatly contributed to shaping our
company and making it successful. In return, we guarantee you uncompromising quality (manufactured under
ISO9000 certified management system) as well as excellent technical and audio properties at an extremely
favorable price. All of this will enable you to fully unfold your creativity without being hampered by budget
constraints.
We are often asked how we can make it to produce such high-grade devices at such unbelievably low prices.
The answer is quite simple: its you, our customers! Many satisfied customers means large sales volumes
enabling us to get better conditions of purchase for components, etc. Isnt it only fair to pass this benefit back
to you? Because we know that your success is our success, too!
I would like to thank all people whose help on Project TUBEULTRA-Q has made it all possible. Everybody
has made very personal contributions, starting from the designers of the unit via the many staff members in our
company to you, the user of BEHRINGER products.
My friends, its been worth the effort!
Thank you very much,
Uli Behringer

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TABLE OF CONTENTS
1. INTRODUCTION..................................................................................................................... 7
1.1 The concept .................................................................................................................................... 7
1.2 Before you begin ............................................................................................................................. 7
1.3 Control elements ............................................................................................................................. 8
2. OPERATION .......................................................................................................................... 10
2.1 Introduction ................................................................................................................................... 10
2.2 The TUBEULTRA-Q in the signal path ......................................................................................... 10
2.3 Filter settings ................................................................................................................................ 10
2.4 Setting of the Tube Stage .............................................................................................................. 12
3. APPLICATIONS ..................................................................................................................... 12
3.1 Filtering out unwanted frequencies ................................................................................................ 12
3.2 Shelving filters and Roll Off.......................................................................................................... 13
3.3 Equalizers as creative audio tools ................................................................................................. 13
3.4 The TUBEULTRA-Q as tube interface ........................................................................................... 15
3.5 EQ-ing a P.A. system ................................................................................................................... 15
4. TECHNICAL BACKGROUND .............................................................................................. 17
4.1 Function ........................................................................................................................................ 17
4.2 The Constant-Q principle............................................................................................................. 17
4.3 The concept of parallel filters ......................................................................................................... 17
4.4 On phase shift and time delay ....................................................................................................... 18
4.5 Tubes used in the TUBEULTRA-Q ................................................................................................ 18
4.5.1 Tube history ........................................................................................................................ 18
4.5.2 Design and functional principle of tubes .............................................................................. 19
4.5.3 Properties of tubes .............................................................................................................. 20
4.5.4 The best of both worlds ....................................................................................................... 20
4.5.5 UTC circuit .......................................................................................................................... 21
4.5.6 Studio applications .............................................................................................................. 21
5. INSTALLATION ..................................................................................................................... 22
5.1 Rack mounting .............................................................................................................................. 22
5.2 Mains voltage ................................................................................................................................22
5.3 Audio connections ........................................................................................................................ 22
5.4 Transformer-balanced outputs (optional) ........................................................................................ 24
6. SPECIFICATIONS ................................................................................................................. 25
7. WARRANTY ........................................................................................................................... 26

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1. INTRODUCTION
With the BEHRINGER TUBEULTRA-Q T1951 you purchased an innovative device. Parametric equalizers
represent the most advanced form of equalization systems. With the TUBEULTRA-Q you have purchased an
extremely musical and flexible device. Our ULTRA-Q range of devices has been a hit ever since we introduced
our first model some 5 years ago. This high-end parametric equalizer is based on many years of experience
and findings in equalizer technology and is used throughout the world in renowned studios, sound reinforce-
ment systems as well as in broadcast and television studios. Improving the legendary ULTRA-Q even further
was a real challenge, and we are proud of our success. The BEHRINGER TUBEULTRA-Q meets highest
requirements in terms of operation, sound, specifications and workmanship.
Even at the conception of the TUBEULTRA-Q it was clear that we had to combine the outstanding technical
specifications of our ULTRA-Q with a warm tube sound. We are therefore proud to be able to present TUBE
ULTRA-Q, a device featuring our newly developed UTC vacuum tube circuit combined with a no-compromise
approach. The newly developed UTC circuit provides subtle sound enhancement rather than showy effects
processing. In particular, digital workstations can be considerably enhanced in their sound character. You are
free to use the TUBEULTRA-Q before the recording sessions or later when you mix down the music you
recorded. You can also use it to brighten up entire MIDI productions or even movie sound recordings and thus
give them their finishing touch.
The philosophy behind BEHRINGER products guarantees a no-compromise circuit design and employs the
best choice of components. The op-amps, type 4580, used in the TUBEULTRA-Q are chosen for their superior
signal-to-noise ratio, low distortion and linear performance. Additionally, the TUBEULTRA-Q uses high qual-
ity resistors and capacitors with very tight tolerances, high-grade switches as well other selected components.
The TUBE ULTRA-Q is manufactured under the ISO900 management system.
With the exception of two 12AX7/ECC83 tubes, the TUBEULTRA-Q T1951 is based on SMD technology
(Surface Mounted Devices). These subminiature components known from aerospace applications ensure both
extreme packing density and greater reliability.
+Please keep the manual after reading, in order to use it for future reference.
1.1 The concept
The heart of the TUBEULTRA-Q is a extremely low-noise and transparent sounding state-variable filter. In
combination with the Constant-Q principle, the 4589 op-amp and the newly developed ULTRA-TUBEÒtechnol-
ogy, the TUBEULTRA-Q achieves extremely low noise and distortion figures together with an incredible warm
sound. With four fully parametric bands, it offers you truly professional signal processing.
In the TUBE ULTRA-Q two selected 12AX7 / ECC83 vacuum tubes are used. These triodes are capable of
handling a large dynamic range with little microphony. In addition to that their relative ruggedness and above
average life span and you can see why its one of the most popular and reliable pre-amp tubes on the market.
These features also ensure you their availability for many years to come.
Failsafe relays have been incorporated into the design of the BEHRINGER TUBE ULTRA-Q, which automati-
cally and silently bypass the unit in the event of power supply disconnection or failure. These relays are also
active at switch-on to isolate the TUBE ULTRA-Q until the power rails have settled, thus preventing the possi-
bility of a potentially damaging switch-on thump.
1.2 Before you begin
Your BEHRINGER TUBE ULTRA-Q was carefully packed in the factory and the packaging was designed to
protect the unit from rough handling. Nevertheless, we recommend that you carefully examine the packaging
and its contents for any signs of physical damage, which may have occurred in transit.
+If the unit is damaged, please do not return it to us, but notify your dealer and the shipping
company immediately, otherwise claims for damage or replacement may not be granted.
Shipping claims must be made by the consignee.
The BEHRINGER TUBE ULTRA-Q fits into two standard 19" rack units of space. Please allow at least an
additional 4" / 10 cm depth for the connectors on the back panel.
1. INTRODUCTION

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Be sure that there is enough space around the unit for cooling and please do not place the TUBE ULTRA-Q on
high temperature devices such as power amplifiers etc. to avoid overheating.
+Before you connect your TUBEULTRA-Q to the mains, please make sure that your local volt-
age matches the voltage required by the unit!
The mains connection of the TUBEULTRA-Q is made by using a mains cable and a standard IEC receptacle.
It meets all of the international safety certification requirements. Please make sure that all units have a proper
ground connection.
+Please ensure that only qualified persons install and operate the TUBEULTRA-Q. During in-
stallation and operation the user must have sufficient electrical contact to earth. Electrostatic
charges might affect the operation of the TUBEULTRA-Q !
Additional information you will find in Chapter 5 INSTALLATION.
As a standard the audio inputs and outputs on the TUBEULTRA-Q are fully balanced. If possible, connect the
unit to other devices in a balanced configuration to allow for maximum interference immunity. The automatic
servo function detects unbalanced connections and compensates the level difference automatically (6dB
correction).
1.3 Control elements
The BEHRINGER TUBEULTRA-Q has four parametric filters organized in 4 different frequency bands. A
backlit VU meter shows the input or output level. Each channels comes with a Warmth control, and a tube
window.
Fig. 1.1: Control elements on the front panel
1The INPUT control determines the input level applied to the device and can be set within a range from
-15 to +15dB.
2When the PEAK LED above the INPUT control lights up, it means that a level of at least 18dBu is
present after the input stage. Adjust the INPUT control so that the PEAK LED lights up only with signal
peaks, make sure that it never lights up all the time. When the PEAK LED is on there is still some 5dB
of headroom left.
+Please note that extreme boost settings in combination with a high input level can overload
the unit. In such a case, the input level must be reduced with the INPUT control.
3The IN/OUT switch is used to enable/disable the entire equalizer section in the audio path. The switch
uses a relay-controlled hard-bypass function, i.e. as long as it is not active or if the unit is switched off,
the inputs are directly connected to the outputs. The AUDIO IN/OUT switch allows for A/B comparisons
between the processed and unprocessed signals.
1. INTRODUCTION

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4The FREQUENCY control selects the filters center frequency, which can be freely chosen from within
the frequency range of the associated band.
5The LEVEL control determines the amount of level boost/cut. The setting range is from -15 to +15dB.
6The BANDWIDTH control determines the slope or quality of the filter. Settings from 0.03 (Q=43) to 2
octaves (Q=0,67) are possible. A small bandwidth (high Q) means that the only a small portion of the
total frequency range will be affected while a wide bandwidth (low Q) means that a large part will be
affected.
7With the SHELF/PEAK switch the two outer bands can be switched from parametric (peaking re-
sponse) EQ to low and high pass (shelving EQ) filters respectively. Use this feature to eliminate rumble,
plop and breathing noises from the bottom end and noise or hiss from the top end. When switched to
PEAK mode the filters operate identical to the other filters.
8The individual IN/OUT switches allow for enabling/disabling specific bands in the audio path. Use this
switch to check the influence of the separate filters and to switch unused filters of for maximum signal
integrity.
Fig. 1.2: Control elements on the front panel
9The WARMTH control determines the amount of harmonics the UTC circuit adds to the signal. This is
the amount of tube sound (WARMTH) that is added.
The WARMTH meter displays the amount of added harmonics. This control the amount of harmonics, or
tube sound (WARMTH), the UTC circuit adds to the signal is set. This is the amount of tube sound that
is added.
11 Use the POWER switch to turn the TUBE ULTRA-Q on or off. When switched of the TUBE ULTRA-Q
automatically switches to a hard-bypass mode, the signal is then led directly to the outputs.
13 15
1412
Fig. 1.3: Rear panel elements of the TUBEULTRA-Q
1. INTRODUCTION

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12 SERIAL NUMBER. Please take the time to have the warranty card filled out completely by your special-
ized dealer and return it within 14 days after the date of purchase, so as to be entitled to benefit from our
extended warranty.
13 MAINS CONNECTION / FUSE HOLDER - VOLTAGE SELECTOR. Use the enclosed power cord to
connect the unit to the mains. Please also note the instructions given in the INSTALLATION Chapter.
Please make sure that your local voltage matches the voltage indicated on the unit, before you attempt
to connect and operate the TUBEULTRA-Q. Blown fuses may only be replaced by fuses of the same
type and rating.
14 AUDIO IN. These are the audio inputs of your TUBEULTRA-Q, available both as balanced 6.3 mm TRS
jack and XLR connectors.
15 AUDIO OUT. These are the audio outputs of your TUBEULTRA-Q. Matching phone jack and XLR
connectors are wired in parallel. The automatic servo function recognizes balanced or unbalanced con-
nection and automatically compensates for the difference in level (correction 6dB). The BEHRINGER
OT-1 output transformer is optionally retrofittable.
2. OPERATION
2.1 Introduction
The BEHRINGER TUBE ULTRA-Q gives you a combination of all technical properties both of parametric
equalizers and of narrow-band notch filters. With its excellent audio quality and outstanding specifications it is
simply better than any conventional equalizer. The ULTRA-Q can be used to make up for frequency response
deficiencies and to creatively process any audio material, thus giving you undreamed-of equalization flexibility.
It is a highly efficient and all-purpose tool both in creative audio processing in broadcast and television studios,
in video post-production and on stage. Each of its four bands can be freely adjusted in quality: from extremely
narrow to broad-band. The TUBEULTRA-Q is superior to graphic equalizers in all respects.
The BEHRINGER TUBE ULTRA-Q uses our newly developed ULTRA-TUBE technology, a development result-
ing from two years of intensive research work by our engineering team. The ULTRA-TUBE technology over-
comes the problems related to tube circuitry (see Chapter 4) and generates upper harmonics even at low levels
to give your recordings more warmth and power.
2.2 The TUBEULTRA-Q in the signal path
The best point to insert the TUBEULTRA-Q in the signal path depends on the task on hand: basically, it can
be inserted in the line insert points of the mixing console, Subgroup inserts, Subgroup outputs, effect paths or
between signal processor(s) and mixing console / power amp, etc.
Another possibility is to insert the TUBEULTRA-Q in the Subgroups of the mixing console (if available).
Depending on the wiring of the inserts on the console, you either need a special 6.3mm stereo phone-jack
insert cable that is routed to two mono jacks (send & return), or two separate cables for the send and return
path. Connect the insert sends of the Subgroups to the inputs on the TUBEULTRA-Q, and the insert returns
to the outputs.
You can also connect the TUBEULTRA-Q to the insert of two independent channels of your mixer. This way
the TUBEULTRA-Q acts as an high-quality an versatile channel EQ. You can even connect the two channels
of the TUBEULTRA-Q in series to make one equalizer with 8 bands! Connect the output of channel one with
the input of channel two. Set the output of channel one as well as the INPUT control of channel two at 0dB.
2.3 Filter settings
You may find that getting to know a dual channel processor like the TUBEULTRA-Q is easier when you
concentrate on one channel first. If you have a mixer, connect the TUBEULTRA-Q to the insert of one channel
only.
Always start off by setting all controls to neutral. All gain controls at 0dB and bandwidth wide. This prevents
2. OPERATION