realbass SINGLE User manual

Manual
Single
Duo

07.09.2017
2
Preface by the developer
The design and engineering of the originate from Germany.
All components, and the equipment and installation, are manufactured
exclusively by domestic partners to the highest quality standards. This
allows us to implement ideas consistently, sustainably, quickly and
efficiently.
All equipment in the range are conceived to be purely
analogue devices and are governed by this philosophy. Economic
factors are of less significance than “undistorted tone” in design and
production.
Great attention is paid to the weight in the development of the equipment. Its ”Sound” has top
priority in this case.
Our own experience gained over many years of playing, in the most varied of configurations,
is combined with an equally extensive experience and enthusiasm for electronics
This results in a lot of Headroom and Reserves that allow you all the possibilities of
reinforcing and reproducing the natural sound of your instrument without having to enter into
any compromises. This applies equally to both electrical and acoustic instruments.
The range of equipment offers comprehensive and professional assistance to give
full Instrument optimum showcasing of your instrument and its sound on any stage and in all
appearance situations.
I wish you lots of enjoyment and relaxed successful performances with .
Michael Schäfer

07.09.2017
3
Copyright The copyright of all documentation provided with this product
remains with
Michael Schäfer
Sommerbergstraße 37
D-66346 Püttlingen.
This manual contains technical descriptions and drawings that
are not to be duplicated, spread, exploited or made accessible
to third parties neither in whole nor in part without our
permission. Any offences are punishable and shall impose
obligation to pay damages (lt. UWG BGB).
Validity The following documentation applies to all product types listed
on the cover page. Further variations are possible. The
information, details and data are presented without any warranty
or liability and is subject to change.
© 2017 by
Michael Schäfer
Sommerbergstraße 37
D 66346 Püttlingen
T: [phone]
F: [phone]
[e-mail]
www.realbass.de
Translation of Original Document

07.09.2017
4
Content
1. Important safety instructions........................................................................................5
2. General instructions before and during commissioning: ..........................................6
3. General Descriptions.....................................................................................................7
Phantom Power.......................................................................................................................7
Balanced and unbalanced Signalling......................................................................................7
Unbalanced Signalling.............................................................................................................7
Balanced Transmission...........................................................................................................8
dB............................................................................................................................................9
VU- display, Modulation display ............................................................................................10
H/L –changeover..................................................................................................................11
Gain.......................................................................................................................................11
PAD.......................................................................................................................................11
Phase....................................................................................................................................12
pre / post ...............................................................................................................................12
True Bypass..........................................................................................................................13
EQ.........................................................................................................................................13
High-Pass - Low-Pass - Band-Pass......................................................................................14
Parametric / Fully parametric.................................................................................................15
LOW-CUT..............................................................................................................................15
Compressor / Limiter.............................................................................................................15
Level......................................................................................................................................16
Threshold ..............................................................................................................................16
Insert (Send / Return)............................................................................................................17
Ground-Lift ............................................................................................................................17
Mute ......................................................................................................................................17
4. Technical Description..................................................................................................18
4.1 General points ...........................................................................................................................18
4.1 Brief instructions Front...............................................................................................................18
4.2 Brief instructions Back ...............................................................................................................20
4.3 Connection diagramm back side ...............................................................................................21
5. Commissioning............................................................................................................22
5.1 Initial Commissioning:................................................................................................................22
6. Technical data..............................................................................................................26
7. Optional accessories...................................................................................................27
8. Guarantee.....................................................................................................................28

07.09.2017
5
1. Important safety instructions
This document must always be read before commissioning for the first time and
must be kept available at the location of use. It contains fundamental instructions
that need to be observed during use. In addition, and in particular, the applicable
directives and regulations issued for the location of use must be observed.
The marks and symbols used, and their significance::
DANGER! WARNING! CAUTION!
This symbol is associated with safety instructions, the non-observance of which can
cause severe to fatal health dangers and injuries to persons. Observe the
instructions and act particularly carefully in these cases. Pass on all the safety
instructions to other users.
Warning of dangerous electrical power.
HINWEIS:
Ratschläge oder Hinweise, welche für die Nutzung und die sichere Verwendung
des Produkts hilfreich sind.
Hearing protection
The noise level must not exceed a value of LwA 85 dB. Provide protection with
appropriate hearing protection..

07.09.2017
6
2. General instructions before and during commissioning:
Danger of electrocution!
Do not carry out servicing and repairs of any kind yourself inside the housing.
Always use our trained service personnel or an authorised expert for servicing and
repairs.
Faulty connection of the product can lead to life-threatening injuries caused by the
electrical power. The product must only be connected to a plug socket that is
earthed!
Danger of hearing damage!
The amplifier can get very loud!
If you are constantly exposed to loud sounds, your hearing can suffer long-term
damage.
If you intend to use this amplifier at a high sound level for an extended period, we
recommend wearing appropriate hearing protection..
The manufacturer’s statements must always be observed.
The product must not be connected in a damp or wet environment. The power
cables must not be kinked. Protect the power cables from being stepped on
and close to the plug.
The product must be connected to a socket having an earth connection.
Never deactivate the earthing of the amplifier or its power cable! With three-
core lines, the 3rd. Core must always remain connected to the mains plug
socket and earth as an earth connection!
In the event of problems, and if you have any questions concerning the power
cable or mains plug, please consult an experienced electrician.
Isolate the amplifier from the power supply and pull out the mains plug before
cleaning and servicing
Clean the product only using a dry cloth.
Do not cover or close off the ventilation apertures.
Do not operate the product close to sources of heat, such as radiators, heaters
and ovens.
Use only genuine manufacturer’s accessories / fixing elements. Repairs must
only be carried out by trained expert personnel.
Repairs are only necessary if the product, a power cable, plug or components
are damaged. This applies also if liquids or objects have penetrated the
product or if the product has been exposed to rain and moisture.

07.09.2017
7
3. General Descriptions
Phantom Power
Microphones and other signal sources often require a separate power supply from a
battery, rechargeable battery or power supply. Today, this effort is avoided by supplying
connected signal sources with power via the signal cable (microphone cable etc.).
Therefore, a supply voltage is coupled to the signal wires of the connection cable in the
input of the mixing console. There is always a DC voltage which does not disrupt the
transmission of the audio signal as audio signals are always AC voltage.
The main principle of phantom-power is possible for balanced and asymmetrical
signalpath . A value of 48V for balanced signal source (microphone) is usual (rare is 24V).
By unbalanced source (radio-mikrophone, guitars, bass) establish 9V and 15V more and
more. The value available is not stabiliszed and fall with the cable-connected load aground
the consumer load (mikrophone, instrument). When there’s not cable-connected load, the
measured values should be in the declared effective range.
Balanced and unbalanced Signalling
This term requires no definition as it is used rather frequently throughout the description.
There are two types of signalling, namely balanced and unbalanced transmission.
Unbalanced Signalling
The benefit of this transmission type is the simpler input and output switching technology of
the individual devices. The disadvantage is its sensitivity to humming noises and other
interferences, which increases with each metre of cable length. This type is mostly used for
short transmission routes such as guitar, bass guitar or keyboard cables etc. The most
frequently used ports for this are 6,3mm jack ports.
What is most notable about the unbalanced transmission is the composition of the cables
used. They have a signal wire and a shield, which is simultaneously used as signal ground.

07.09.2017
8
Balanced Transmission
Balanced transmission is preferred for the application of very weak signal sources such as
dynamic microphones etc. It is also recommended to be used for longer cable lengths.
Its major benefit is its insensitivity to disruptions such as humming noises and interfering
signals i.e. line and environment related disruptions. Balanced transmission is less critical
with respect to line length.
Its disadvantage is the sophisticated switching technology for in- and output of the
separate devices. It used to be applied almost exclusively to sound studio and large stage
technology. Due to the drop in prices of electronic bulk sales, it increasingly captured the
market and is now commonly used in low-priced devices. The same applies to phantom
power being state of the art of current mixing consoles.
Mostly, the used plug connections are 3-pole XLR-connectors. The composition of cables
includes two signal wires and a mutual shield also being used as signal ground. The term
for this cable type is: Microphone cable.

07.09.2017
9
dB
dB -> Decibel.
Deci -> means a tenth.
Bel(l) -> was a physicist (telephone etc.), after whom this unit was named.
The unit dB has a logarithmic measure and represents the ratio of the input and output
voltage, or the input to the output sound level. The most relevant values with their effects in
the fields of sound and stagecraft can be seen in the following table
Value
(dB)
Ratio
Input Voltage
(mV)
Output Voltage (mV)
Volume change
3
1 to 1.414
200
282
Perceptible
6
1 to 2
200
400
easily perceptible
10
1 to 3.162
200
632
Double
12
1 to 4
200
800
Double
20
1 to 10
200
2000
Fourfold
40
1 to 100
200
20.000
Eightfold
-3
1.414 to 1
200
141
perceptible
-6
2 to 1
200
100
easily perceptible
-10
3.162 to 1
200
63
Halved
-12
4 to 1
200
50
Halved
-20
10 to 1
200
20
Quartered
-40
100 to 1
200
2
Eightfold reduction
The table shows that values less than 0 dB signify lowering (reduction, damping), and
values in excess of 0 dB signify lifting (amplification, increase). In addition, we can see that
volume perception and the voltage values are not in a linear relationship to each other. A
change of (+ or - +/-) 3 dB signifies a slight change from a purely acoustic point of view.
They are only easily perceptible above +/-6 dB. This is particularly important and must be
observed when using tone regulators (EQ), compressors and other effect devices.
The term 0 dB represents a particular situation. This basically means “Input = Output”. In
certain contexts, it also means an absolute value of 0.775 Veff at 600 Ω.
The principle of phantom power is possible both with balanced and unbalanced signal
paths. For balanced signal sources (e.g. microphones) a voltage of 48V is normal
(sometimes 24V), and for unbalanced sources (radio microphones, guitars, basses) a
voltage of 9V and 15V is gradually becoming established. The voltage available is not
stabilised and drops with the connected load by the consumer (microphone, instrument).
However, without a load (without a connected consumer), the values to be measured
should be within the stated ranges.

01.09.2016
10
VU- display, Modulation display
V= Volume
U=Units
The term VU meter comes from sound studio technology and is used designate a
measuring instrument that shows the current level of a signal source.
In order to prevent over-modulation (clipping, distortion) during modulation, the signal level
is displayed either on a pointer instrument or by a chain of LEDs. The scale on VU meters
of this type is either in % or in dB.
On mixer desks and amplifiers we often use just a single, generally red, LED for the
indication. This indicates an impending over-modulation or undesirable distortion of the
input signal by lighting up.
High-quality equipment include more more accurate displays. An adequate overview of the
incoming signal can be provided by three LEDs. A green one shows an input signal that
can be used, a yellow one indicate good modulation and a red LED indicates over-
modulation (distortion, clipping) of the input signal.
These input signals can be regulated using appropriate regulators / switches (gain
regulators or PAD switches) until just the green or yellow LEDs light up.
In an ideal situation, the indicated value on the VU meter is tapped off after the EQ (tone
regulation). Increasing the specific frequencies (treble, bass, mid-frequency) changes the
input signal in such a way that distortion (over-modulation) is produced, despite a good
setting on the GAIN at the output from the EQ. This should be shown on the VU meter to
allow you to reduce the input level accordingly.
Signal path
Your instrument produces a sound that is converted into an electrical signal by a pickup
head or microphone. This signal is directed via a cable to a mixer desk or an amplifier
where it is processed, modified and finally amplified.
All the locations in the movement of the signal from the instrument to the speaker are
refereed to as the signal path. The first stage or an amplifier / mixer desk is called the pre-
amplifier (preliminary stage). Here we process and amplify the input signal. After this we
have Low-Cut, compressor, EQ, loop-in paths and so on. The end stage and the speaker
or speakers come at the end of the chain
If we then do not use one of the components (for example the compressor or the EQ) then
this no longer forms part of the signal path
Ideally, it should be removed from the signal path completely. This occurs only with so-
called “True Bypass Switching”. The technically more simple variant, the Simple Bypass,
just separates off the output from the signal path and the input remains as a load in the
signal path.