7Plug and connection assignment.................................................................................................... 24
8Protecting the environment.............................................................................................................. 27
Block-300B
3
General information
1 General information
This manual contains important instructions for the safe operation of the unit. Read and follow
the safety instructions and all other instructions. Keep the manual for future reference. Make
sure that it is available to all those using the device. If you sell the unit please make sure that
the buyer also receives this manual.
Our products are subject to a process of continuous development. Thus, they are subject to
change.
bass head
4
1.1 Further information
General information
On our website (www.thomann.de) you will nd lots of further information and details on the
following points:
DownloadThis manual is also available as PDF le for you to download.
Keyword search
Online guides
Personal consultation For personal consultation please contact our technical hotline.
Service
Use the search function in the electronic version to nd the topics of
interest for you quickly.
Our online guides provide detailed information on technical basics
and terms.
If you have any problems with the device the customer service will
gladly assist you.
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General information
1.2 Notational conventions
This manual uses the following notational conventions:
Letterings
The letterings for connectors and controls are marked by square brackets and italics.
Examples: [VOLUME] control, [Mono] button.
1.3 Symbols and signal words
In this section you will nd an overview of the meaning of symbols and signal words that are
used in this manual.
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bass head
General information
Signal wordMeaning
DANGER!This combination of symbol and signal word indicates an
immediate dangerous situation that will result in death or
serious injury if it is not avoided.
CAUTION!This combination of symbol and signal word indicates a pos‐
sible dangerous situation that can result in minor injury if it
is not avoided.
NOTICE!This combination of symbol and signal word indicates a pos‐
sible dangerous situation that can result in material and
environmental damage if it is not avoided.
Warning signsType of danger
Warning – high-voltage.
Warning – danger zone.
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Safety instructions
2 Safety instructions
Intended use
8
This device is intended to be used for the amplication of signals from musical instruments
with electromagnetic pickups. Use the device only as described in this user manual. Any other
use or use under other operating conditions is considered to be improper and may result in
personal injury or property damage. No liability will be assumed for damages resulting from
improper use.
This device may be used only by persons with sucient physical, sensorial, and intellectual
abilities and having corresponding knowledge and experience. Other persons may use this
device only if they are supervised or instructed by a person who is responsible for their safety.
bass head
Safety
Safety instructions
DANGER!
Danger for children
Ensure that plastic bags, packaging, etc. are disposed of properly and are not
within reach of babies and young children. Choking hazard!
Ensure that children do not detach any small parts (e.g. knobs or the like) from
the unit. They could swallow the pieces and choke!
Never let children unattended use electrical devices.
DANGER!
Electric shock caused by high voltages inside
Within the device there are areas where high voltages may be present. Never
remove any covers.
There are no user-serviceable parts inside.
Do not use the device if covers, protectors or optical components are missing or
damaged.
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Safety instructions
DANGER!
Electric shock caused by short-circuit
Always use proper ready-made insulated mains cabling (power cord) with a pro‐
tective contact plug. Do not modify the mains cable or the plug. Failure to do so
could result in electric shock/death or re. If in doubt, seek advice from a regis‐
tered electrician.
CAUTION!
Possible hearing damage
The device can produce volume levels that may cause temporary or permanent
hearing impairment. Over an extended period of time, even levels that seem to
be uncritical can cause hearing damage.
Decrease the volume level immediately if you experience ringing in your ears or
hearing impairment. If this is not possible, keep a greater distance or use su‐cient ear protectors.
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bass head
Safety instructions
NOTICE!
Risk of re
Do not block areas of ventilation. Do not install the device near any direct heat
source. Keep the device away from naked ames.
NOTICE!
Operating conditions
This device has been designed for indoor use only. To prevent damage, never
expose the device to any liquid or moisture. Avoid direct sunlight, heavy dirt, and
strong vibrations.
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Safety instructions
NOTICE!
Power supply
Before connecting the device, ensure that the input voltage (AC outlet) matches
the voltage rating of the device and that the AC outlet is protected by a residual
current circuit breaker. Failure to do so could result in damage to the device and
possibly injure the user.
Unplug the device before electrical storms occur and when it is unused for long
periods of time to reduce the risk of electric shock or re.
NOTICE!
Possible staining
The plasticiser contained in the rubber feet of this product may possibly react
with the coating of your parquet, linoleum, laminate or PVC oor and after some
time cause permanent dark stains.
In case of doubt, do not put the rubber feet directly on the oor, but use felt-pad
oor protectors or a carpet.
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bass head
3 Features
Features
This powerful bass head is characterized by the following special features:
n Compact, lightweight design
n Output power: 300 watt @ 4 Ω
n Class-D ICE power amp
n 5-band equalizer
n D.I. output with pre / post & lift / ground switch
n Input sensitivity switchable for active or passive basses
n Line input with volume control for rehearsing
n Headphones output
n Gigbag optionally available (item no. 194575)
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Installation and starting up
4 Installation and starting up
Unpack and carefully check that there is no transportation damage before using the unit. Keep
the equipment packaging. To fully protect the device against vibration, dust and moisture
during transportation or storage use the original packaging or your own packaging material
suitable for transport or storage, respectively.
Create all connections while the device is o. Use the shortest possible high-quality cables for
all connections. Take care when running the cables to prevent tripping hazards.
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bass head
5 Connections and operating elements
Front panel
Connections and operating elements
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15
Connections and operating elements
1 [INPUT]
Preamp volume control. If the [CLIP] LED lights up red, this controller must be turned counter-clockwise until the LED
turns green again. If some EQ band levels have been changed, re-adjusting the [ INPUT] control may be necessary.
2 [CLIP]
The LED lights up green when the device is turned on. It lights up red when the signal is clipping. Then turn the
[INPUT] control counter-clockwise until the LED turns green again.
Controls for raising or attenuating the bass / lower mids / mids / upper mids / treble
4 [OUTPUT]
Master volume control
5
3.5 mm jack output to connect head phones
6
3.5 mm jack input for connecting a line level player, e.g. MP3 player or mobile phone
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bass head
Connections and operating elements
7 [LINE]
Volume control for the input
8 [EQ]
Enables or disables the EQ. Slider control is only possible if the EQ is enabled.
9 [HI/LOW]
Switch for the sensitivity and impedance of the [IN]. When using passive instruments, this switch should be in the [HI]
position (not pressed), otherwise the input level is not sucient to fully drive the amplier. When using active instru‐
ments, this switch should be in the [LOW] position (pressed), otherwise clipping and thus a preamp overload can
easily occur, resulting in very disturbing-sounding distortions.
10 [IN]
1/4" jack socket to connect an electric bass
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Connections and operating elements
Rear panel
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bass head
Connections and operating elements
11 [POWER]
IEC chassis plug for mains connection with fuse holder
12 [D.I.]
Balanced direct-output with MIC level for connection to a mixer, directly to a PA system or for recording
13 [SPEAKER OUT]
Speakon speaker output for connecting suitable speaker boxes. The overall impedance of the connected load must
not fall below 4 Ω.
14 Housing fan
15 [PRE/POST]
This switch determines where the DI signal is tapped. In [PRE] position, the signal is tapped before tone control and
compressor, in [POST] position behind it.
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Connections and operating elements
16 [LIFT/GND]
This switch disconnects or connects the ground potential of the DI output and the device ground. In [LIFT] position
(released), the device ground is disconnected. This can possibly eliminate noise caused by ground loops, that may
occur when connecting the device to other grounded equipment. In [ GND] position (pressed), the device ground is
connected.
17 Mains switch to turn the device on and o
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bass head
6 Technical specications
Amp classClass-D ICE
Input impedanceHigh1.5 MΩ
Low32 kΩ
Line60 kΩ
Output impedanceD.I.470 Ω (balanced)
Frequency bandsBass50 Hz +/– 10 dB
Lower mids180 Hz +/– 10 dB
Mids660 Hz +/– 10 dB
Upper mids3 kHz +/– 10 dB
Treble12.5 kHz +/– 10 dB
Output powerSpeakermax. 300 W, 4 Ω minimum load
Technical specications
Signal-to-noise ratio> 80 dB (A-weighted)
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Technical specications
Total harmonic distortion (THD)< 0.5 %
Power consumption390 W
Operating supply voltage
Fuse5 mm × 20 mm, 4 A, 250 V, slow-blow
Dimensions (W × H × D)200 mm × 80 mm × 200 mm
Weight1.55 kg
Ambient conditionsTemperature range0 °C…40 °C
Further information
GigbagOptional (item no. 194575)
CompressorNo
LimiterNo
100 - 240 V 50/60 Hz
Relative humidity50 %, non-condensing
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Eects processorNo
External eects loopNo
Rack formatNo
Technical specications
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Plug and connection assignment
7 Plug and connection assignment
Introduction
Balanced and unbalanced trans‐
mission
24
This chapter will help you select the right cables and plugs to connect your valuable equip‐
ment in such a way that a perfect sound experience is ensured.
Please note these advices, because especially in ‘Sound & Light’ caution is indicated: Even if a
plug ts into the socket, an incorrect connection may result in a destroyed power amp, a short
circuit or ‘just’ in poor transmission quality!
Unbalanced transmission is mainly used in semi-professional environment and in hi use.
Instrument cables with two conductors (one core plus shielding) are typical representatives of
the unbalanced transmission. One conductor is ground and shielding while the signal is trans‐
mitted through the core.
Unbalanced transmission is susceptible to electromagnetic interference, especially at low
levels, such as microphone signals and when using long cables.
In a professional environment, therefore, the balanced transmission is preferred, because this
enables an undisturbed transmission of signals over long distances. In addition to the conduc‐
tors ‘Ground’ and ‘Signal’, in a balanced transmission a second core is added. This also transfers
the signal, but phase-shifted by 180°.
bass head
1/4" TS phone plug (mono,
unbalanced)
1/4" TRS phone plug (mono, bal‐
anced)
Plug and connection assignment
Since the interference aects both cores equally, by subtracting the phase-shifted signals, the
interfering signal is completely neutralized. The result is a pure signal without any noise inter‐
ference.
1Signal
2Ground, shielding
1Signal (in phase, +)
2Signal (out of phase, –)
3Ground
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Plug and connection assignment
Three-pole 1/8" mini phone jack
(stereo, unbalanced)
XLR plug (balanced)
1Signal (left)
2Signal (right)
3Ground, shielding
1Ground, shielding
2Signal (in phase, +)
3Signal (out of phase, –)
4Shielding on plug housing (option)
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bass head
8 Protecting the environment
Disposal of the packaging mate‐
rial
For the transport and protective packaging, environmentally friendly materials have been
chosen that can be supplied to normal recycling.
Ensure that plastic bags, packaging, etc. are properly disposed of.
Do not just dispose of these materials with your normal household waste, but make sure that
they are collected for recycling. Please follow the notes and markings on the packaging.
Disposal of your old device
This product is subject to the European Waste Electrical and Electronic Equipment Directive
(WEEE) in its currently valid version. Do not dispose with your normal household waste.
Dispose of this device through an approved waste disposal rm or through your local waste
facility. When discarding the device, comply with the rules and regulations that apply in your
country. If in doubt, consult your local waste disposal facility.