thomann Harley Benton PA-250 User manual

PA-250
Power Attenuator
User Manual

Thomann GmbH
Hans-Thomann-Straße 1
96138 Burgebrach
Germany
Telephone: [phone]
Internet: www.thomann.de
21.10.2022, ID: 510412 (V4)

Table of contents
1 General information................................................................................................................................. 5
1.1 Further information........................................................................................................................... 6
1.2 Notational conventions.................................................................................................................... 6
1.3 Symbols and signal words............................................................................................................... 7
2 Safety instructions..................................................................................................................................... 9
3 Features....................................................................................................................................................... 11
4 Connections and controls................................................................................................................... 12
4.1 Connection options......................................................................................................................... 15
5 Technical specications....................................................................................................................... 16
6 Plug and connection assignment.................................................................................................... 18
7 Cleaning....................................................................................................................................................... 20
8 Protecting the environment.............................................................................................................. 21
Table of contents
PA-250 3
Power Attenuator

4PA-250
Power Attenuator

1 General information
This user manual contains important information on the safe operation of the device. Read and
follow all safety notes and all instructions. Save this manual for future reference. Make sure
that it is available to all persons using this device. If you sell the device to another user, be sure
that they also receive this manual.
Our products and user manuals are subject to a process of continuous development. We there‐
fore reserve the right to make changes without notice. Please refer to the latest version of the
user manual which is ready for download under www.thomann.de.
General information
PA-250 5
Power Attenuator

1.1 Further information
On our website (www.thomann.de) you will nd lots of further information and details on the
following points:
Download This manual is also available as PDF le for you to download.
Keyword search Use the search function in the electronic version to nd the topics of
interest for you quickly.
Online guides Our online guides provide detailed information on technical basics
and terms.
Personal consultation For personal consultation please contact our technical hotline.
Service If you have any problems with the device the customer service will
gladly assist you.
1.2 Notational conventions
This manual uses the following notational conventions:
General information
6PA-250
Power Attenuator

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.
Signal word Meaning
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.
Letterings
General information
PA-250 7
Power Attenuator

Warning signs Type of danger
Warning – high-voltage.
Warning – danger zone.
General information
8PA-250
Power Attenuator

2 Safety instructions
This device is used to attenuate the output level of guitar amps. Use the device only as
described in this user manual. Any other use or use under other operating conditions is consid‐
ered 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 sucient 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.
Safety
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.
Intended use
Safety instructions
PA-250 9
Power Attenuator

CAUTION!
Possible hearing damage
With loudspeakers or headphones connected, the device can produce volume levels that may cause temporary or permanent
hearing impairment. Do not operate the device permanently at a high volume level. Decrease the volume level immediately if you
experience ringing in your ears or hearing impairment.
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. Only operate the device within the ambient conditions specied in the chapter
‘Technical specications’ of this user manual. Avoid heavy temperature uctuations and do not switch the device on immediately
after it was exposed to temperature uctuations (for example after transport at low outside temperatures). Dust and dirt inside can
damage the unit. When operated in harmful ambient conditions (dust, smoke, nicotine, fog, etc.), the unit should be maintained by
qualied service personnel at regular intervals to prevent overheating and other malfunction.
NOTICE!
Damages caused by the connection to an enabled amplier
Always connect the device to a disabled amplier, otherwise the amplier may be damaged.
NOTICE!
Possible staining
The plasticiser contained in the rubber feet of this product may possibly react with the coating of your surface and after some time
cause permanent dark stains. In case of doubt, do not put the rubber feet directly on the surface and use a suitable underlay if neces‐
sary, i.e. felt pads or similar.
Safety instructions
10 PA-250
Power Attenuator

3 Features
Power soak for tube ampliers, ideal for use in rehearsal rooms, recording studios and on
stage.
nPower consumption: max. 250 W
n8 Ω option, 16 Ω option
nPower supply via amplier
nInputs: amplier, optional power adapter
nOutputs: PA equipment/mixing console (low impedance), line, speaker
nControls: speaker level, line level, ne level
nSilent fan
Features
PA-250 11
Power Attenuator

4 Connections and controls
ö '$ %# &
( + ,- /) * . 0
Connections and controls
12 PA-250
Power Attenuator

1[BY PASS] | toggle switch for disabling the power reducer. The LED lights.
The signal is output just as loud as if the speaker was connected directly to the amplier.
2[POWER (db)] | rotary control for adjusting the volume of the signal at the speaker output when the device is working as a
power attenuator.
Turn this control clockwise to reduce the volume of the output signal in steps of 2…3 dB. Turn the control to ‘–15’ to
enable the rotary control [FINE].
3[POWER] | status LED. The LED lights up when the device is working as a power attenuator.
4[8 Ω / 16 Ω] | rotary control for setting the impedance. The corresponding LED lights.
The impedance must be set to the same value on the Power Attenuator, on the connected amplier and on the speaker.
5[FINE] | rotary control for adjusting the eective signal volume at the speaker out. The [FINE] LED lights up when the [FINE]
control is activated (see point 2).
Turn the control clockwise to reduce the output signal volume in steps of 4…5 dB up to ‘–∞’ (no sound). If you turn the
control to ‘–15’ , the eective volume is –15 dB less than the not-attenuated volume.
6[LOAD] | toggle switch for operating mode selection
In the upper position, the device works as a load box (load resistance for the amplier, without signal at the speaker output)
and the [LOAD] LED lights up. In the lower position, the device works as a power attenuator (power reducer) and the
[POWER] LED lights up.
7[BALANCED OUT] | low-impedance XLR output for connecting PA equipment or a mixing console
8[GND LIFT] | switch for disconnecting the grounding to avoid unwanted hum noises caused by ground loops
Connections and controls
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Power Attenuator

9[LINE OUT] | Line output for connecting PA equipment or a mixing console
The LED [OUT] lights when PA equipment or a mixing console is connected.
10 [LINE LEVEL] | rotary control for adjusting the signal volume at the line out
11 [POWER] | input socket for an optional power adapter
If you want to run the LEDs and the fan permanently stable, you can use an optional power adapter as power supply.
12 [AUX POWER] | status LED. LED lights when the device is operated via an optional power adapter.
13 [INPUT FROM AMP] | input socket for connecting an amplier
The impedance must be set to the same value on the Power Attenuator and on the connected amplier.
Connect the device always to the disconnected amplier, otherwise the amplier may be damaged.
The device is powered by the amplier. The more powerful the amplier, the faster the fan runs and the brighter the LED
lights up.
14 [8 Ω / BY PASS / 16 Ω] | status LED. The LED lights when the function is activated.
15 [OUTPUT FROM SPEAKER] | output socket for connecting a passive speaker box
Connections and controls
14 PA-250
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4.1 Connection options
Amplier
Guitar
to input to input
to speaker
(8 W/ 16 W)
from output
(8 W/ 16 W)from output
Connections and controls
PA-250 15
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5 Technical specications
Max. input power handling 250 W
Input connections Amp 1 × 1/4" jack socket
Power supply Input socket for an optional power adapter
Input impedance 8 Ω, 16 Ω
Output connections PA equipment/mixing console 1 × XLR (low-Z), balanced
Line 1 × 1/4" jack socket
Speaker 1 × 1/4" jack socket
Voltage supply via amplier
optional: external power adapter, 100 - 240 V 50/60 Hz
operating voltage: 9 … 24 V , 300 mA, centre negative
Dimensions (W × H × D) 235 mm × 88 mm × 179 mm
Weight 2.7 kg
Ambient conditions Temperature range 0 °C…40 °C
Relative humidity 20 %…80 % (non-condensing)
Technical specications
16 PA-250
Power Attenuator

Noise reduction no
DI output yes
Speaker simulation no
Dummy Load yes
Further information
Technical specications
PA-250 17
Power Attenuator

6 Plug and connection assignment
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°.
Since the interference aects 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.
Introduction
Balanced and unbalanced trans‐
mission
Plug and connection assignment
18 PA-250
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1 Signal
2 Ground, shielding
1 Signal (in phase, +)
2 Signal (out of phase, –)
3 Ground
1 Ground, shielding
2 Signal (in phase, +)
3 Signal (out of phase, –)
4 Shielding on plug housing (option)
1/4" TS phone plug (mono,
unbalanced)
1/4" TRS phone plug (mono, bal‐
anced)
XLR plug (balanced)
Plug and connection assignment
PA-250 19
Power Attenuator

7 Cleaning
Clean the externally accessible device parts regularly. The frequency of cleaning depends on
the operating environment: wet, smoky or particularly dirty surroundings can cause more
accumulation of dirt on the device parts.
nClean with a soft dry cloth.
nStubborn stains may be removed with a slightly damp cloth.
nNever use cleaners containing alcohol or thinner.
The fan grids of the device must be cleaned of any contamination, such as dust, etc. on a reg‐
ular basis. Before cleaning, switch o the device and disconnect mains-operated devices from
the mains. Only use pH-neutral, solvent-free and non-abrasive cleaning agents. Clean the unit
with a slightly damp lint-free cloth.
Device parts
Fan grids
Cleaning
20 PA-250
Power Attenuator