Tube-Town TT PoS100 User manual

PoS100
Kit PoS 100
Power Attenuator

PoS100 - version 2019
Content
Introduction....................................................................................................................................3
General Warning Informations.....................................................................................................4
Speci cation..................................................................................................................................5
Controls, Inputs and Outputs........................................................................................................5
Connection example......................................................................................................................7
Settings / Impedance....................................................................................................................8
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AVR ISP

PoS100 - version 2019
Introduction
From a technical point of view, the PoS100 is an adjustable attenuator which converts
excess electrical power into heat.
The PoS100 is specially designed for use with tube ampli ers for guitar and bass and gets
connected between the ampli er output and speaker input. The attenuator makes it
possible to drive the output stage into light clipping and regulate the excess output power
down with the PoS, making it an ideal addition for so-called “none master volume”
ampli ers, ampli ers with only one volume control for the preamp which usually have to be
set quite loud to get the desired overdrive.
The PoS can be universally connected to 4, 8 or 16 ohm amp outputs and offers in addition
to the volume control a range switch to set the basic attenuation (Lo / Hi). With the
“character” switch the behavior of the volume control can be switched between linear and
logarithmic. With some ampli ers the linear behavior works better whereas with other
ampli ers the logarithmic control suits better.
With the load selector switch the connected load has to be set. E.g. for an 8 ohm
loudspeaker cabinet the selector must be set to 8 ohms and the PoS must be connected to
the 8 ohms output of the amp. An impedance matching, e.g. 4 ohm speaker to 8 ohm
ampli er output, is not possible with the PoS. The loudspeaker output of the PoS offers a
second output jack, which is internally connected in parallel with the main output jack, this
makes it possible to connect two cabinets in parallel to the PoS. The correct load setting
must be taken into consideration: e.g. two 16 Ohms cabinets in parallel provide a total load
of 8 ohms. In this case the PoS selector must be set to 8 ohms and must be connected to
the 8 ohms output of the ampli er. Two 8 ohms cabinets in parallel result in a rtotal load of
4 ohms, in which case the 4 ohms output of the ampli er must be used and the PoS
selector must be set to 4 ohms.
The built-in signal lamp on the front serves as an optical feedback for the applied power.
The higher the power, the brighter it lights, even if the nal output volume of the PoS is set
very low.
On the backside is also an unbalanced line-out, where the ampli er signal can be taken for
further processing. The signal can be used for mixer consoles or for recording purposes
for example, however, depending on the application, a speaker simulation is still
necessary.
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PoS100 - version 2019
General Warning Informations
•Manufacturers and distributors are not liable or responsible for the consequences
of inappropriate use, installation errors or operation errors of this product due to
disregard of the manual. The building and installation should only be completed by
quali ed personnel.
•The contents of this manual are subject to change without notice.
•The attenuator can get hot after longer use!
•Always choose the matching impedance of the amp output, the cabinet and the PoS
(e.g. 8 ohm amp output, 8 ohm cab and 8 ohm at the impedance selector of the
PoS)
•Only use the attenuator with a valve amp!
•Attention: if the amp is used at maximum power and a high attenuation is dialed in
at the PoS the wear of the power tubes and the stress for the parts inside the amp
(e.g. the output transformer) will rise and can lead to damages
•Adjust the attenuation with care!
•To get the best sound results it is not always necessary to dial in maximum volume
on the amp, this is a common mistake
•Use the PoS always in combination with a speaker cabinet, the PoS is no dummy
load
•The maximum continuous power of 100 Watt must not be exceeded, otherwise it
may lead to damages or even destruction of the unit
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PoS100 - version 2019
Specification
Power: max. 100 Watt RMS
Attenuation: up to 100 %
Impedance: 4, 8 or 16 ohm
Line-Out: unbalanced, adjustable
Controls, Inputs and Outputs
front
1. Attenuation: range of adjustment up to 100 %
2. Signal lamp: illuminates in dependence of the input signal, with a low signal or
without any signal the bulb won't illuminate
3. Basic attenuation, select between Hi and Lo
4. Volume control characteristic, select linear or logarithmic
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PoS100 - version 2019
ack
5. Impedance selector: select the impedance of the amp output and the cabinet
impedance (4, 8 or 16 ohms)
6. Speaker output
7. Speaker output for a second cab (parallel, pay attention to the total impedance)
8. Input: connect the input of the PoS with the speaker output of the ampli er
9. Unbalanced line out: the amp output signal can be send to mixer consoles,
cab-sim, DI, etc.
10. Line-Level: adjust the level of the line-out signal
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PoS100 - version 2019
Connection example
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PoS100 - version 2019
Settings / Impedance
Amplifier Output Settings PoS 100 Speaker ca
4 ohm 4 ohm 4 ohm
(optional two 8 ohm cabinets if
the parallel output is used)
8 ohm 8 ohm 8 Ohm
(optional two 16 ohm cabinets
if the parallel output is used)
16 ohm 16 ohm 16 ohm
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