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TECHNICAL INFORMATION
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CIRCUIT
TwinStomp
BOOSTER
uses a modified version of the Mosfet Booster circuit developed by Jack Orman
www.muzique.com. This circuit is
widely known as the best for providing clean boost without colouring your
guitar's basic tone. It is not an overdrive circuit because it does not
produce artificial overdrive, however the gain from this circuit is able to
push valve amplifiers into creamy / crunchy overdrive sounds and is
therefore a must for valve amplifier owners.
The modifications allow for the provision of 2 independent boost output
settings and for the power source line to be switched. The adjustable gain boost channels are designed to give x1 to x5
Voltage Gain (0dB - 10db) on Channel 1 and x2 to x13 Voltage Gain (6dB
- 22.5dB) on Channel 2 as standard.
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COMPONENTS
TwinStomp
BOOSTER
only uses the highest specification
components purchased from reliable sources. Manufacturers data sheets are
available for all items including wiring and insulation materials.
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Semiconductors
Fairchild BS170 mosfet protected by zenor diode.
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Capacitors
High specification 1% polyester film capacitors are used for signal
transmission.
Ceramic capacitors are used for RFI suppression.
Aluminium film electrolytic capacitors capable of carrying well in excess of
the service voltages are used for smoothing and gain control.
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Resistors
Metal or carbon film resistors are used for voltage control.
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Potentiometers
Only
Alpha potentiometers are specified at present. Extremely smooth and
reliable.
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Jack Sockets
Only
Neutrik sockets are specified at present. Our experience has shown
these to be the most reliable.
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Switches
3PDT Stomp switches are Electro Harmonix (Taiwan Blue) which have been found to
be extremely reliable.
Power on-off switch is a
UL approved DPDT toggle with silver plated contacts and
parallel wired for reliability. Power on-off surges are limited by a
smoothing circuit.
The 9Vdc power connector/switch is rear mounted to allow quality soldering of the
connections out of the case.
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WIRING
All connections are
"Hand wired". There are no crimp or push-on connectors used in the
construction. Inter PCB wiring is supported by threading through
clearance holes in the PCBs to ensure that the connections are not under any
strain at any time. Wiring to switches and sockets is held firmly by
cable ties.
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SOLDERING
Lead free solder is used throughout and is specified on components.
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PCBs
The
TwinStomp
BOOSTER
incorporates two printed circuit
boards manufactured by a UK ISO9001:2000 approved supplier on FR4 glass material to provide rigid fixing for
components and reliable fixing for the two LEDs.
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CASE / ENCLOSURE
The case of
TwinStomp
products is investment cast to high
precision in non-magnetic stainless steel. This ensures that all
sockets and switches have excellent electrical contact with the case and
provides good screening against air borne noise.
The case is extremely
strong and provides mounting for non-slip rubber feet. These can be
removed to provide mounting holes for fixing the case to a pedal board.
The case is extremely
corrosion resistant with a finish that will last forever.
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UNIQUE BATTERY HOLDER
(Patent applied for GB0709168.9)
Because all
TwinStomp
effects pedals sound slightly
better when battery operated, with less stage clutter, we have developed a
unique method of accessing the 9 volt PP3 battery. On our effects your
battery can be replaced without removing the base of the case and without
requiring any tools. This means that your
TwinStomp
pedal can be permanently fixed to a
pedal board and you still have access to the battery!
Why do most effects
sound slightly better when battery powered? There are two main
reasons:
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Battery supply voltage although gradually reducing as the battery discharges
is very smooth. A 115Vac or 240Vac mains transformed 9Vdc supply will always have a
small amount of 50 or 60 Hz or harmonic ripple.
- We
recommend 9Vdc power supplies which have a fully isolated 9Vdc line and
0V return. On cheaper un-isolated power supplies you may have a double
earth return path. One earth path through the return screening of the guitar
lead, effects lead and guitar amplifier and a second earth path through the
return of the 9Vdc power supply. This may cause earth loop noise, which is
solved by using quality isolated power supplies.
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9 VOLT SUPPLY
Although we advocate
the use of
TwinStomp
products with 9 Volt PP3 battery we
do provide a 9 Volt dc supply input socket.
This socket can be
used with an external 9Vdc source, either battery or mains operated and
the PP3 internal battery does not need to be removed as the socket has an
internal switch to disconnect the battery. However please note - A
FULLY DISCHARGED BATTERY SHOULD NEVER BE LEFT IN THE BATTERY HOLDER AS
BATTERY LEAKAGE WILL DAMAGE YOUR
TwinStomp
CASE!
The
TwinStomp
BOOSTER
has smoothing in the 9 volt supply
circuit in order to eliminate On-Off switch noise and this also provides
additional smoothing for the Booster circuit.
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TESTING
Circuits are fully
tested twice, before and after assembly into the case. Every pedal has
a full functional test into a quality valve amplifier in addition to wave
form testing using a Function Generator, Oscilloscope and Digital Voltmeter.
We supply the main
test results on the Test Certificate supplied with each pedal.
Each pedal is permanently Serial Numbered and we keep full build
configuration and test results on our data base records.
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