Page 126 - FLIPMAG.NET

DIY WORKSHOP
1
he demand for Klon Centaurs has
driven prices into the stratosphere.
All of the originals were hand-built
T by Bill Finnegan, who joined forces
with a couple of MIT engineers to design
this most-revered boost/overdrive pedal.
By stompbox standards, it’s a complex and
highly original circuit, and after producing
about 8,000 units between 1994 and 2000,
Finnegan decided he’d had enough.
With demand so high and supply cut off,
the inevitable happened: a mini-industry
of Klon cloners has sprung up over the
past two decades. But it’s only Malaysia’s
Ceriatone that has gone to the trouble of
recreating Finnegan’s original enclosure and
PCB layout – and the result is the Centura
Professional Overdrive.
Ceriatone offers various options. You
can buy the printed circuit board and
enclosure or get the PCB fully assembled.
You can also buy the pedal pre-built, or
a full kit with a variety of finishes and
graphics. I can’t resist the chance to build
my own and learn more about this fabled
circuit in the process.
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BOUTIQUE BUILDING
Ceriatone’s Centura kit is an advanced
build but only because the amount of
components invovled is higher than usual
for a DIY overdrive, and the instructions
don’t hand everything to you on a plate.
You’ll need to read them carefully and
do some planning for final assembly.
Choices need to be made from the get-
go too. Though the Klon Centaur circuit
remained almost unchanged throughout its
production run, Finnegan did tweak a few
component values. In 1995, two of the 1uF
capacitors in the signal path were increased to
4.7uF to let more low frequencies through,
and a 15k resistor was added to ‘sweeten’ the
midrange. Three resistors were also added
to reduce popping from the footswitch,
but they have no effect on the sound.
The manual lays all of this out and
identifies the components on clearly drawn
diagrams. Having the anti-popping resistors
is a no brainer but I’m less sure about the
extended lows and bolstered midrange.
Since the vast majority of Klon Centaurs
have the later circuit, I decide to try it.
As with any kit, the first task is to sort
through the components and verify that
everything on the list is present. I prefer to
work from printed instructions, so I run a
length of masking tape along the left-hand
side of the page adjacent to the resistor list.
Even if you know your colour codes, I
recommend measuring each resistor using a
multimeter. Once I’ve identified and verified
a resistor, I place one of its wires under the
masking tape alongside its position on the
list. This helps to keep things organised and
means you only have to sort them out once.
Electrolytic capacitors are not difficult
to identify, because the values are written
on the casings. The film capacitors have
three-digit numerical codes with the value
and a multiplier, so you may need to find an
online capacitor code table for clarification.
Beware of the small yellow 1uF capacitor
too – it’s polarised, with one leg bearing
a tiny plus sign printed next to it.
The PCB is compact but the component
positions and values are plainly marked. I
solder the three integrated circuit sockets,
using an small-tipped iron set to 350 celsius.