G.I. FUZZ
V
.2
Owner’s Manual
MI Audio Pty Ltd
PO Box 6426, North Ryde,
NSW 2113, Australia
www.mieffects.com
G’day!
Congratulations on purchasing the MI Effects G.I. Fuzz version 2. I sincerely
hope that you like your new pedal, and that it gives you years of great tone.
I’ve worked really hard on this one to produce something new and unique in
the world of fuzz pedals, and it is my hope that I’ve created something which
will be of great service to you tone wise.
The G.I. Fuzz is the younger brother of my other fuzz pedal, the Neo Fuzz.
The Neo Fuzz was the original design, meant to capture more of an old
school fuzz sound. I was a natural progression to then ask the question,
“What would the Neo sound like with high gain silicon transistors?” One
listen of my first prototype, and I had no choice but to call it the G.I. Fuzz.
You see if the Neo Fuzz is a bit purple and pink, a bit flowery and hippy, then
the G.I. is the opposite of that. It packs aggression on a military scale!
Introduction
I’ve found myself increasingly drawn to the sound of fuzz pedals. I’ve
traditionally been a bit of an overdrive man, and my pedal output thus far has
represented this. Despite my love for the sound of a good overdrive, there’s
just something about the sound of a great fuzz pedal which nothing else can
capture. I’ve grown really fond of that sound. Believe it or not, I think that
fuzz is a much more complex and tricky sound to get right compared to an
overdrive, and in fact there are many ‘tweaks’ and parameters to control in a
fuzz pedal. But a quick scan of the market quickly highlights two facts:
1)
Fuzz pedals tend to be very basic, often just a fuzz and volume
control. This is an accident of history since the first designs were
very simple and no-one really thought about adding lots of
features
2)
There’s been very little progress in the design of fuzz pedals in
the last 30 years. Most pedals out there are just a Fuzz Face or
Tonebender rehash.
I must confess, I toyed around with the idea of following the same path, but I
just couldn’t bring myself to do it. Surely there was a way forward? Surely
there was an opportunity here to unleash the hidden ‘tweakable’ potential of
a fuzz, allowing the guitarist to produce a whole bunch of different tones,
both old and new?
So to kick off the process, I began to analyse the various aspects of fuzz
pedals which contribute to the production of their sound. I isolated a few of
these, some more obvious than others:
1)
Transistors! There’s nothing which can create a great fuzz sound
like transistors. Whatever the type, silicon or germanium, an
overdriven transistor is the best way to produce a fuzz sound.
Nothing else should get in the way, no diodes, opamps, FETs.
This is vitally important. Obviously, the type and characteristics of
the individual transistor is very important.
2)
Symmetry or ‘bias’. The operating point of the transistor is a very
important factor in determining the sound of the fuzz. You can
think of the bias as the ‘neutral’ position of the circuit when there’s
no signal. If this point is in the middle of the ‘swing’ range, then
the signal can swing in equal amounts up and down. If it’s at
either extreme, then the signal can only swing a very small
amount in one direction, and then has a lot of room to swing in
the other direction. The ‘fattest’ sound is found when a circuit is
biased in order to have symmetrical swing. Accordingly, bias is a
very important factor for determining tone. It is actually one of the
reasons (whether people realise it or not) for people swapping out
transistors in fuzz pedals. By changing transistor gain, the bias
point is shifted (as well as changing the overall amount of fuzz
available)
3)
Pickup loading. This is a very important aspect in the creation of a
great fuzz sound, but not one that people usually think about.
Most fuzz pedals typically have very low input impedances. A
Fuzz Face for example, has an input impedance of the order of
10 kilo-ohms or so, which is very low. I don’t believe that this was
one of the design criteria for the creation of the first fuzz pedals. I
think it was just one of those historical ‘accidents’, but an accident
which nonetheless has contributed to the fuzz sound. This feature
is very important, not so much because it varies the signal
strength which hits the circuit, but because of the way that it
affects the frequency response of the guitar. As you decrease
input impedance, the first thing that goes is the top end of your
guitar sound. The low end is a lot more resilient. What you end up
with is a filtered, low pass signal, almost as if you’ve rolled off
some top end with the tone control. At the end of the day, this is a
good thing for a fuzz pedal. The major drawback though is that
the tone of the fuzz pedal is very heavily dependent on the pickup
that you’re using, since different pickups will behave differently for
a given load. For example, have you ever tried to use a high
output bridge humbucker with a fuzz pedal? It sounds awful! The
low input impedance is precisely the reason why this happens,
and why a fuzz is almost always used in conjunction with a low
impedance single-coil equipped guitar like a Strat.
The input circuit of V.2 has been improved on since the first GI
Fuzz was released to allow for a wider range of pickup loading.
So with these three principles in mind, I went about designing the G.I. Fuzz.
The following is a description of the features of the G.I. Fuzz:
Circuit
The G.I. Fuzz features 3 ultra high gain silicon transistors. In geekier terms,
they have transconductance about 3 times that of a typical silicon transistor,
and about 6 times as much as a germanium transistor. With so much gain,
the transistors clip very quickly. Also their clipping is a lot harder than
germanium transistors, meaning the sound produced has a lot more edge.
Fuzz
One of the things I never quite understood about a lot of fuzz pedals is just
how limited the gain range is. Well, from a circuit analysis perspective, this
limited range was due to the circuit design. But why not do something new
which would allow a greater range of low gain sounds? So one of the first
things I did was create a pedal with as wide a gain range as possible. In fact,
the G.I. Fuzz can go from nothing to all out fuzz. This unleashes a new
aspect of the fuzz circuit, namely its ability to create absolutely stunning low
gain sounds. I was amazed at just how good the low gain sounds were. You
may very well throw out your overdrive pedals and boosters when you hear
this thing at low gain settings. At very low fuzz settings, you get a clean
sound which bites when you dig in. It almost has a fender-like breakup. Turn
up the fuzz to 10 O’clock, and you have some gorgeous old-school blues
tones.
From 12 O’clock and up, you’re in traditional fuzz territory. There’s also an
internal gain trimmer for adjusting the overall amount of fuzz. With the
internal trimmer cranked, and the Fuzz up full, you have about 20db more
gain than a Fuzz Face. It’s literally like a Fuzz Face being driven by a 20db
booster! This is a serious amount of fuzz! Note that as a result of the huge
gain potential of the G.I. Fuzz, you might want to turn down the internal
trimmer in order to get a good range of low-gain sounds. If high gain’s your
thing, then keep the internal trimmer at 50% or more.
Load
One of the unique features of the G.I. Fuzz is the load control. This control
gives you precise control over just how much load your pickups see. For a
traditional fuzz face sound, keep the load control set to approximately 10
O’clock. This will keep that vintage low-pass or ‘muffled’ sound (in a good
way!). If you’re using humbuckers or high impedance pickups, try winding up
the load a bit to match your pickups. If you want to get that low gain
overdriveish tone I was talking about, keep the load control maxed to get the
brightest tone and fastest response from your pickups. One thing to keep in
mind is that the load control is very interactive with the fuzz control. If you
want to keep the same amount of gain, you need to turn up the fuzz control
as you turn down the load and visa-versa.
