DE
A plucked string
creates a smooth
sound wave …
9v DC
22μF
Q1
3K3
Q2
Input Jack
… which increases
in amplitude as the
sound becomes louder.
100pF Q3
0.1μF
S1
10K log
22μF
0.1μF
1M
2K2
If an audio amplifier can’t
handle the amplitude, it
omits the upper and lower
extremes in a process
known as clipping. The
result looks and sounds
more like a square wave.
Output Jack
5K trimmer
100K
Q1, Q2, Q3: 2N3819 S1: Heavy-duty DPD T foot switch
WAVE CLIPPING The origin of distortion as a
defect that guitarists found desirable.
TUBE AMP DISTORTION EMULATOR
by Flavio Dellepiane, reprinted with
permission from redcircuits.com.
sound obtained from such a device has a peculiar
tone, much loved by most leading guitarists.”
Dellepiane offers dozens more schematics on
his site, developed and tested with a dual-trace
oscilloscope, low-distortion sine wave oscillator
(so that he can give audio devices a “clean” input),
distortion meter, and precision audio voltmeter.
The voltmeter and the oscillator were built from his
own designs, and he gives away their schematics
too. Thus his site provides one-stop shopping for
home-audio electronics hobbyists in search of a
self-administered education.
Guitarists today can choose from a smorgasbord
of effects, all of which can be home-built using plans
available online. For reference, Analog Man’s Guide
to Vintage Effects describes every vintage stomp-box and pedal you can imagine, while How to Modify
Effect Pedals for Guitar and Bass by Brian Wampler
is an extremely detailed guide for beginners.
Of course you can always take a shortcut by
laying down $200 for an off-the-shelf box such
as a Boss ME- 20, which uses digital processing
to emulate distortion, metal, fuzz, chorus, phaser,
flanger, tremolo, delay, reverb, and several more
effects, all in one convenient multipedal package.
Purists, of course, will claim that homebuilt
“doesn’t sound the same,” but maybe that’s not
the point. Some of us simply can’t feel satisfied till
we build our own stomp box and then tweak it, in
search of a sound that doesn’t come off-the-shelf,
and is wholly our own.
Got Stomp Boxes?
We’ve Got Mods
Since the ancient times, guitarists have modded
their amps and pedals in search of that killer tone
to rock your socks off. We asked DIY pedal experts
what’s hot in stomp box mods.
Visit makezine.com/15/stomp for:
» Top 4 Easy Stomp Box Mods from
Jack Orman of AMZFX
» Stomp box bibles
» Where to get parts
» Best web resources for DIY schematics and more
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