STOMPSCHOOL
The Truth About Bypass, Pt. 1
What’s up pedal people? The summer
semester of “Stomp School” is still in session, so get your pens, pencils, notebooks
and patch cables ready – the price of tuition
is paying attention to your tone. This month
we’re going to begin a discussion of the
various methods of bypassing effects pedals. One of the biggest buzzwords that gets
thrown around regarding stomp pedals is
“true bypass.” The majority of new, boutique
effects these days feature
true bypass switching as
a matter of course. Going
back 10 to 15 years ago,
I can recall few guitarists
that even considered the
effect of bypass switching on their tone. These
days it seems all except
the most casual players
are familiar with the term
true bypass. In fact, it
has gotten to the point
where many players insist
that all their pedals must
have true bypass switching, without really understanding what it is and
why they need it. So let’s
start with an explanation of true bypass from
my esteemed colleague,
Analog Mike:
Electro-Harmonix, most wahs, almost any
pre-1980 pedal except a Fuzz Face – you
may lose some high-end when it’s off due to
your signal bleeding into the components.
If you have an ‘electronic switch’ pedal, it is
probably designed well enough that even
though it is not true bypass you will not lose
any signal, as the signal is properly buffered
through active circuitry, even when off.”
they are not ‘true bypass,’ this type of effect,
if properly designed, will not load or affect
your signal much when the effect is off. They
can actually help your signal when off. For
example, if you use a long patch cord, they
act as a signal buffer.
“Most vintage MXR and Electro-Harmonix
pedals are not true bypass either, but do use
a direct wire to bypass the
signal when they are off
(they will pass the signal
in the off position without
a battery). But nearly all
MXR and Electro-Harmonix
effects use a single pole,
double throw (SPDT) switch
with only three terminals, as
it is cheaper than the six-ter-
minal double pole, double
throw (DPDT) switches.
These are not true bypass.
This means that when the
effect is off, the guitar signal
will go directly to the output
jack but is still connected to
the input of the effect’s cir-
cuitry. Some of the signal is
lost this way, a bit like turn-
ing down your tone control
on your guitar.”
“True bypass means when
a pedal is off, the signal goes in the input
jack and out the output jack without touching any components – resistors, capacitors,
op-amps, etc. You cannot check for this by
pulling out the battery, as you will still get a
signal out of, for example, an old wah, even
though it is not really true bypass (the circuit
still is attached to some components when
off). Let’s call this type of effect a ‘stomp
switch’ pedal – it uses a round stomp switch
to turn it on and off, and it passes signal
through even with no battery. Another type
of effect is the Ibanez or BOSS-type with
electronic switching, not a normal looking
stomp switch. These do not have any sound
without a battery. Call these an ‘electronic
switch’ pedal.
Only effects that skip all of the electronics when off
can be considered “true” bypass
Thanks Mike! Although many guitarists may
be somewhat savvy when it comes to electronics, others are probably not, so it may
not be immediately apparent what type of
switching is being used in their favorite pedals. Let’s see if Mike can clear that up for us:
Thanks again, Mike. As
an aside, I would add that
these days most of your
favorite boutique stomp-
boxes use a 3PDT switch to allow for the
addition of an LED, as well as true bypass
switching. Well, that’s a wrap for now. Check
back with us next month when we’ll continue
discussing the “Truth About Bypass.” Until
then, keep on stompin’!
“If you have a ‘stomp switch’ type pedal
without true bypass – all MXR pedals, most
“In Ibanez and BOSS-type pedals, which
use electronic switching, the signals do not
go straight through a wire when they are
off; they go through some components (
op-amps and/or transistors). You can tell effects
of this type because you will get no signal
through when the battery is out. Also, they
do not use a stomp on/off switch, but a
momentary contact switch, which switches
the signal electronically rather than mechanically like the old stomp switches. Although
Tom Hughes
(a.k.a. Analog Tom) is the owner and proprietor of For
Musicians Only ( formusiciansonly.com) and author of
Analog Man’s Guide To Vintage Effects. For Musicians
Only is also the home of the FMO Gear Shop.
Questions or comments about this article can be sent
to: stompschool@formusiciansonly.com.
Analog Man
( analogman.com) is one of the largest boutique effects
manufacturers and retailers in the business, established by “Analog” Mike Piera in 1993. Mike can be
reached at AnalogMike@aol.com.
