Electronic Audio Experiments Longsword V4 User manual

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Technical Document
Longsword V4 Manual
Version 2
Last Revised: 10-Jan-21
John Snyder

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INTRODUCTION
Thank you for your purchase of the Electronic Audio Experiments Longsword!
This manual is an in-depth guide for properly using and enjoying your pedal.
But first, a little bit on the origins of the Longsword. This was the first EAE pedal,
conceived in the margins of my grad school notebook and designed during Boston’s
“snowpocalypse” in early 2015. At the time I lived in a basement apartment, and would
spend long nights breadboarding while the snow (literally) buried us in. The Longsword
was designed to meet a specific gap in my guitar rig at the time. As it turned out, my
needs were not as unique as I thought! The end result was a solid, general purpose
distortion pedal.
When playing distorted guitar in a band setting, my preferred style is to set a single
channel amplifier on the verge of breakup and push it a bit harder with a mix of pure
clean gain and some saturation inherent to whatever pedal(s) I’m using. Thanks to its
EQ, adjustable clipping/compression settings, and high output volume on tap, the
Longsword is well suited to this purpose and many others.
At its core, the Longsword is an op-amp drive with diode shunt clipping. An integrated
circuit called an operational amplifier (aka op amp) increases the signal amplitude
(loudness), and a pair of diodes limits the peaks. Cutting the peaks off of a signal
generates a spectrum of new harmonics, producing the distorted tones we all know and
love. This circuit block is found in hundreds of pedals (including the Distortion+, Rat,
OCD, even the venerable Klon Centaur/KTR) and is, in itself, not special.
The Longsword is made special because of the way its clipping amplifier is placed
between a series of other amplifiers and filters to precisely shape the sound. Many op-
amp-centric overdrive pedals sound good with one particular kind of guitar or amp, or
they have only one sound that they do well. Oftentimes, ones that sound good on their
own can drop out of the mix in a band setting. By taking advantage of the Longsword’s
dynamic range and powerful equalization, the player may easily defeat these
shortcomings.
Thanks for reading!
-John Snyder, EAE

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OPERATION
The Longsword requires an industry standard 9VDC center-negative supply with a
2.1mm barrel connection. We recommend (e.g. Truetone™, Voodoo Labs™,
Strymon™, Cioks™, etc). The Longsword draws 75mA of current when engaged.
The Longsword, as of Version 4.5, has a power supply protection circuit which shuts
down the pedal in the event of reverse polarity or a DC voltage greater than 9V. The
Longsword does not and cannot use batteries.
The Longsword uses soft-touch relay switching in a true bypass configuration. The relay
will default to the bypass state in the event of power loss.
Here’s my recommended procedure for dialing in the Longsword for the first time:
1. Begin with your amplifier set to its optimal clean tone.
2. Then, set all of the EQ controls on the Longsword to noon, set the drive and
level at minimum, ensure the boost is is off, and set all toggle switches up.
3. Turn on the pedal and slowly increase the drive and level until they are to your
liking. You’ll notice that the drive control introduces a natural high-end rolloff as it
is increased, reducing harsh upper harmonics. You’ll also notice lots of volume
on tap!
Next, it’s time to adjust the tone controls. With everything at noon, the Longsword has a
mostly flat response for guitar frequencies. The tone controls are more like a studio EQ
than a traditional stompbox control. The bands are fairly non-interacting, and small
changes can have a drastic effect. Thus we recommend adjusting the knobs gradually,
with small boosts and cuts away from noon. The low and high controls form a James-
Baxandall arrangement. This is a pair of passive shelving filters that cut frequencies
below or above a central crossover point. The mid control is a single band boost/cut
with a selectable center frequency using the SHIFT switch. Up on the toggle
corresponds to 1kHz (hi midrange), and down corresponds to 300Hz (low midrange).
Some notes on the EQ:
●If you boost both the low and high, you can get an effective mid scoop, and
conversely you can cut both to get an effective mid boost.
●The Longsword has a great deal of low end available, so a tighter tone can be
achieved by cutting the bass, particularly with an already overdriven amplifier.
●Don’t be afraid to scoop the low midrange (set the FREQ switch up), as it may
be a source of muddy tone with some guitars, especially on the neck pickup!

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The DIODE toggle switch will affect the dynamic response of the pedal, with settings
as follows:
●Switch up is medium compression via MOSFETs,which have high headroom
and a smooth transition into clipping which becomes fairly aggressive at higher
gain settings.
●Switch center removes diode compression altogether, which lets the natural
clipping of the op-amps shine through. This mode is recommended if you want
high dynamic range or are using the pedal as a clean boost/EQ into an already
driven amp.
●Switch down is high compression, using silicon diodes.
The differences between clipping modes are most apparent if you gradually turn up the
gain control to find the threshold of clipping. This will vary depending on the strength of
the input source (i.e. how hot your pickups are). We encourage experimentation!
Finally, the Boost Footswitch corresponds to the Longsword’s Boost knob. The boost
is placed before the main distortion circuit and has up to +20dB of gain and a low
frequency cut at 300Hz. This moderate low cut is ideal for tightening up the Longsword
at higher gain settings, as well as providing two distinct voicings for low and high gain.
In conclusion…
The Longsword is a very versatile distortion / overdrive pedal with a plethora of options
on hand and we hope it helps you dial in the exact tone you’re looking for, regardless if
you’re playing indie rock or doom metal. Thanks again!
CHANGELOG
Version 2
Manual release for Longsword V4.5
Version 1
Manual release for Longsword V4
www.electronicaudioexperiments.com