The TWA Side Step is a variable-state, tap-tempo low-frequency oscillator (LFO) in a stompbox, built to control practically any device with an expression input or a +5V control voltage source1. Instead of making sound itself, it plugs into the expression jack of another pedal, the "slave" pedal, and sweeps that pedal's parameter automatically. Delicious Audio describes the kinds of transformations this opens up: it can turn an envelope filter into an auto wah, a ring modulator into a whammy, a standard delay pedal into a pitch shifting delay, or a drive pedal into a modulating synth, and it adds tap tempo to a manual phaser2.
TWA announced the pedal in October 2019 as the SS-01 Side Step, at a $179 street price34. It is made in the USA3. As of late 2026 the maker's page lists it as out of stock, with a new production run to be announced1.
How it works and how you control it
The Side Step generates a low-frequency waveform and sends it out of its CTL jack into the EXP jack of the pedal you want to control, using a stereo 1/4" TRS cable1. That pedal's expression-controlled parameter, a filter sweep, delay time, pitch or whatever it exposes, then follows the waveform at the rate you set.
The LFO rate can be set three ways: by tapping the TAP SWITCH footswitch, by turning the onboard Rate pot, or by connecting an external expression pedal to the EXP jack1. Each control type overrides the others, so you can, for example, set a very high LFO rate with the expression pedal and then drop back to a slower tapped or dialed-in rate by touching either control1.
| Control | What it does |
|---|---|
| TAP SWITCH | Sets the LFO rate by tapping2 |
| Rate pot | Sets the LFO speed by knob6 |
| WAVEFORM SWITCH | Selects one of eight LFO waveforms1 |
| EXP JACK | Connects an external expression pedal (optional) with a stereo 1/4" TRS cable1 |
| CTL JACK | Connects to the EXP jack of the slave pedal with a stereo 1/4" TRS cable1 |
| BYPASS SWITCH | Bypasses the Side Step so the attached pedal works normally1 |
| EXP Thru switch | Lets the expression pedal control the slave pedal's standard EXP function, bypassing the Side Step without disconnecting it35 |
The EXP Thru switch is worth a closer look for anyone who already uses an expression pedal. With it engaged, your expression pedal controls the slave pedal directly, as it normally would, and the Side Step is effectively bypassed without anything being unplugged3. Flip it back and the Side Step's LFO takes over again.
The eight waveforms
The waveform rotary switch offers eight shapes3:
- Sawtooth
- Reverse Sawtooth
- Square
- Triangle
- Sine
- Peak
- Reverse Peak
- Random (sample/hold)1
The random option is a sample-and-hold function, stepping between values rather than sweeping smoothly, the kind of stepped, jumping motion associated with vintage synths. Pedal of the Day highlighted it as a favorite of one player, who reported using the Side Step mostly with the random waveform whenever a pedal on the board had an expression option1.
Power and bypass
The Side Step runs on external 9 volt DC power only, with no battery option, and requires a tip-negative, regulated supply of 100 mA or greater1. Tip-negative is the opposite of the center-negative standard on most modern pedals, so check your supply's polarity before plugging in. TWA recommends its PA-9 Power-All1.
For switching, the Side Step uses TWA's proprietary S3 "shortest send" system, a form of true bypass that combines electronic relays with a mechanical switch, and it defaults to bypass if power fails1. Premier Guitar's announcement also noted the pedal can be hard bypassed to run the slave device in its standard operating mode3.
Where the idea came from
The Side Step concept arose from discussions with Dweezil Zappa, who had envisioned a sample/hold function for the TWA Triskelion, TWA's drive pedal. TWA's tech's solution was to slave the Triskelion to an external LFO through its expression jack, which grew into a standalone, universal LFO pedal1. Pedal of the Day credited the idea to Zappa directly, calling it "a simple but ingenious little device that sprung from the mind of the marvelous Dweezil Zappa"6.
Used with the Triskelion specifically, the pairing offers three modes: manual control of the midrange frequency via expression pedal, LFO control of that frequency via the Side Step, or a fixed midrange frequency with the Triskelion on and the Side Step bypassed2.
What reviewers said
Pedal of the Day reviewed the Side Step in December 2019 and found it works with pedals like ring modulators, delays, envelope filters and more, including "setting some wild tap tempo stuff" with a phaser6. Their verdict:
"A simple but ingenious little device that sprung from the mind of the marvelous Dweezil Zappa, the Side Step™ is a revolutionary pedal that will twist and turn how you create music once you get it onto your board."6
Pedal of the Day, December 20196
Delicious Audio has also included the Side Step, at its $179 price, in a roundup of pedals for synths with CV in and out, noting it can control any pedal with an EXP/CV input using its eight waveforms4.
Videos
Godlyke Inc.
Cyberattack
Godlyke Inc.
Questions
Does the TWA Side Step run on a battery?
No. The Side Step runs off external 9 volt DC power only, and there is no battery option. You will need a power supply on your board to use it.
What power supply does the Side Step need?
TWA specifies any 9 VDC, tip-negative, regulated power supply of 100 mA or greater. The recommended supply is TWA's PA-9 Power-All. Note the tip-negative polarity, which is the opposite of most modern pedals.
Is the TWA Side Step true bypass?
It uses TWA's proprietary S3 "shortest send" switching, a form of true bypass that combines electronic relays with a mechanical switch. It defaults to bypass if power fails, so the attached pedal keeps working normally.
What waveforms does the Side Step have?
Eight, selected by a rotary switch: sawtooth, reverse sawtooth, square, triangle, sine, peak, reverse peak, and random, which is a sample and hold function that jumps between random values.
Can I use an expression pedal with the Side Step?
Yes. The EXP jack accepts an external expression pedal connected with a stereo 1/4 inch TRS cable, and it sets the LFO rate. An EXP Thru switch lets the expression pedal control the slave pedal's normal expression function instead, without unplugging anything.
Is the TWA Side Step still in production?
As of late 2026 the maker's page lists the Side Step as out of stock, with a new production run to be announced. It was originally released in October 2019 as the SS-01 Side Step.
Sources (6)
- TWA Side Step, Godlyke Distributing, Inc.
- TWA Side Step LFO Expression Pedal, Delicious Audio, 2021-12-21
- TWA SS-01 Side Step Universal Tap-Tempo LFO Launch, Premier Guitar, 2019-10-29
- The Best Pedals For Synths With CV In/out In 2022, Delicious Audio, 2020-10-01
- TWA releases SS-01 Side Step Universal Tap-tempo LFO, MusicPlayers.com, 2019-10-23
- TWA Side Step™ Universal Variable State LFO, Pedal of the Day (pedal-of-the-day.com), 2019-12-24
Dweezil Zappa
