The TWA Little Dipper LD-01 is an envelope-controlled formant filter pedal, a uniquely packaged take on filtering that responds to how hard you play rather than to a rocker pedal or a knob. According to TWA, the LD-01 is based on a classic '70s dual filter circuit, and the maker has dressed the theme throughout, right down to a deep sparkle blue case that Premier Guitar's reviewer described as resembling a clear and starry night sky1.
Controls, jacks and the LED indicator
The pedal's controls include an Ascension knob, which sets the filter threshold, and an Inclination selector with numbered positions that change where the filter sits in its sweep. The input and output are both mono ¼" jacks, and a true bypass stomp switch sits at the top of the panel1.
One detail sets the faceplate apart: between the control knobs and the stop switch, seven LEDs arranged in the shape of the Little Dipper constellation act as an input level indicator, which the reviewer called both artistic and useful1.
| Control | What it does |
|---|---|
| Ascension | Threshold control for the envelope-driven filter1 |
| Inclination | Selects the filter's sweep position1 |
| Stomp switch | True bypass on/off1 |
| Seven-LED dipper | Input level indicator1 |
What it sounds like
Because a formant filter shapes tone the way a mouth shapes vowels, the Little Dipper sits closer to vocal and wah territory than to a standard filter pedal. Premier Guitar's reviewer found that with Ascension turned up, it sounded, in their words, like wild filter sweeps controlled exclusively by touch, producing convincing Talk Box sounds from "Hair Of The Dog" tones to Frampton Comes Alive1.
"The further clockwise the Ascension was set, the more it sounded like somebody opening their mouth and talking with wild filter sweeps that were controlled exclusively by my touch."
With Inclination at position #1 and Ascension off, the reviewer found the tone similar to a parked wah, and switching between Inclination positions opened the filter up much like rocking a wah to a different sweep point1.
Power: 9V, with a 500 mA minimum
The Little Dipper can run from a 9-volt battery, but the battery must be "heavy duty" and have a full charge, or from a 9V input for external powering1. The catch is current: the pedal uses a voltage-doubling circuit, and power supplies of less than 500 mA do not power the unit properly1.
Many pedalboard power supplies deliver well under 500 mA per outlet. A quick call to Kevin at Godlyke, who handles TWA support, cleared up the power requirements for the reviewer, so a supply rated at 500 mA or more per outlet is the safe route1.
Versions and related TWA filters
The LD-01 is an envelope-controlled formant filter, a packaging TWA described as unique among filter pedals1. Where a standard envelope filter or a wah responds to the whole signal or to foot movement, the Little Dipper's combination of controls shapes the character of the sweep itself. With the Inclination control at position #1 and Ascension off, Premier Guitar's reviewer found the tone similar to a parked wah, with switching between Inclination positions opening the filter up much like rocking a wah to a different sweep point1.
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Questions
Is the TWA Little Dipper true bypass?
Yes. The Little Dipper LD-01 uses a true bypass stomp switch, so when the pedal is off, your guitar's signal passes through without the filter circuit loading it. That matters on a pedalboard where the Little Dipper sits alongside other always-on effects, since the bypass path keeps the dry tone intact when the filter is not engaged.
Why won't my power supply run the Little Dipper?
The Little Dipper uses a voltage-doubling circuit, and power supplies delivering less than 500 mA do not power the unit properly. Many standard pedalboard supplies split their output into 100 to 200 mA outlets, which is not enough here. Use a supply outlet rated at 500 mA or more, or a fully charged heavy duty 9-volt battery.
What circuit is the Little Dipper based on?
According to TWA, the LD-01 is based on a classic '70s dual filter circuit. TWA packaged it as an envelope-controlled formant filter, meaning the filters respond to your picking dynamics and shape the tone the way a human mouth shapes a vowel, which is why the reviewer found convincing Talk Box style sounds in it.
How much does the Little Dipper cost?
Premier Guitar's review listed the Little Dipper at a street price of $300. A successor, the Little Dipper 2.0, was later listed by Godlyke as a pre-order for late 2025 shipment, so pricing on the original may vary depending on availability.
Sources (1)
- TWA Little Dipper LD-01 Filter Pedal Review, Premier Guitar, 2009-12-04
