The Spaceman Effects Delta II Cadet is a compact harmonic tremolo pedal with an all analog signal path. Where a standard tremolo raises and lowers the volume of your whole signal, the Delta II splits the signal into high and low frequency bands and modulates their amplitude in opposite directions, so one band swells while the other dips. Spaceman describes it as "a powerful optical harmonic tremolo with extensive tone shaping and an all analog signal path"1.
Its dual LFO design is the heart of the pedal. The LAG control adjusts the offset between the two LFOs from 0 to 180 degrees out of phase, which morphs the effect from traditional tremolo at one end to full harmonic tremolo at the other. That single knob is what lets one pedal cover both sounds1.
How the circuit works
The input signal is buffered, then split by a 2-pole state-variable filter into high and low bands. Each band is amplitude modulated in opposite directions using optical elements, then recombined. Spaceman says the optical elements "make for a smooth rise and decay, with a natural response"1.
This is the classic harmonic tremolo approach. As Delicious Audio explained when the original Delta II launched, "harmonic tremolo is achieved by splitting the input signal into high and low frequency bands, and amplitude modulating" them against each other, a design associated with smooth, phasey movement rather than a hard volume chop2.
The controls
The Delta II Cadet carries five controls: DEPTH, FREQ, RES, LAG and the VOICE toggle1.
| Control | What it does |
|---|---|
| LAG | Adjusts the offset of the dual LFOs from 0 to 180 degrees out of phase, morphing from traditional tremolo to harmonic tremolo1 |
| VOICE | Three-position toggle selecting which bands are modulated: High & Dry, High & Low, or Low & Dry1 |
| DEPTH | Sets modulation depth; at minimum on the original Delta II the filter works as a fixed tone shaper12 |
| FREQ | Sets the modulation rate1 |
| RES | Shapes the resonant character of the filter split1 |
The three VOICE positions change the pedal's character considerably:
- High & Low: modulates both bands against each other. Spaceman says it "provides a more liquid tonality especially useful for swirling phasey sounds"1.
- Low & Dry: modulates the low band against a dry signal, and "excels at dark throbbing low-end presence"1.
- High & Dry: modulates the high band against a dry signal, and "highlights top-end shimmer, and emphasises clarity and bite"1.
Spaceman's own description of the range is blunt: "Exploration of the DEPTH, FREQ, and RES controls will unearth filtery stabs, slithering vibrato, or robotic rhythms"1. In other words, pushed toward the extremes the pedal stops behaving like a polite tremolo and moves into filter, vibrato and rhythmic territory.
Power and connections
The pedal runs on 9 to 18V DC, negative center, through a standard 2.1mm jack. Spaceman describes the design as "18V capable for high headroom use cases," so players who want more clean sweep before breakup can run it at 18V12.
Spaceman's product page lists two different current draw figures, 19.5 mA in bypass and 45 mA elsewhere on the same page. The two disagree, so plan your power supply for the higher figure to be safe1.
The EXP/CV jack is a 0 to 5V DC TRS jack with over and reverse voltage protection, so a miswired expression pedal or control voltage source will not damage the input. On the original Delta II, the expression input works with expression pedals or CV sources and can control Depth or Rate12. Input resistance is 1Meg Ohm, which preserves high end with long cable runs into the pedal1.
History: the Delta II and the Cadet Series
Spaceman Effects, based in Portland, released the Delta II on October 30, 2022, a small form factor harmonic tremolo that Delicious Audio described as having "smooth organic tone" and "great swirling, phasey tones with endless rhythmic possibilities"2. The pedal belongs to the maker's Cadet Series, whose screen printed faceplates and raw metal enclosures set the series apart1.
The Delta II Cadet moves that circuit into the Cadet Series, which Spaceman says "brings Spaceman's signature sonic character to a wider audience through repeatable, SMD-based designs," with consistent availability, accessible pricing and everyday reliability1. The Cadet enclosures use screen printed faceplates and raw metal finishes rather than the painted and hand-finished look of Spaceman's through-hole releases, which is part of how the price lands at $179.001.
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Questions
What is the difference between harmonic tremolo and regular tremolo?
Regular tremolo raises and lowers the volume of the whole signal at once. Harmonic tremolo splits the signal into high and low frequency bands and modulates their amplitude in opposite directions, so as one band swells the other dips. The result is a smoother, phasey, swirling character rather than a straight volume pulse.
Can the Delta II Cadet run at 18 volts?
Yes. The pedal accepts 9 to 18V DC through a center negative 2.1mm jack, and Spaceman describes the design as 18V capable for high headroom use cases. Running it at 18V gives you more clean headroom before the signal path breaks up.
Does the Delta II Cadet take an expression pedal?
Yes. It has an EXP/CV jack, a 0 to 5V DC TRS jack that is protected against over and reverse voltage. On the Delta II, the expression input works with expression or CV sources and can be set to control Depth or Rate.
Is the Delta II Cadet analog?
Yes. Spaceman describes the Delta II as an optical harmonic tremolo with an all analog signal path. The modulation is done with optical elements, which the maker says give a smooth rise and decay with a natural response.
What is the difference between the Delta II and the Delta II Cadet?
The Cadet is the pedalboard-ready compact version in Spaceman's Cadet Series, which uses repeatable SMD-based designs for consistent availability, accessible pricing and everyday reliability. The original Delta II, released October 30, 2022, was Spaceman's first compact tremolo and shares the same harmonic tremolo circuit and LAG control.
Sources (2)
- Delta II Cadet: Harmonic Tremolo, Spaceman Effects
- Spaceman Effects Delta II Tremolo, Delicious Audio, 2022-10-30
