The Quasar Quantum was a phaser pedal from Subdecay, built as an all analog, VCA based design. Subdecay described it in typically playful terms: "This all analog VCA based phaser entangles your guitar signal with quantum magic." The pedal is no longer in production, so it now exists only on the used market1.
The controls: Shape, Speed and Regen
The Quasar Quantum keeps its front panel to three knobs, and each one does more work than the usual phaser layout.
| Control | What it does |
|---|---|
| Shape | Selects six different LFO shapes to modulate the phaser1 |
| Speed | Controls the phaser modulation speed, from "slow and orbital to accelerated quantum vibrations"1 |
| Regen | Controls the feedback and intensity of the effect1 |
Regen is the knob that shapes the character of the effect. Subdecay describes its range as going from subtle vibe to the edge of oscillation, and notes that past the 2:00 mark the effect starts to cut the dry signal and pushes the phaser peaks to near oscillation1. In other words, low settings behave like a conventional phaser, while high settings take the pedal into a more aggressive, unstable territory that some players seek out deliberately.
The six LFO shapes
The Shape control is what sets the Quasar Quantum apart from a standard single-mode phaser. Instead of one fixed modulation wave, it offers six, each with a distinct character1:
- Sine: Sounds great for vibe tones, especially at medium to higher speeds1
- Triangle: The classic LFO shape for most phasers, offering smooth balance modulation1
- Random sample/hold: Completely random step modulation1
- 8 step: Similar to the random LFO, but arranged in an 8 step triangle sequence1
- 16 step: Similar to 8 Step, but a longer sequence1
- Triangle/Square: A slow triangle with a faster square LFO as well, mixing jagged steps with a more traditional sound1
The stepped shapes (random sample/hold, 8 step and 16 step) move the phaser in discrete jumps rather than smooth sweeps, which produces the choppy, sequenced modulation that a plain sine or triangle wave cannot deliver. Triangle is the shape most players will recognize, since Subdecay calls it the classic LFO shape for most phasers1.
Power, connections and build
The pedal runs on a regulated 9VDC to 18VDC adapter with a negative center 2.1mm barrel style plug, and current draw is less than 100mA. A power supply is not included1.
Subdecay warns that if you use a "daisy chain" power supply, all other pedals on the chain MUST be negative ground. The pedal also accepts up to 18VDC, so check what your supply delivers before plugging in.
On the I/O side, the input impedance is 1M and the output impedance is less than 1K1. Bypass switching is handled by 3PDT switches for true bypass1. The pedal measures 4.375 × 2.375 × 2.25 inches, weighs 12 oz, and sits in a die-cast metal enclosure that Subdecay describes as built for durability. It carried a three-year limited warranty and was hand made in Oregon1.
Where it sat in the Quasar family
The Quantum was one of several phasers Subdecay built under the Quasar name. The family also includes the Quasar Phaser, the Quasar DLX, the Quasar DLX Deluxe Phaser and the Quasar Phase Modulator V.4. With the Quantum itself out of production, players looking for its combination of analog VCA phasing and switchable LFO shapes will need to find one secondhand1.
Videos
Subdecay
Prymaxe
Brett Kingman
Questions
Is the Subdecay Quasar Quantum true bypass?
Yes. Subdecay states the Quasar Quantum uses 3PDT switches for true bypass switching, so the pedal passes your guitar signal untouched when it is off. It is built into a die-cast metal enclosure for durability and was hand made in Oregon.
Is the Subdecay Quasar Quantum analog?
Yes. Subdecay describes it as an all analog, VCA based phaser. A VCA, or voltage controlled amplifier, is the circuit element the pedal uses to move the phase shifting stages, rather than a digital processor.
Does the Subdecay Quasar Quantum come with a power supply?
No. Subdecay notes that a power supply is not included. The pedal runs on a regulated 9VDC to 18VDC adapter with a negative center 2.1mm barrel plug, and current draw is less than 100mA.
Is the Subdecay Quasar Quantum still in production?
No. Subdecay's product page lists the Quasar Quantum as no longer in production, so it now turns up only on the used market.
What are the six LFO shapes on the Quasar Quantum?
The Shape control selects six LFO shapes: Sine, described as good for vibe tones at medium to higher speeds; Triangle, the classic smooth phaser shape; Random sample/hold, completely random step modulation; 8 step, an 8 step triangle sequence; 16 step, a longer version of the 8 step sequence; and Triangle/Square, a slow triangle mixed with a faster square LFO.
Sources (1)
- Quasar Quantum, Subdecay, 2022-07-15
