The Parabola is a tremolo pedal from Caroline Guitar Company, built as an analog, solid state, transistor based circuit. Caroline bills it as your rig's new "tremolo channel", and it offers two ways to modulate your signal: the classic, dramatic amplitude modulation (AM) you might expect from a tremolo, or a filtered modulation (FM) that the maker describes as subtle, beautiful, and less invasive on your playing. The speed and depth ranges were modified, in Caroline's words, to match and go beyond those from your favorite classic amps.1
What it does to your sound
A tremolo raises and lowers the volume of your signal at a set speed and depth, and the Parabola does that with a transistor based low frequency oscillator rather than a digital chip. Caroline adapted the LFO and its distinctive waveform from the maker's favorite "West German" device, describing it as "deliciously sloshy", and modified its speed and depth to cover classic amp tremolo territory and beyond.1
The two modes split the work differently:
- AM (amplitude modulation): the classic, dramatic tremolo effect, the kind of volume pulsing players expect from a vintage amp tremolo1
- FM (filtered modulation): a subtler treatment that Caroline says is less invasive on your playing12
Guitar Pedal X's reviewer, Stefan Karlsson, heard the difference clearly: "The Filtered mode is subtler, with a different timbre."3
Overdrive and boost on board
The Parabola is not only a tremolo. Caroline added pre and post effect gain stages for both overdrive and volume boost, so the pedal can drive an amp or lift a quiet signal in addition to modulating it.1 That gain staging is why Karlsson described the Pawnshop Edition as a "higher gain, preamp assisted, amp style tremolo".3 If you want to compare it against dedicated gain pedals, see Overdrive Pedals and Boost Pedals, or for other ways to move your volume, see Tremolo Pedals and Vibrato Pedals.
Versions and where it is made
Two versions exist, the standard Parabola and the Pawnshop Edition. The Pawnshop Edition adds Fast/Slow ranges and a Havoc footswitch for maximum Depth and Speed.3 It is a limited run: Karlsson reported in May 2026 that it was "Long since sold out on the Caroline Guitar site", with a handful of units remaining on Reverb.com at $219.31 Details on that version are on the Parabola Pawnshop Edition page.
Every Parabola is dreamed, designed and created at Caroline's small batch distortery in Columbia, S.C.2 Delicious Audio's Paolo De Gregorio covered the pedal when it was the company's latest release in April 2018.4
Power
The Parabola runs on 9V DC, center negative, the standard for pedalboard supplies.2
Because the Parabola is an analog, transistor based circuit, a clean, regulated 9V DC center negative supply matters. A noisy or unregulated supply can introduce hum or instability into the modulation.
Videos
The Pedal Zone
Reverb
collector//emitter
Questions
What is the difference between AM and FM mode on the Parabola?
AM is the classic, dramatic amplitude modulation, the kind of tremolo you would expect from a vintage amp. FM stands for filtered modulation, which Caroline describes as subtle, beautiful, and less invasive on your playing. Guitar Pedal X's reviewer found the Filtered mode subtler, with a different timbre than the Amplitude voicing, so the two modes cover a wide range from obvious pulsing to a gentler shift in character.
Can the Parabola be used as an overdrive or boost?
Yes. Caroline added pre and post effect gain stages for both overdrive and volume boost, so the pedal can push an amp or lift your signal as well as modulate it. Guitar Pedal X described the Pawnshop Edition as a higher gain, preamp assisted, amp style tremolo, which reflects how much gain staging is built into the circuit.
What power supply does the Caroline Parabola need?
The Parabola runs on 9V DC, center negative, the standard pedal supply. Use a regulated supply or a quality daisy chain rated for your whole board, and avoid unregulated supplies, which can put noise and incorrect voltage into an analog circuit like this one.
Is the Parabola Pawnshop Edition still available?
No, not from the maker. Guitar Pedal X reported in May 2026 that the Pawnshop Edition had long since sold out on the Caroline Guitar site, with a handful of units remaining on Reverb.com at $219. The standard Parabola remains the version to look for from the maker.
Sources (4)
- Parabola, Caroline Guitar Company, 2026-09-07
- Parabola Solid State Tremolo by Caroline Guitar Company, RockBoard PedalPedia, 2026
- Guitar Pedal X, Guitar Pedal X, 2026-05-25
- Caroline Parabola Solid State Tremolo, Delicious Audio, 2018-04-09
