The Rotosound Wobbler (model RWB1) is a tremolo guitar effects pedal: it raises and lowers the volume of your signal in a repeating cycle, the way the tremolo circuit of an older amplifier does. Rotosound built it around a vintage optical attenuator, the lamp-and-photocell approach used in classic amp tremolo circuits, and the company says it produces "a variety of sounds that captures a vintage valve amp tremolo tone"12. The pedal is discontinued, so it is available only secondhand.
What sets the Wobbler apart from most tremolo pedals is a control that sweeps between two signal paths, one silicon and one germanium. Guitar Pedal X described it as "A Tremolo that allows users to sweep between silicon (Silly) and germanium (Germ) signal paths, which offers a unique vi"3. That blend control is the pedal's main point of difference from a straightforward optical tremolo.
The Wobbler is discontinued. Rotosound's product page marks it as no longer in production, so finding one means the secondhand market. The earlier announcement version of the pedal is covered on the Rotosound Green Wobbler page.
Controls and how it works
The Wobbler keeps its control set simple. Rotosound specifies a smooth, wide range control of rate and depth2: rate sets how fast the volume pulses, depth sets how far the signal dips toward silence at the bottom of each cycle. On top of those two sits the silicon-to-germanium sweep, which shapes the character of the tremolo rather than its speed or intensity.
| Control | What it does |
|---|---|
| Rate | Sets how fast the volume pulses, described by Rotosound as a smooth, wide range control2 |
| Depth | Sets how far the signal dips at the bottom of each cycle, also a smooth, wide range control2 |
| Silicon-to-germanium sweep | Blends between the silicon and germanium signal paths, shaping the tremolo's character rather than its speed or depth3 |
The optical attenuator at the heart of the pedal works the way vintage amp tremolo did, by varying how much light reaches a light-dependent element in the signal path. Guitar Interactive reported that this "provides a variety of sounds that captures a vintage valve amp tremolo tone"1.
Power and switching
The Wobbler runs from an external power supply through an input socket rated 9 volt to 18 volt, internally regulated2. That range means it accepts a standard 9V pedal supply as well as higher-voltage units, and Rotosound lists no battery option. Switching is true bypass, so the pedal is out of the signal path entirely when it is off2.
| Specification | Value |
|---|---|
| Power input | External supply via input socket2 |
| Voltage range | 9 volt to 18 volt, internally regulated2 |
| Battery | Not listed2 |
| Bypass | True bypass switching2 |
| Construction | Hand wired, made in England2 |
Where it came from
The Wobbler was designed for Rotosound by John Oram, whose background includes VOX and Trident2. It is one of a range of retro effects pedals, each finished in a durable pressed steel box with colored hammer powder coatings, which is where the Wobbler's green finish came from1.
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Guitar Pedal X listed the Wobbler Tremolo at £195 when Rotosound reissued its vintage pedal range3.
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Questions
Is the Rotosound Wobbler true bypass?
Yes. Rotosound lists true bypass switching for the Wobbler, so with the pedal off the signal passes through without the circuit coloring it. Like any true bypass pedal, long chains of them can benefit from a buffer elsewhere on the board.
Can the Rotosound Wobbler run on 18 volts?
Yes. The Wobbler has an input socket for a power supply connection that is internally regulated from 9 volt to 18 volt, so it accepts supplies anywhere in that range. Rotosound does not list a battery option or a current draw figure.
Is the Rotosound Wobbler still made?
No. Rotosound's product page marks the Wobbler as discontinued, so it is no longer in production. It appeared as part of a range of six hand-wired pedals Rotosound launched in 2014, and secondhand units are the way to find one now.
Where is the Rotosound Wobbler made?
In England. Rotosound describes its stompboxes, the Wobbler included, as hand wired and made in England. The pedal was designed by John Oram, whose background includes VOX and Trident.
Sources (4)
- Six New Effects Pedals Released by Rotosound, Guitar Interactive Magazine, 2014-03-03
- Wobbler | Tremolo Guitar Effects Pedal • Rotosound Music Strings, Rotosound, 2025-02-20
- Guitar Pedal X, Guitar Pedal X, 2025-02-21
- Rotosound Introduce Six New Effects Pedals, Guitar Interactive Magazine
