The Jam Pedals Retrovibe Mk4 is a significant update to the company’s respected Uni-Vibe-inspired pedal, refining its classic, photo-cell-based modulation for modern playability. It delivers the quintessential, warm, three-dimensional swirl associated with vintage “vibe” units in both lush chorus and throbbing vibrato modes, with notable improvements in tonal depth and range over earlier versions.
The Mk4’s defining upgrades are its performance-focused controls. The addition of a Tap Tempo footswitch (with an external input) brings essential rhythmic precision, allowing you to sync the modulation speed to a song. The new Ramping function is a creative standout, letting you smoothly sweep between your current speed and a preset target speed for dramatic, swooshing transitions at the touch of a button. An expression pedal input also provides real-time, hands-free speed control.
Compared to its predecessor, the Mk3, the Mk4 offers a wider sweep in both its Speed and Depth controls, providing access to more extreme, psychedelic sounds and more subtle, atmospheric textures. Housed in JAM’s distinctive, high-quality etched enclosure, the pedal maintains a simple, intuitive core interface while adding substantial new flexibility.
For players seeking the authentic, organic throb and swirl of a classic Uni-Vibe but who require stage-ready features like tap tempo and dynamic control, the Retrovibe Mk4 successfully bridges the gap between vintage character and modern functionality. It’s a versatile and musical choice for everything from subtle Hendrix-style thickening to full-on, tempo-synced modulation.
Jam RetroVibe Mk3
The Jam Retrovibe Mk3 is a two-knob Uni-Vibe recreation featuring original NOS 2SC828 transistors and carbon comp resistors.
Like the vintage unit, it offers both Vibrato and Chorus modes and lets you dial in anything from slow-rate wavy sounds all the way to fast Leslie-speaker effect, which can be controlled via an EXP4 expression pedal.
An internal trim pot affects the maximum intensity of the effect, but also dramatically manipulates the sound of the effect while maintaining its true vintage character.
Mk3 features a soft click footswitch and, unlike previous versions, accepts the most common 10K passive Expression pedals.
We added this list to our article about the Best Uni-Vibe Pedals, here are the videos of it!
These are videos of Mk2
Comprised of photocells, a bulb, original NOS 2SC828 transistors and carbon comp resistors, the RetroVibe mk.2 delivers the majestic sounds of the best Uni-Vibe pedals from back in the day, but housed in a modern pedalboard-friendly enclosure and featuring standard 9V DC operation, internally lifted to 15V DC.
Choose between the Vibrato and Chorus settings and navigate from slow-rate wavy sounds all the way to fast Leslie-speaker effects!
Use it in conjunction with our EXP4 Expression pedal for real-time Speed control!
An added twist! We have incorporated an internal trimmer that affects the maximum intensity of the effect, but also dramatically manipulates the sound of the RetroVibe mk.2, all the while, maintaining the pedal’s true vintage character.
Roses are red violets are blue the RetroVibe’s purple and you’ll looove it too!
