BBE Soul Vibe Tech Focus: In the Light Box

All rotary/vibe pedals owe thanks to Japan’s Shin-ei, creator of the 1960s Uni-Vibe. It was such a cool and innovative pedal for its time, but finding one in good working order forty years later is nearly impossible. We bought several of them and even the one we spent $1500 on barely worked. Now that it does, well, it’s not for sale. With credit where it’s due, let’s take a look at how these effects work and why the Soul Vibe is a great choice for the serious guitarist jonesing for authentic rotary tone.

The element of an old Uni-Vibe which controls the pulsating effect consists of class A sine-wave oscillator feeding an incandescent bulb which shines on four photo cells positioned around the bulb. The bulb and cells are contained in a metal can which keep any light from outside from leaking in and reaching the photo cells. As the voltage of the bulb is varied, the amount of light picked up by the photo changes, changing the output voltage of the cells. By the way, the concept of a lamp shining on a photo cell is the same principle used in an optical compressor or old Fender tremolo circuit.

While the setup inside an old Uni-Vibe works, there was considerable variance in sound from one Uni-Vibe to the next, and that was when they were new! Given decades of use, the bulb has often died and been replaced. Even when working, an incandescent bulb will lose its luminosity (brightness) over its life span, so the light that reaches the photo cells becomes less and less. What’s more, the photo cells stand up from the circuit board and are difficult to get aligned properly in relation to the bulb. If the pedal is bumped around, the position of the photo cells can shift causing the sound to change.

The Soul Vibe is the same in principle, but much improved in execution. Soul Vibe has a small box with the photo cells firmly attached to the inside of walls of the box, and an LED lamp rigidly mounted in the center of the box. This means the positions of the LED and the photocells can’t change, which makes for consistent performance and rugged dependability. What’s more, the LED lamp does not measurably lose its luminosity over its extremely long life span.

Video Demo

 

Nick Jaffe demo and discussion of Soul Vibe

 

We've changed the graphics from what you see in the demos below, but it's the same great tone!

Floyd and melodic picking style

Trower style

VP Engineering Paul Gagon - Tech Session

Guitar World Magazine Review - Soul Vibe and Mind Bender

Features include

• Speed and Intensity controls
• Blue status LED pulses at rate of speed selected
• LED photocell box for precision and durability
• 82K Ohms input impedance for vintage-correct rotary pickup loading
• 1K Ohms output impedance when engaged
• 1% metal-film resistors for consistency
• High-voltage poly caps for better tone
• Military-spec circuit board for reliability
• Easy access battery compartment
• True hardwire bypass
• 5-year warranty

Designed and Engineered in USA
Made in China

Reviews

“The Soul Vibe is a worthy entrant to the market. It’s easy to use, sounds very close to the original, and unlike a vintage Univibe, is made of high-strength steel and other high-quality components."

Eric C. Shoaf, Vintage Guitar

Taking Soul to New Levels - The BBE Soul Vibe

Vintage Guitar