The Colombo Audio Eruption is a distortion pedal from Italian maker Colombo Audio Electronics, designed to get the guitar sound of the first six Van Halen albums, the sound Eddie Van Halen used to call the brown sound. Delicious Audio's Paolo De Gregorio describes it as a Plexi overdrive/distortion, and it sits among the site's coverage of distortion pedals and overdrive pedals.1
The pedal came out of a wave of tribute gear: the death of Eddie Van Halen in October 2020 spurred a series of releases dedicated to him, and the Eruption is Colombo's way of paying tribute to the legend.1
What it does
The circuit is based on the Marshall 1959 Super Lead Plexi-style amp tone of those early records. The amp used on them was a Marshall 1959 Super Lead head that had been modded with a Variac transformer, a device that varies the voltage feeding the amp so it runs under-powered and changes how it breaks up.1
The Eruption recreates that mod in a single knob:
| Variac setting | What you get |
|---|---|
| At minimum | Keeps the character of a stock Plexi, the typical historic Marshall sound with even more gain available |
| Raised | Reduces the same frequencies an under-powered amp loses, emulating the Variac physical phenomenon and the brown sound |
"Eruption is therefore a dual function pedal: those who are fond of the original Plexi sound can keep the Variac control down and get the typical Marshall historic sound (with even more gain available)."
Delicious Audio covered the pedal in May 2021 and added it to its article on Plexi-style pedals.1
Videos
Brett Kingman
Luca Colombo
Luca Colombo
Questions
What is the Variac control on the Colombo Audio Eruption?
The Variac control manages a virtual voltage inside the pedal. At its minimum the Eruption keeps the character of a stock Marshall Plexi. As you raise it, the pedal reduces the same frequencies an under-powered amp loses, emulating the physical effect of the Variac transformer that was fitted to the amp used on the first six Van Halen records.
Is the Eruption an overdrive or a distortion?
It is described as a dual-function pedal covering both. With the Variac control down it delivers the typical historic Marshall sound with even more gain available than the original amp. With the Variac raised it recreates the brown sound Eddie Van Halen called his own on those early albums.
Sources (1)
- Colombo Audio Eruption Plexi Overdrive/Distortion, Delicious Audio, 2021-05-06
Eddie Van Halen