We’ve harped on the fact before that there are so many great-sounding overdrive/distortion pedals on the market today. And regardless of whether they employ silicon or germanium transistors, guitarists generally feel distortion from a pedal should be produced exactly like distortion from a great amp, meaning it has to start with a vacuum tube.
Tube-driven pedals have been around for decades, but most present a significant challenge because they require a good deal of energy to produce sound, and that usually means “power cord.” Outside of the logistics of having to find (or bring) a multiple outlet, attaching a 110-volt cord can introduce a lot of noise to one’s signal path.
With its Cooltron series, Vox set about to resolve these issues while providing a pedal with true tube tone. The plan was to make a pedal that could run on inexpensive AA batteries. Using a 12AU7, each Cooltron has not one, but two circuits; the first is servo-biased and connects the plate of the tube with the grid. The second gets the current supply to the heater elements in the tube (though it isn’t much). In conjunction (and in theory), they cause even clipping and smooth harmonics and distortion, just like an overdriven tube.
Does it work? In a monosyllable, yup. Each of the three pedals has full, smooth distortion with deep, tight bass, and very pleasant treble. Currently, the line is made up of the Big Ben Overdrive, Brit Boost, and Bulldog Distortion.
The Big Ben offers the simplest layout, with knobs for Volume, Tone, and Gain. It offers the low/mid-level of distortion prized by roots rockers and blues guys. The Brit Boost has the same controls, along with a Treble Boost footswitch.
The Bulldog Distortion offers the widest range of distortion and, predictably, the most knobs. It has two distortion circuits; the first being the basic vintage-type, while the second can go to shred and beyond. The cool thing about the second circuit is that, while similar circuits can sound edgy, harsh, and excessively trebly, this one sounds smooth even while producing decibles seemingly comparable to a 747 on takeoff.
Vox claims the batteries can last up to 16 hours. Being skeptical and curious (and having little else on the docket one day), we took the Bulldog – the Cooltron with the most knobs and therefore (presumably) the most power-sucking circuitry – turned everything up to 11, jammed a George L’s cable end into the input to activate the pedal, and hit the stopwatch. The red LEDs that indicate the effect faded at 18 hours, 23 minutes and went totally dead at 19 hours, six minutes and 23 seconds. Also, all Cooltrons work with most common 9-volt wallwart adapters.
The Cooltrons’ sturdy, chrome-plated metal cases are some of the nicest we’ve ever seen, with additional visuals provided by a small purple LED underneath the semi-exposed tube. At 61?2″ x 6″, they’ll actually fit on a pedalboard, and the price compares favorably to other high-end chip-based pedals. – Bob Dragich
Vox Cooltron Big Ben Overdrive, Brit Boost, and Bulldog Distortion
Features: 12AU7 tube running at low wattage. Can be powered by 4 AA batteries (included) or a 9-volt adapter (not included).
Price: $225 (Bulldog and Brit Boost) and $200 (Big Ben).
Contact: Vox Amplification Ltd., 9 Newmarket Court, Kingston, Milton Keynes, MK10 OAU, UK; voxamps.co.uk.
This article originally appeared in VG‘s Nov. ’05 issue. All copyrights are by the author and Vintage Guitar magazine. Unauthorized replication or use is strictly prohibited.