VOX CT-02OD Big Ben Overdrive Pedal

Introducing the COOLTRON series of effect pedals, seven very special stompboxes that use a 12AU7 preamp-type tube at low voltage to deliver the kind of tone that, until now, would have been impossible to achieve in a battery-powered pedal.

Want to know how it all works?

Normally, tubes are used at high voltages and this restricts their use in battery-powered devices such as guitar effects pedals. Historically, attempts have been made to use tubes at low voltages in what has been dubbed “starvation” mode, but these circuits don’t allow the tube to function in an acceptable manner. The tube simply cannot be biased to a satisfactory operating condition. Plus, the necessary heater filament current is too high to deliver acceptable battery life. Imagine how annoying it would be to have to change batteries every ten minutes during a gig

Here’s what makes the COOLTRON system tick. The COOLTRON circuit basically operates by using two very special signal paths. The first is the “servo circuit,” which provides the right conditions between the plate of the tube and the grid. This achieves controllable, stable parameters for the tube and provides the correct operating conditions for the tube to function as it would if run at a higher voltage. The second circuit is a patented power supply that provides a low voltage, low current supply to the heater elements in the tube. Since the tube is now running at such a reduced supply level, the anode current is much smaller than normal. This means that the amount of heat required at the cathode to achieve sufficient cathode current emission is much smaller – hence the ability to run the heaters at a lower level and for COOLTRON pedals to run for 16 hours on 4 x AA batteries

The COOLTRON system provides true tube sonic performance at very low voltage and at reduced heater current – ideal for inclusion into guitar effects pedals. COOLTRON guitar effects pedals offer valuable tube type sonic performance.

Big Ben Overdrive

Preserve your amp’s warm, silky tone while pushing your sound into overdrive The tube-powered Big Ben Overdrive pedal responds to your playing dynamics and cranks out that extra firepower when you really dig in and want to cut through. The Gain knob varies the overall gain of the pedal from bluesy and mellow to fat and saturated, while the Tone knobs adjusts that overall tonality of the pedal. As with all COOLTRON pedals, the Big Ben’s true bypass allows you to let your signal flow through untouched.