Smalls Green Rhino Overdrive MkV (WM22)

The Green Rhino MkV is the smallest version of an overdrive that comes in several sizes. The pedal is analogue and mono, measures roughly 61 by 104 millimetres, and so suits anyone who has little room left on a crowded pedalboard. It is built in Taiwan and also works with bass guitar.

The sound is rough and grainy, with plenty of grit once you turn the drive up. Volume, Drive and Tone handle the basics. Two more knobs are there for finer shaping. Freq lifts or cuts the signal at 100 or 500 hertz, and which of the two it is gets decided internally, so you have to open the enclosure to swap. Curve takes the edge off the high end when the pedal starts to sound too aggressive. There is also a switch with Classic and Modern positions, which gives you two starting points without modifying anything.

With those controls you can push an amp from clear to solid to raw. The pedal is mostly interesting if you want an overdrive you can steer to your own taste that still takes up little space. The bypass is true bypass.

You power it with a 9 volt adapter with the centre pin negative, or with a battery. It draws about 18.5 milliamps. Input and output are both mono.

Where it falls short is in operation: the choice between 100 and 500 hertz cannot be changed while playing. If you want a pedal that barely adds a colour of its own, this is not the right one: this is an overdrive that makes itself heard.