Orange OB1-500 bas top.
The OB1 splits the input instrument signal into two separate paths. One side amplifies the clean signal, with all the clarity you would expect from Orange. The other adds stages of gain to the upper harmonics only, controllable via the amp’s Gain knob. These two elements are combined using the amplifier’s Blend control which adjusts the mix between clean and dirty. The Blend control can then be remotely engaged or defeated using the optional footswitch.
The Gain and Blend’s range allows for almost anything, from a subtle level boost to cut through the mix, added girth and presence at moderate settings to fatten up chorus passages, to fully saturated savagery at the extremes. However you dial it, the OB1 always maintains the critical low end definition, right the way up to the most offensive settings!