Posts Tagged ‘response’

In any tube amplifier, the cathode resistor can be bypassed with a capacitor to increase the gain.  Aside from the benefit of wringing extra gain from each stage, a shelving filter is created by this RC combination.  Since the resistor sets the bias of the stage and would normally need to remain at a particular value, the capacitor can be be chosen, or changed, to set the cut off of the filter.

In most modern guitar amps, the cut off is set to voice the stage for a particular bass response.  While there are many filtering options in an amp, the cathode cap is  powerful.  The frequencies below cut off are amplified much less, which means that frequency also gets driven less during overdrive or clipping.  For low frequencies, this is important. (more…)