The Radial StageBug SB-4 is a compact active direct box that has been optimized for use with piezo transducers. This enables violin, dobro, mandolin, cello, upright bass and other instruments that are best amplified using a piezo to be connected without compromising the tone or frequency response.The design begins with a -+" input for the instrument pickup. Unlike typical direct boxes that have a 1meg-ohm input impedance, the SB-4 features a very high 5meg-ohm impedance that smoothes out troublesome peaks that give piezos a bad name. The higher impedance also broadens the frequency response for a more natural and pleasing sound. The active circuit performs the high-to-low impedance conversion and balances the signal to enable long runs upwards to 100 meters without loss, delivering spectacular linearity and low distortion throughout the audio range.To help eliminate feedback on stage, the SB-4 is equipped with a high-pass filter and 180- polarity reverse switch. The high pass filter el