By designing the JDX-48 to be comfortable deriving its signal from a powered signal from the head, it is far superior to DIs built into guitar heads, which typically tap the preamp output. That approach entirely misses the characteristics that power tubes and solid state power stages lend to a guitar sound.

Apart from taking the complete guitar amp signal as its sound source, the Radial JDX-48 features 100% discrete class-A circuitry and a transformer-coupled 'reactive load' that captures both the sound from the amp head along with the back electromagnetic impulse from the loudspeaker. This produces a more realistic rendering than the usual resistive pad offered by other manufacturers. The signal is then processed via a carefully designed multi-stage filter to emulate the tone of a 4x12 half stack cabinet.